QA_QC Concrete

QCS

QCS 2014 Section 05: Concrete Page 1 Part 01: General

1 GENERAL------------------------------------------------------------------------------------------------------------ 2

1.1 INTRODUCTION --------------------------------------------------------------------------------------------------- 2 1.1.1 Scope ----------------------------------------------------------------------------------------------------------------- 2

1.1.2 References----------------------------------------------------------------------------------------------------------- 2

1.1.3 Definitions ------------------------------------------------------------------------------------------------------------ 3

1.1.4 Approved Products ------------------------------------------------------------------------------------------------ 4

1.2 IMPLEMENTATION ----------------------------------------------------------------------------------------------- 4 1.2.1 Approved Installers ------------------------------------------------------------------------------------------------ 4

1.2.2 Field Quality Control ----------------------------------------------------------------------------------------------- 4

1.2.3 Rejected materials ------------------------------------------------------------------------------------------------- 5

1.2.4 Records --------------------------------------------------------------------------------------------------------------- 5

QCS


1 GENERAL

1.1 INTRODUCTION

1.1.1 Scope

1 This Section includes the requirements for concrete work for pipelines, roadworks, runways,

structures, water retaining structures, foundations and bases for structures and equipment.

2 This Part includes relevant standards, definitions, abbreviations, and requirements for testing

facilities, rejected materials, and record keeping.

3 Related Sections are as follows:

This Section:

Part 2, Aggregates

Part 3, Cementitious Materials

Part 4, Water

Part 5, Admixtures

Part 6, Property Requirements

Part 7, Concrete Plants

Part 8, Transportation and Placing of Concrete

Part 9, Formwork

Part 10, Curing

Part 11, Reinforcement

Part 12, Construction Joints

Part 13, Inspection and Testing of Hardened Concrete

Part 14, Protective Coatings to Concrete

Part 15, Hot Weather Concrete

Part 16, Miscellaneous

Part 17, Precast Concrete

Part 18, Prestressed Concrete

Part 19, Water Retaining Structures

Section 1, General

Section 2, Quality Assurance and Quality Control

Section 4, Foundations and Retaining Structures

Section 6, Roadworks

Section 8, Drainage Works

Section 9, Mechanical and Electrical Equipment

1.1.2 References

1 The following standards are referred to in this Part:

ASTM C31 .................. Standard Practice for Making and Curing Concrete Test Specimens in

the Field

ASTM C39 .................. Standard Test Method for Compressive Strength of Cylindrical

Concrete Specimens

ASTM C143 ................ Standard Test Method for Slump of Hydraulic-Cement C Concrete

ASTM C1064 .............. Standard Test Method for Temperature of Freshly Mixed Hydraulic-

Cement Concrete

http://www.astm.org/Standards/C31C31M.htm

http://www.astm.org/Standards/C31C31M.htm

QCS


BS 6100, .................... Glossary of Building and civil engineering terms

BS EN 932-1 .............. Tests for general properties of aggregates. Methods for sampling

BS EN 932-2 .............. Tests for general properties of aggregates. Methods for reducing

laboratory samples

BS EN 12350-1 .......... Method of sampling fresh concrete in site

BS EN 12350-2 .......... Testing fresh concrete. Slump-test

BS EN 12390-1 .......... Shape, dimensions and other requirements for specimens and moulds

BS EN 12390-2 .......... Making and curing specimens for strength tests

GSO ISO 1920-1 ........ Testing of concrete —Part 1: Sampling of fresh concrete

GSO ISO 1920-2 ........ Testing of concrete – Part 2: Properties of fresh concrete

GSO ISO 1920-3 ........ Testing of concrete – Part 3: Making and curing test specimens

1.1.3 Definitions

1 Definitions used in this Section.

The following are terms and abbreviations used:

C degree Celsius

cal calorie

cm centimetre

d day

fck,cyl Characteristic compressive strength of concrete determined by testing cylinders

fc,cyl Compressive strength of concrete determined by testing cylinders

fck,cube Characteristic compressive strength of concrete determined by testing cubes

fc,cube Compressive strength of concrete determined by testing cubes

fcm Mean compressive strength of concrete

fcm,j Mean compressive strength of concrete at the age of (j) days

GGBS ground granulated blast furnace slag

GUTS guaranteed ultimate tensile strength

h hour

kg kilogram

kJ kilojoule

kN kilonewton

l litre

m metre

m2

square metre

m3

cubic metre

mg milligram

min minute

mm millimetre

mm2

square millimetre

months months

MPa mega Pascal

kPa kilo Pascal

MSRPC moderate sulphate resisting Portland cement

OPC ordinary Portland cement

PFA pulverised fuel ash

PVC polyvinylchloride

s second

SF silica fume

SRPC sulphate resisting Portland cement

QCS


ton 1000 kg

ppm part per million

micron 10-6

µm 10-6

meter

2 Reference to a technical society, institution, association or governmental authority is made in

accordance with the following abbreviations.

AASHTO American Association of State Highway and Transportation Officials

ACI American Concrete Institute

ASTM American Society for Testing and Materials

AWS American Welding Society

BS British Standard

BSCP British Standard Code of Practice

BSI British Standards Institution

C & CA Cement and Concrete Association

CIRIA Construction Industry Research and Information Association

CRSI Concrete Reinforcing Steel Institute

CS Concrete Society

DIN Deutsches Institut fur Normung e.V.

EN Euro Norm

FHWA Federal Highway Authority

GSO GCC Standardization Organization

ICE Institution of Civil Engineers

ISO International Organization for Standardization

PCI Prestressed Concrete Institute

QCS Qatar Construction Specifications

QS Qatar Standards

UK DfT United Kingdom Department for Transport

Products

1.1.4 Approved Products

1 The contract specific documentation may identify approved products and approved or

prequalified manufacturers and suppliers of products used in concrete work.

1.2 IMPLEMENTATION

1.2.1 Approved Installers

1 The contract specific documentation may identify approved or prequalified providers of

concrete construction services.

1.2.2 Field Quality Control

1 The Contractor shall carry out the test procedures required by this Section and any other

tests and test procedures as directed by the Engineer from time to time. The test procedures

shall be carried out using the facilities of an approved independent testing laboratory.

2 Supply, storage, sampling and testing of all materials shall be the responsibility of the

Contractor, unless the Contract specifies otherwise.

QCS


3 The Engineer may also require the Contractor to take samples of materials and deliver them

to the Central Materials Laboratory for additional tests to be carried out by the Employer.

Sampling procedures shall be in accordance with BS EN 932 or relevant ASTM Standards,

and sample sizes shall conform to the requirements shown in Table 1.1.

4 The minimum equipment required for testing on Site is given in Table 1.2. This equipment

shall be maintained on Site at all times during concreting operations together with the

necessary scoops, buckets, sample containers, and other items required for sampling. The

cube curing tank shall be located in an air-conditioned area as stated in part 06.

1.2.3 Rejected materials

1 Any material rejected by the Engineer, in particular cement which has deteriorated or

aggregates which have segregated or become contaminated, shall be immediately removed

from the Site.

1.2.4 Records

1 The Contractor shall maintain on the Site full records of all work carried out accurately

related to the location of the work on site, which shall include:

(a) the time and date when all concrete was poured, formwork removed and when formwork props were fully removed

(b) all cubes and other tests

(c) daily maximum and minimum temperatures.

2 One copy of all test results shall be sent to the Engineer immediately upon completion of the

tests

Table 1.1

Sampling Procedure and

Minimum Sample Sizes for Central Materials Laboratory

Material Test Min. Sample

Cement Full range of tests Composite sample of 7 kg

taken from at least 12 bags

Aggregate

Full range of tests 200 kg

Sieve analysis

Chemical analysis

Soundness test

Water absorption

Particle density

Flakiness index

Fines content

LA Abrasion value

50 kg

Reinforcement Tensile test 500 mm

Bend test 300 mm

Water Full range of tests 5 litres

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Table 1.2

Minimum Testing Equipment for Each Site*

Test Equipment to be Provided Minimum Number

Required

Slump test BS EN

12350-2

or

GSO ISO 1920-2

or

ASTM C143

Slump cone with base plate

Compacting rod, circular cross-section

and round ends

Remixing container, 300 mm ruler,

moist cloth

Scoop and shovel

Timer

1

1

1

1

1

Cube making

BS EN 12390-1

and

BS EN 12350-1:2000

or

GSO ISO 1920-1

and

GSO ISO 1920-3

or ASTM C31 and C39

100 or 150 mm cubical or cylindrical

moulds1

Compacting rod or bar Set of tools for

assembling and stripping moulds

Remixing container

Trowel, Scoop, Shovel and Mallet

Mould release agent in closed

container with brush

6

1

1

-

-

1

Cube curing BS EN

12390-2

or

GSO ISO 1920-3

or ASTM C39

Hessian or sacking, impervious sheet

Maximum/minimum thermometer

Waterproof marking crayon/paint or

equivalent

Curing tank (in air conditioned room)

Supply of packing materials for sending

cubes to commercial laboratory

lot

1

1

1

Lot

ASTM C1064

Concrete thermometer 1

1 - The use of 100 mm cube and cylinder moulds are permitted when the nominal maximum aggregate size is not greater than 20mm

END OF PART

QCS

QCS 2014 Section 05: Concrete Page 1 Part 02: Aggregates

2 AGGREGATES ....................................................................................................... 2

2.1 GENERAL ............................................................................................................... 2

2.1.1 Scope 2

2.1.2 References 2

2.1.3 Definitions 3

2.1.4 Source Approval 4

2.1.5 Sampling 4

2.2 QUALITY AND TESTING ........................................................................................ 5

2.3 STORAGE AT CONTRACTOR PLANT ................................................................... 5

2.4 FINE AGGREGATE FOR CONCRETE AND MORTAR ........................................... 7

2.5 COARSE AGGREGATE FOR CONCRETE ............................................................. 8

2.6 COMBINED AGGREGATE FOR CONCRETE......................................................... 8

2.7 WASHING AND PROCESSING .............................................................................. 9

2.8 LIGHTWEIGHT AGGREGATES .............................................................................. 9

2.9 COARSE RECYCLED AGGREGATES ................................................................... 9

QCS


2 AGGREGATES

2.1 GENERAL

2.1.1 Scope

1 This part covers the requirements of aggregates for use in structural concrete.

2 Related Sections and Parts are as follows:

This Section .....

Part 3, .............. Cementitious Materials

Part 4, .............. Water

Part 6, .............. Property Requirements

Part 7, .............. Concrete Plants

Part 8, .............. Transportation and Planning of Concrete

Part 15, ............ Hot weather Concreting

Part 17, ............ Structural Precast Concrete

Part 18, ............ Prestressed Concrete

2.1.2 References

ASTM C33 ..................Standard Specification for Concrete Aggregates

ASTM C40 ..................Test Method for Organic Impurities in Fine Aggregates for Concrete

ASTM C88 ..................Test Method for Soundness of Aggregates by Use of Sodium Sulphate

or Magnesium Sulphate

ASTM C123 ................Test Method for Lightweight Pieces in Aggregate

ASTM C127 ................Test Method for Specific Gravity and Absorption of Coarse Aggregate

ASTM C128 ................Test Method for Specific Gravity and Absorption of Fine Aggregate

ASTM C131 ................Test Method for Resistance to Degradation of Small-Size Coarse

Aggregate by Abrasion and Impact in the Los Angeles Machine

ASTM C136 ................Standard Test Method for Sieve Analysis of Fine and Coarse

Aggregate

ASTM C142 ................Test Method for Clay Lumps and Friable Particles in Aggregates.

ASTM C535 ................Test Method for Resistance to Degradation of Large-Size Coarse

Aggregate by Abrasion and Impact in the Los Angeles Machine

ASTM C702 ................Standard Practice for Reducing Samples of Aggregate to Testing Size

ASTM D75 ..................Standard Practice for Sampling Aggregates

BRE Digest 330-2 .......Alkali-Silica Reaction in Concrete – Detailed Guidance for New

Construction.

BS 933-3 ....................Tests for geometrical properties of aggregates Determination of

particle shape. Flakiness index

BS 933-7 ....................Tests for geometrical properties of aggregates Determination of shell

content. Percentage of shells in coarse aggregates

BS 933-9 ....................Tests for geometrical properties of aggregates Assessment of fines.

Methylene blue test

QCS


BS 933-11 ..................Tests for geometrical properties of aggregates Classification test for

the constituents of coarse recycled aggregate

BS 1097-6 ..................Tests for mechanical and physical properties of aggregates

Determination of particle density and water absorption

BS 8500 part 2 ...........Concrete. Complementary British Standard to BS EN 206-1.

Specification for constituent materials and concrete

BS EN 12620 ..............Aggregates for concrete

BS EN 1744-1 ............Tests for chemical properties of aggregates, Chemical analysis

BS EN 1744-5 ............Tests for chemical properties of aggregates. Determination of acid

soluble chloride salts

BS EN 1367-2 ............Tests for thermal and weathering properties of aggregates.

Magnesium sulphate test. BS EN 1367-4 Determination of drying

shrinkage

BS EN 933 ..................Tests for geometrical properties of aggregates

BS EN 1097-2 ............Tests for mechanical and physical properties of aggregates. Methods

for the determination of resistance to fragmentation

BS EN 1097-6 ............Tests for mechanical and physical properties of aggregates.

Determination of particle density and water absorption

BS EN13055-1 ...........Lightweight aggregates. Lightweight aggregates for concrete, mortar

and grout.

BS PD 6682-1 ............Aggregates for concrete. Guidance on the use of BS EN 12620

BS PD 6682-4 ............Aggregates Lightweight aggregates for concrete, mortar and grout.

Guidance on the use of BS EN 13055-1

EN 13139 ..................Aggregates for mortar

EN 998-1 ...................Specification for mortar for masonry Rendering and plastering mortar

EN 998-2 ...................Specification for mortar for Masonry mortar

ISO 9001:2008 ...........Quality management systems -- Requirements

ISO 17025 ..................General requirements for the competence of testing and calibration

laboratories

RILEM AAR1 ..............RILEM Recommended Test Method AAR-1 “Detection of potential

alkali-reactivity aggregates”, Petrographic method

RILEM AAR3 ..............RILEM Recommended Test Method AAR-3 “Detection of potential

alkali-reactivity - 38°C test method for aggregate combinations using

concrete prisms

2.1.3 Definitions

1 Aggregate: granular material used in construction and may be natural, manufactured or

recycled.

2 Natural aggregate: aggregate from mineral sources which has been subjected to nothing

more than mechanical processing.

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3 Manufactured aggregate: aggregate of mineral origin resulting from an industrial process

involving thermal or other modification.

4 Recycled aggregate: aggregate resulting from the processing of inorganic material previously

used in construction.

5 Lightweight aggregate: aggregate of mineral origin having a particle density not exceeding

2,000 kg/m3 or a loose bulk density not exceeding 1,200 kg/m3.

2.1.4 Source Approval

1 The Contractor shall use only those imported materials sourced from an Accredited Quarry

Producer or Accredited Supplier and which have been approved by Qatar Standards or their

representatives.

2 The accredited aggregate suppliers shall provide the source name(s) for every shipment of

aggregates delivered to the concrete supplier.

3 The source of material supply may be changed by the Contractor during the project, provided

that the replacement materials shall be sourced from an Accredited Quarry Producer and the

replacement materials are not significantly different in terms of physical and chemical

properties, thus ensuring that the resultant concrete continues to comply fully with the

specified requirements.

4 When considering whether an aggregates supplier and aggregates producer are suitable to

be Accredited, preference will be given to organisations with a proper quality management

system, such as ISO 9001 or another quality management system approved by Qatar

Standards.

5 When requested by the engineer, the aggregate supplier shall provide a geotechnical

analysis on the rock samples before blasting and grinding to ensure the proper quality of

materials.

6 The aggregates shall be properly stocked and labelled without intermingling at any storage

area.

7 When requested by the engineer, the aggregates supplier shall provide data for the past 6

months that shows the consistency of materials and conformity with this specification.

8 The supplier shall verify the compliance of aggregates as per QCS by an independent

qualified testing agency accredited to ISO 17025, and approved by Qatar Standards.

2.1.5 Sampling

1 The Contractor shall provide samples of both fine and course aggregate to the Engineer, in

accordance with the requirements of relevant standards in QCS for sampling, sample

reducing and testing of Aggregates, for testing at least two weeks before beginning deliveries

to the Site.

2 All samples shall be taken in the presence of the Engineer or an approved testing agency

assigned by the Engineer.

3 Aggregate sampling and testing shall be conducted by qualified staff.

QCS


2.2 QUALITY AND TESTING

1 Aggregates shall consist of tough, hard, durable and uncoated particles containing no

harmful material in quantities sufficient to adversely affect the concrete or reinforcing steel,

and shall contain no materials likely to cause staining or otherwise disfigure the concrete

surface.

2 Aggregates shall be obtained from a source approved by the Engineer.

3 Aggregate shall meet the requirements given in Table 2.1. Additional tests detailed in BS EN

12620 with BS PD 6682, EN 13139, EN 998-1, EN 998-2, or relevant ACI and ASTM

standards and codes of practice may be required by the Engineer to satisfy certain

requirements.

4 Contractor shall provide all data as specified in QCS.

5 Sampling of the aggregates shall be carried out in accordance with the requirements of BS

EN 12620, BS EN 933, or ASTM D75 and ASTM C702.

6 Fine aggregates shall be natural sand or manufactured crushed rock sand. Crushed rock

sand shall be the direct product of a manufacturing process, not the by-product of coarse

aggregate production.

7 Beach sand shall not be permitted for use in concrete mixes.

8 The use of clean Dune Sand, blended with coarser sand, may be permitted providing it can

be shown that the sand is free from contaminants. The use of local Dune sand shall be

preapproved by the Ministry of Environment.

9 Samples of aggregates shall be taken in accordance with the requirements of Table 1.1- Part

1.

10 Frequency of routine testing shall meet the requirements as listed in Section 2. Frequency of

testing may be increased by the engineer’s request if testing results show inconsistency, and

frequency may be reduced if approved by the engineer if materials are highly consistent.

11 Mineralogical tests are to be carried out as instructed by the Engineer.

12 No aggregate deliveries shall be made to the Site until the Engineer has approved the

samples as complying with this specification.

2.3 STORAGE AT CONTRACTOR PLANT

1 Aggregate shall be stored as follows:

(a) each nominal size of coarse aggregate and fine aggregate shall be kept separated and

clearly labelled at all times.

(b) The height of stockpiles shall be controlled to prevent harmful segregation and

breakage of the aggregate.

(c) stockpiles shall be on hard and clean surfaces with not more than 5 % slope

QCS


(d) contamination of the aggregates by the ground or other foreign matter shall be

effectively prevented at all times

(e) each heap of aggregate shall be capable of draining freely

(f) stockpiles shall be protected from direct sunlight

(g) unloading of aggregate shall be controlled to prevent harmful segregation and

breakage.

2 The Contractor shall maintain the stockpiles of coarse aggregate in separate gradings.

3 At the construction site, the preparation, location and size of any stockpile shall be approved

by the Engineer.

Table 2.1

Limits for Physical, Chemical and Mechanical Properties of Aggregates for Normal Concrete

No. Requirement

Test Methods1 Permissible Limits

BS / EN ASTM Fines Coarse

1. Grading 933-1 Standard Standard

2. Natural: materials finer than 0.063 mm. 933-1 3% max 2% max

Crushed rock: materials finer than 0.063mm.

7% max 2% max

3. Fines quality

a) Structural concrete

Sand Equivalent (%)

933-8

60% min2

b) Non-structural concrete Methylene blue adsorption value

3(0/2mm)

933-9

1.0 (g/kg) max

4. Clay lumps and friable particles C142 2% max 2% max

5. Lightweight pieces C123 0.5% max 0.5% max

6. Organic impurities for fine aggregates C40 Colour standard not darker than plate No. 3

4

NA

7. Water absorption (saturated surface dry)

1097-6 2.3% max 2.0% max

8. Particle density for normal weight concrete

1097-6 2.0 min 2.0 min

9. Shell Content: 933-7 3% max 3% max

10. Flakiness index

933-3 35% max

11. Acid-soluble chlorides: 1744-5

a) Reinforced and mass concrete 0.06% max 0.03% max

b) Prestressed concrete and steam cured structural concrete

5

0.01%

0.01%

QCS


No. Requirement

Test Methods1 Permissible Limits

BS / EN ASTM Fines Coarse

12. Acid-soluble sulphate 1744-1 0.4% max 0.3% max

13. Soundness by magnesium sulphate (5 cycles)

1367-2 15% max

15% max

14. Resistance to fragmentation: Los Angeles abrasion

1097-2 30% max

15. Drying shrinkage 1367-4 0.075% max

16. Potential reactivity: See Note 6 below

Notes:

1. Use of BS EN or relevant GSO standards.

2. If the Sand Equivalent value is less than 60% and greater than or equal to 50%, the sand shall be

considered non-harmful and is accepted provided that the Methylene Blue value is less than or equal to

1.0 (g/kg).

3. Not required when the fines content in the fine aggregate, or in the all-in aggregate, is 3% or less.

4. Organic impurities: use of a fine aggregate failing in the test is not prohibited, provided that:

a. The discoloration is due principally to the presence of small quantities of coal, lignite, or similar

discrete particles.

b. When tested for the effect of organic impurities on strength of mortar, the relative strength at 7

days, calculated in accordance with ASTM C87, is not less than 95 %.

5. If the chloride content is higher than 0.01% the following steps may be taken:

a- The aggregates may be washed by suitable water (Sec 5 Part 4) before mixing to lower the chloride content to the specified value (0.01%).

b- If the washing process does not reduce the chloride content to the required value, then the Acid Soluble Chloride content in the concrete ingredients (the sum of the contributions from the constituent materials) shall be tested as mentioned in BS 8500-2. The allowable Acid Soluble chloride content limit shall not exceed the values given in Section 5, Part 6, Para 6.5.3.

6. The alkali-aggregate reactivity shall be assessed at source in accordance with BS 206-1 and BS 8500-2. Certification shall be obtained from the aggregate source indicating absence of deleterious expansion of concrete due to alkali aggregate reactivity.

2.4 FINE AGGREGATE FOR CONCRETE AND MORTAR

1 Fine aggregate consist of natural clean sand, stone screenings or a combination and can be

produced from natural disintegration of rock or gravel and/or by the crushing of rock or gravel

or processing of manufactured aggregate or artificial, conforming to the requirements of

physical and chemical properties complying with Table 2.1 and subject to the Engineer's

acceptance.

2 Crushed fine aggregates may be blended with local washed sand provided that the final

aggregate complies with the requirements in Table 2.1.

3 The gradation of fine aggregate for concrete and mortar shall be in accordance with the

gradation designations in BS EN 12620 with BS PD 6682, EN 13139 , EN 998-1 , EN 998-2,

or relevant ACI and ASTM standards and codes of practice and subject to the Engineer’s

acceptance.

QCS


4 Each batch of aggregate delivered to the Site shall be kept separate from previous batches,

and shall be stored to allow for inspection and tests to be carried out.

5 Local natural sand shall be mechanically washed to remove salts and other impurities in

order to meet the specified requirements.

6 The storage area for the clean washed sand shall be shaded from the direct rays of the sun

and shall be screened for protection from dust. The area in the neighbourhood of

stockpile/mixing plant shall be watered as necessary, to reduce the rising of dust.

7 The usage of Dune sand shall be accepted as governed by the regulations of Qatar Ministry

of Environment and shall be:

(a) Not used for any reinforced concrete

(b) Used only for blocks, block mortar, plasters, soil cement, shotcrete and insulation

concrete.

2.5 COARSE AGGREGATE FOR CONCRETE

1 The coarse aggregate is granular material and may be natural, manufactured, recycled or a

combination. It shall be free from deleterious matter and conforming to the requirements of

physical and chemical properties in Table 2.1 as a minimum requirements and subject to the

Engineer's acceptance within BS EN 12620, BS PD 6682 or ASTM C33

2 For imported aggregate, Qatar Standards may publish more requirements and stringent limits

than specified in Table 2.1.

3 For other types of concrete mixes and subject to Engineer's acceptance, coarse aggregate

shall comply with the relevant BS EN or relevant ACI and ASTM standards and codes. The

nominal maximum size of coarse aggregate shall be not larger than: (a) 1/5 the narrowest

dimension between sides of forms, nor (b) 1/3 the depth of slab, nor (c) 3/4 the minimum

clear spacing between individual reinforcing bars or wires, bundles of bars, individual

tendons, bundled tendons, or ducts.

4 These limitations shall not apply if, in the judgment of the licensed design professional,

workability and methods of consolidation are such that concrete can be placed without

honeycombs or voids.

5 As requested by the Engineer, the Contractor shall mechanically wash the aggregates to

remove salts and other impurities in order to meet the requirements specified.

2.6 COMBINED AGGREGATE FOR CONCRETE

1 The material passing the 0.063mm sieve shall not exceed 3.0 % of the combined aggregate

(by weight). The combined aggregate gradation used in the work shall be as specified,

except when otherwise approved or directed by the Engineer.

2 Changes in the approved gradation shall not be made during the progress of the works

unless approved or directed by the Engineer.

QCS


2.7 WASHING AND PROCESSING

1 Where aggregates have been washed shortly before delivery to the Site, or if stockpiles have

been sprayed to cool them, samples of the aggregate shall be taken frequently to determine

the correct amount of water to add to the mix.

2.8 LIGHTWEIGHT AGGREGATES

1 Lightweight aggregates are those having particle densities not exceeding 2,000 kg/m3 or

loose bulk densities not exceeding 1200 kg/m3.

2 Lightweight aggregates include natural aggregate, aggregate manufactured from natural

materials and/or a by product of industrial processes, and some recycled aggregate.

3 Lightweight aggregates shall be in accordance with BS EN13055-1 and BS PD 6682-4, or

equivalent ASTM standards.

2.9 COARSE RECYCLED AGGREGATES

1 Excavation Waste (EW), coarse recycled aggregates (RA), and coarse recycled concrete

aggregates (RCA) shall meet with the requirements of Table 2.1, with the exception that

water absorption shall not exceed;

(a) 3% for structural concrete

(b) 4% for non-structural concrete.

2 For structural concrete EW and/or RCA may be used in designated concrete of maximum

C30. Its proportion shall be not more than a mass fraction of 20% of coarse aggregate (BS

8500-2 sec 6.2.2), except where approved by Qatar Standards to use a higher proportion.

3 For non-structural concrete, such as crash barriers and soakaways, EW and/or RCA may be

used in designated concrete of maximum C40. Its proportion shall be not more than a mass

fraction of 50% of coarse aggregate (BS 8500-2 sec 6.2.2), except where approved by Qatar

Standards to use a higher proportion.

4 For non-structural concrete RA may be used in designated concrete of maximum C25. Its

proportion shall be not more than a mass fraction of 20% of coarse aggregate (BS 8500-2

sec 6.2.2), except where approved by Qatar Standards to use a higher proportion.

5 When the composition of coarse RCA and coarse RA is tested in accordance with BS EN

933-11, the test result obtained for each type of particle shall not exceed the maximum value

specified in Table 2.2.

6 EW aggregate shall meet the same requirements for RCA, as given in Table 2.2.

QCS


Table 2.2

Requirements for coarse RCA and coarse RA, (mass fraction, %)

Type of

Aggregate

Requirement 1

Maximum

masonry

content

Maximum

fines

Maximum

lightweight

material 2

Maximum

Asphalt

Maximum

foreign

material

e.g. glass,

plastic,

metals

Maximum

acid soluble

sulphate

(SO3)

RCA 1, 3

5.0 5.0 0.5 5.0 1.0 1.0

RA 100 3 1.0 10.0 1.0 -4

1. Where the material to be used is obtained by crushing hardened concrete of known composition that has not been in use, e.g. surplus precast units or returned fresh concrete, and not contaminated during storage and processing, the only requirements are those for grading and maximum fines.

2. Material with a density less than 1,000 kg/m3

3. The provisions for coarse RCA may be applied to mixtures of natural coarse aggregates blended with the listed constituents.

4. The appropriate limit and test method needs to be determined on a case-by-case basis (see Note 6 to 4.3 of BS 8500-2).

7 The floating material (FL) content, as per BS EN 933-11, shall not exceed 5.0 cm3/kg.

8 RCA should be treated as highly reactive aggregate. The alkali contribution from RCA shall

be determined as given in BS 8500-2.

9 For manufacturing of masonry concrete blocks, the usage of recycled aggregates is

permitted up to 100% as given in Sec. 13 in accordance with ACI 555.

END OF PART

QCS

QCS 2014 Section 05: Concrete Page 1 Part 03: Cementitious Materials

3 CEMENTITIOUS MATERIALS................................................................................. 2

3.1 GENERAL ............................................................................................................... 2

3.1.1 Scope 2

3.1.2 References 2

3.1.3 Terms and Definitions: 3

3.2 SOURCE APPROVAL ............................................................................................. 3

3.3 SAMPLING .............................................................................................................. 3

3.4 QUALITY AND TESTING ........................................................................................ 3

3.5 DELIVERY, STORAGE AND HANDLING ................................................................ 4

QCS


3 CEMENTITIOUS MATERIALS

3.1 GENERAL

3.1.1 Scope

1 This Part covers the requirements for the testing and use of cement in structural concrete.


Part 6 Property Requirements

3.1.2 References


ASTM C10 ..................Standard specification for natural cement

ASTM C91 ..................Specification for Masonry cement

ASTM C114 ................Test methods for chemical analysis of Hydraulic Cement

ASTM C115, ...............Test method for fineness of Portland cement by the Turbidimeter

ASTM C150 ................Standard specification for Portland cement

ASTM C183 ................Standard Practice for sampling and the amount of testing of Hydraulic

cement

ASTM C188 ................Test method for density of Hydraulic cement

ASTM C186 ................Test method for heat of hydration of Hydraulic cement

ASTM C204 ................Test method for fineness of Hydraulic cement by air permeability

ASTM C348 ................Test method for flexural strength of Hydraulic cement mortar

ASTM C349 ................Test method for compressive strength of Hydraulic cement mortar

using portion of prism broken in flexure

ASTM C430 ................Test method for fineness of Hydraulic cement by the 45mm (No.325)

ASTM C595 ................Standard specification for blended Hydraulic cement

ASTM C618 ................Standard Specification for Coal Fly Ash and Raw or Calcined Natural

Pozzolan for Use in Concrete

ASTM C845 ................Specification for Expansive Hydraulic cement

ASTM C989 ..............Standard Specification for Slag Cement for Use in Concrete and

Mortars

ASTM C1157 ..............Standard performance specification for Hydraulic cement

ASTM C1240 .............Standard Specification for Silica Fume Used in Cementitious Mixtures

ASTM C1328 ..............Specification for plastic cement (Stucco)

ASTM C1329 ..............Specification for Mortar cement

BS 146 ........................Portland blast furnace cement

BS 1370 ......................Low heat Portland cement

BS 4027 ......................Sulphate-resisting Portland cement

BS EN 196, .................Methods for testing cement

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BS EN 197-1, .............Cement, Composition, specifications and conformity criteria for

common cements.

BS EN 197-4 .............Cement. Composition, specifications and conformity criteria for low

early strength blastfurnace cements

3.1.3 Terms and Definitions:

1 Cementitious Materials: Portland cement in combination with one or more of the following:

blended hydraulic cement, fly ash and other pozzolans, ground granulated blast-furnace slag,

silica fume and Metakaolin; subject to compliance with requirements of this specification.

2 PC: shall mean Portland cement or CEM I.

3 FA or PFA: shall mean fly ash or pulverised fuel ash.

4 GGBS: shall mean ground granulated blast furnace slag.

3.2 SOURCE APPROVAL

1 The Contractor shall submit to the Engineer for approval full details of the proposed source of

cement. These sources of cement supply shall be regularly and thoroughly investigated to

ensure that the quality of the material supply is satisfactory and that it does not deteriorate

during the performance of the project.

2 The cement source shall not be changed without the Engineer's acceptance.

3 The Contractor shall supply the Engineer with the manufacturer’s test certificates certifying

that the cement is in compliance with the relevant standards.

4 For imported cement the manufacturer’s test certificates shall be provided with each

consignment. The Contractor shall submit to the Engineer the date of manufacture and proof

that the specifications have been complied with, certified by an independent agency in the

country of origin.

5 Cement manufacturers shall label their packaging and delivery documents and shall provide,

where applicable, information on the packing/dispatch date, storage conditions and the

storage period appropriate to maintaining the activity of any reducing agent and to keeping

the content of soluble chromium (VI) below the 2 ppm limit. The Engineer has the right to test

the cement for presence of chromium at the contractor’s expense.

3.3 SAMPLING

1 The methods of obtaining samples of cement for testing shall be carried out as described in

EN 196 or ASTM C183


1 The cementitious material shall fully comply with the relevant standard(s) from the following

list:

ASTM C150 ................Standard specification for Portland cement

ASTM C595 ................Standard specification for blended Hydraulic cement

http://shop.bsigroup.com/en/ProductDetail/?pid=000000000030050210



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ASTM C618 ...............Standard specification for coal fly ash and raw natural pozzolan for use

in concrete

ASTM C989 ...............Standard specification for ground granulated blastfurnace slag for use

in concrete and mortars

ASTM C1157 ..............Standard performance specification for Hydraulic cement

ASTM C1240 ..............Standard specification for silica fume used in cementitious mixtures

BS 146 ........................Portland-blast furnace cement

BS 1370 ......................Low heat Portland cement

BS 4027 ......................Sulphate-resisting Portland cement

BS EN 197-1, ............minimum grade 42.5

BS EN 450 .................Fly ash for concrete.

BS EN 15167 .............Ground granulated blastfurnace slag for use in concrete, mortar and

grouts.

EN 12363 ..................Silica fume for concrete.

Relevant GSO

2 The water-soluble chromium (VI) content shall not exceed 2ppm (0,0002%) by total dry weight of cementitious materials.

3.5 DELIVERY, STORAGE AND HANDLING

1 Cement shall be delivered to the Site in sealed and branded bags, or in the manufacturer’s

containers, bearing the manufacturer’s name, cement type and date of manufacture, in

batches not exceeding 100 tons.

2 Cement shall be stored at the site in such a manner, as to prevent its deterioration, intrusion

of moisture and foreign matter. It must be kept dry at all times. Immediately upon arrival at

the Site the Contractor shall store the cement in

(a) bins or silos designed for the purpose. It shall be tight and provide for free movement

to discharge opening, or

(b) dry, weather tight and properly ventilated structures with floors raised a minimum of

450 mm above the ground with adequate provision to prevent absorption of moisture.

3 All storage facilities shall be subject to the approval of the Engineer, and shall be such as to

permit easy access for inspection and identification. Prolonged storage of cement at site is to

be avoided.

4 For bagged cement, each consignment of cement shall be kept separately, and the

Contractor shall use the consignments in the order in which they are received.

5 The Contractor shall keep records of the various consignments of cement in store, giving

quantities received and used, and the sections of the work in which the cement has been

used, on a daily basis and make a weekly return to the Engineer accordingly. Cement used in

the Works shall be free flowing and free from lumps.

6 In no case shall bagged cement be stored in stacks more than eight bags high.

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7 A free passage of at least 1 m shall be left between the cement and the side walls of the

structure.

8 Different types of cement shall be kept in clearly marked separate storage facilities.

9 Cement delivered to Site in drums or bags by the supplier or manufacturer shall be stored in

the drums or bags until used in the Works.

10 Any cement in drums or bags which have been opened shall be used immediately.

11 Cement that has partially or fully caked in storage will not be permitted in work and shall be

immediately removed from the storage area. Any bag or package or sample of cement which

has been damaged, or rebagged or in any way has deteriorated shall be rejected either as an

individual bag or package or as the whole consignment in which such bag, package or

sample is contained, as advised by the Engineer.

12 Where Site limitations preclude the storage of cement on Site, cement shall be stored at a

central location and shall be delivered daily as required to specific job sites.

13 The Contractor shall provide weighing machines which shall be kept permanently in each

shed for checking the weight of the bags or barrels of cement. The weighing machines shall

be calibrated by an independent agency. The Engineer shall have access at all times to the

cement storage sheds.

14 During transport and storage the cement shall be fully protected from all weather elements.

15 Any consignment of cement not used within two months from the date of manufacture and

cement which in the opinion of the Engineer is of doubtful quality shall not be used in the

Works until it has been retested and test result sheets showing that it complies in all respects

with the specification and relevant standards have been delivered to the Engineer.

16 Cement stored for longer than 28 days shall be tested for “loss on ignition" prior to use to

check for deterioration, and any cement which fails the test shall not be used in the works.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 04: Water

4 WATER ................................................................................................................... 2

4.1 GENERAL ............................................................................................................... 2

4.1.1 Scope 2

4.1.2 References 2

4.2 QUALITY OF WATER ............................................................................................. 3

4.2.1 General 3

4.2.2 pH of Water 3

4.2.3 Permissible Temperatures 3

4.2.4 Supply and Storage 3

4.3 TESTING AND SAMPLING ..................................................................................... 3

4.3.2 Health and Safety 5

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4 WATER

4.1 GENERAL

4.1.1 Scope

1 This Part includes water used for concrete mixtures, washing of aggregates and equipment,

wetting of surfaces or ponding during curing or for wetting formwork and washing

reinforcement.


This Section

Part 2, .............. Aggregates


Part 9, .............. Formwork

Part 10, ............ Curing

Part 11, ............ Reinforcement

4.1.2 References


ASTM C109 ................test Method for Compressive Strength of Hydraulic Cement Mortars

(using 2-in or 50 mm Cube Specimens)

BS 1377 ......................Methods of test for soils for civil engineering purposes.

BS 2690 ......................Methods of testing water used in industry

BS 6068 ......................Water quality

BS EN ISO 9963-1 .....Determination of total and composite alkalinity

BS EN ISO 9963-2 .....Determination of carbonate alkalinity

EN 196-1 ....................Determination of strength

EN 196-2 ....................Methods of testing cement - Part 2: Chemical analysis of cement

EN 196-3 ....................Determination of setting time and soundness

EN 1008 .....................Mixing water for concrete, Specification for sampling, testing and

assessing the suitability of water, including water recovered from

processes in the concrete industry, as mixing water for concrete

SM 5220 B ................. Chemical Oxygen Demand (COD)

SM 4500 ....................Standard Methods for the Examination of Water and Wastewater

ISO 7890 ...............Water quality -- Determination of nitrate -- Part 1: 2,6-Dimethylphenol

spectrometric method

SM 3125B (ICP/MS) ...Metals by Inductively Coupled Plasma/Mass Spectrometry

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4.2 QUALITY OF WATER

4.2.1 General

1 Potable water is suitable for use in concrete, while water of other origin such as underground

water, natural surface water, recovered water, as well as municipal treated water or mixed

water shall be tested to prove that its quality shall conform to water quality requirements as

given below in 4.3.

2 On site, where a permit is issued for Municipal Treated Effluent use for concrete, the effluent

shall be treated by tertiary treatment stage: Reverse Osmosis (R.O.), and disinfection

(Ultraviolet Radiation, or ozonation).

3 The water shall be examined in accordance with the test procedures stated in Table 1, EN

1008. Water not conforming to one or more of the requirements in Table 1, EN 1008 may be

used only, if it can be shown to be suitable for use in concrete, in accordance with the

physical tests of Table 1 below.

4 The site health and safety services and Treated Effluent Quality shall fulfil the requirements

of 5

4.2.2 pH of Water

1 The pH of water used in concrete works shall be as shown in Table 4.2.

4.2.3 Permissible Temperatures

1 Temperature of water for concrete shall not be less than 5 °C and not more than 40 °C

2 Water may be cooled to not less than 5 °C by the gradual addition of chilled water or ice as

follows:

(a) no ice particles shall be present in the mix

(b) alternatively, flaked ice may be used

(c) ice to be used shall be crushed and shall be a product of frozen water which

complies with the acceptance criteria of Tables 4.1 and 4.2 and 4.3.

3 Every effort should be made to protect water pipes and tanks from the sun; e.g., burying,

shading, insulation or painting white.

4.2.4 Supply and Storage

1 The Contractor shall make his own arrangements and obtain the approval of the Engineer for

the supply of water.

2 Storage of water should be such that contamination is prevented from occurring. Any

measures taken to avoid contamination of the water shall be to the approval of the Engineer.

4.3 TESTING AND SAMPLING

1 Whenever required to do so by the Engineer, the Contractor shall take samples of the water

being used, or which it is proposed to use, for mixing concrete and test them for quality.

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2 Samples of water of not less than 5 l shall be taken, sealed and sent for testing at an

approved independent laboratory, prior to the approval of any water source, and whenever

the sources of water is changed periodically during the continuance of its use.

3 Water of questionable quality should comply with the physical tests of Table 4.1 and chemical

limitations listed in Table 4.2 & Table 4.3.

4 No source of water shall be used until the required tests have demonstrated its suitability for

concreting.

5 The use of water from a municipal or government supply does not preclude the requirement

for testing.

Table 4.1

Acceptance Criteria and Physical Tests for Mixing Water

Test Method Limits

Compressive strength at 7 d, min % of control EN 196-1 90 %

Setting time, max. deviation from control, (h:min) EN 196-3 from 1:00 early to 1:30 later

Table 4.2

Chemical Limitations for Mixing Water

Parameter Test Method Maximum Limit,

mg/l

(a) Chloride (as CI) (a-1) for Prestressed concrete. (a-2) for reinforced concrete. (a-3) for concrete without reinforcement.

BS 6068-1.37 (ISO 9297)

500

1000

4500

(b) Sulphates (as SO42-

) EN 196-2

2000

(c) Alkali (c-1) Alkali carbonates and bicarbonates (c-2) Alkali equivalent sodium oxides

BS 6068-2.51

BS EN ISO 9963-1 BS EN ISO 9963-2

EN 196-2

500

1500

(d) Total dissolved ions, including

a, b and c above (d-1) for prestressed concrete (d-2) reinforced concrete. (d-3) for concrete without reinforcement.

BS 1377 : Part 3

1000 2000 5000

(e) pH BS 6068-2.50 6.5 - 9.0

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Table 4.3

Maximum limit of Harmful Contaminants

Parameter Test Method Maximum Limit, mg/l

COD SM 5220 B 50

Phosphate; expressed as PO4 - P SM 4500 P B, C, SM 4500

PD by subtraction 30

Nitrate; expressed as NO3- -N ISO 7890-1 100

Lead; expressed as Pb 2+

SM 3125B (ICP/MS) 100

Zinc; expressed as Zn2+

SM 3125B (ICP/MS) 100

SM: Standards Methods for the Examination of Water and Wastewater.

4.3.2 Health and Safety

1 On site, where a permit is issued for Municipal Treated Water use in construction works, the

effluent should be treated by tertiary treatment stage including filtration and disinfectant

(Chlorine alone, or Ultraviolet Radiation, or ozonation). Furthermore, the following site health

and safety services and the Treated Effluent Quality shall be fulfilled:

(a) Residual chlorine level shall be within the range of 0.5 – 1.0 mg/l. For water to be used

for concrete, the disinfectant shall be Ultraviolet Radiation, or ozonation.

(b) Coliform level shall fulfil one of the following:

(i) Fecal Coliform < 200 CFU/100 ml, in case there is no direct exposure on site

labour.

(ii) Total Coliform < 23 CFU/100 ml, in case there is direct exposure on site labour.

(c) The site shall be facilitated by health and safety guidelines signs, where it is indicated

by Arabic, English, and any other languages where there are 5 workers or more on the

site, that “Water not for Human Consumption”

(d) The site shall be facilitated by health and safety equipment, as well as, personal health

and safety protection equipment.

(e) Labour shall follow health and safety guidelines and instructions and use their health

and safety personal protection equibment.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 05: Admixtures

5 ADMIXTURES ......................................................................................................... 2

5.1 GENERAL ............................................................................................................... 2

5.1.1 Scope 2

5.1.2 References 2

5.1.3 Definitions 2

5.1.4 Submittals 2

5.2 USE OF ADMIXTURES ........................................................................................... 3

5.2.1 General 3

5.2.2 Trials 3

5.3 WATER PROOFING ADMIXTURES ....................................................................... 3

5.3.1 General 3

5.3.2 Water resisting admixtures 4

5.3.3 Permeability reducing admixture 4

5.3.4 Submittals 4

5.3.5 General 4

5.3.6 Organic Corrosion Inhibitors 4

5.3.7 Inorganic Corrosion Inhibitors 5

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5 ADMIXTURES

5.1 GENERAL

5.1.1 Scope

1 This Part includes materials added to the concrete materials during mixing.


This Section

Part 1 ............... General

Part 6 ............... Property Requirements

Part 7 ............... Concrete Plants

Part 16 ............. Miscellaneous

5.1.2 References

1 The following standards and other documents are referred to in this Part:

ACI 212.3R-10 ............Report on Chemical Admixtures for Concrete

ACI 302 ......................Guide for Concrete Floor and Slab Construction

ACI 305 ......................Hot Weather Concreting

ACI 308 ......................Standard Practice for Curing Concrete

ASTM C494, ...............Standard Specification for Chemical Admixtures for Concrete

ASTM C1582, .............Standard Specification for Admixtures to Inhibit Chloride-Induced

Corrosion of Reinforcing Steel in Concrete

BS EN 934 ..................Admixtures for concrete, mortar and grout (Parts: 2, 6)

BS EN 196, ................Methods of testing cement

BS EN 14889 .............Fibres for concrete Polymer fibres. Definitions, specifications and

conformity

NSF ............................ Standard 61

5.1.3 Definitions

1 Admixtures are materials added during the mixing process of concrete to modify the

properties of the concrete mix in the fresh and/or hardened state.

5.1.4 Submittals

1 In addition to the specified general requirements for approval of materials, approval of

admixtures shall be subject to extensive trials to demonstrate the suitability, adequacy of

dosing arrangements and performance.

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5.2 USE OF ADMIXTURES

5.2.1 General

1 Admixtures are materials added to the concrete materials during the mixing process to

modify its properties in the fresh and/or hardened state.

2 Where approved and or directed by the Engineer, admixtures shall be used as a means of:

(a) enhancing concrete durability

(b) increasing workability of the concrete without increasing the water:cement ratio

(c) controlling retardation and setting time.

3 Admixtures shall comply with the following BS EN 934 – 2 requirements or the equivalent

ASTM C494:

(a) water reducing/plasicizing admixture

(b) high range water reducing/plasticizer admixture

(c) set retarding admixtures

4 The methods and the quantities of admixture used shall be in accordance with the

manufacturer’s instruction and subject to the Engineer’s approval after evaluation in trial

mixes and shall in no way limit the Contractor’s obligations under the Contract to produce

concrete with the specified strength, workability and durability.

5 The effects of accidental overdose of the admixture and measure to be taken if an overdose

occurs shall be provided by the Contractor to the Engineer.

6 No admixtures containing chlorides shall be used. In particular, the use of acceleration

admixtures containing calcium chloride shall not be used.

7 The use of the admixtures shall be controlled; i.e., strict quality control to ensure correct

dosages as prescribed by the manufacturer and justified by trial mixes to be used. A

calibrated dispenser or flowmeter shall be used for the addition of the admixture.

5.2.2 Trials

1 In addition to the standard requirements for the approval of materials, approval of admixtures

shall be subject to extensive trials to demonstrate the suitability, adequacy of dosing

arrangements and performance, when a proven history of performance cannot be provided to

the satisfaction of the Engineer.

5.3 WATER PROOFING ADMIXTURES

5.3.1 General

1 The admixture shall be suitable for use in the Gulf condition, and specially formulated for

higher ambient temperature.

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2 The admixture shall be added as per manufacturer’s datasheet. Approved third party

laboratory verification shall be conducted prior to use of material for the works. The

manufacturer’s technical representative shall be present to ensure proper dosage of

admixture during the trial mix.

5.3.2 Water resisting admixtures

1 Water resisting admixtures may be used with the permission of the Engineer and shall

comply with the requirements of BS EN 934-2.

2 The admixture is to be added as per the Manufacturer’s supplier data sheet at the time of

mixing. An approved lab verification shall be made prior to use,

5.3.3 Permeability reducing admixture

1 The admixture shall be a permeability reducing admixture for Non-Hydrostatic Conditions

(PRAN) and for hydrostatic conditions (PRAH) as indicated by ACI 212.3R-10, or crystalline

waterproofing admixture.

2 For PRAH, independent testing shall be performed according to NSF Standard 61 and

approval for use of waterproofing material on structures holding potable water shall be

evidenced by NSF certification.

5.3.4 Submittals

1 The Contractor shall submit manufacturers' specifications, installation instructions and other

data to show compliance with the requirements of this part of the specification and the

Contract Documents.

2 The Contractor shall submit comprehensive test results for the water proofing admixture as

per the tests in the specification, and evidence of their ability to meet all the requirements

specified.

3 The Contractor shall submit a guarantee for the water proofing admixture. The guarantee

shall be worded to reflect the required performance of the material and shall be approved by

the Engineer.

4 CORROSION INHIBITING ADMIXTURES

5.3.5 General

1 Where reinforced concrete structures are exposed to aggressive environment such as

underground and marine structures, the use of a corrosion inhibiting admixture shall be used.

2 Corrosion Inhibiting Admixtures shall comply with ASTM C1582 Standard Specification for

Admixtures to Inhibit Chloride-Induced Corrosion of Reinforcing Steel in Concrete.

5.3.6 Organic Corrosion Inhibitors

1 The admixture shall be based on either aqueous emulsion of amines and esters or amine

carboxylates and shall be capable of forming a protective corrosion resistant film around the

steel reinforcement.

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2 The corrosion inhibitor shall be capable of effecting protection to the steel where concrete

has cracked and allows access to the elements responsible for corrosion.

3 Organic corrosion inhibitors have a fixed dosage rate independent of chloride levels and shall

be incorporated at the dosage rate recommended and tested by the Manufacturer.

5.3.7 Inorganic Corrosion Inhibitors

1 Inorganic corrosion inhibitors shall be based on calcium nitrites capable of oxidizing steel to a

more stable form increasing its passivity in the presence of chlorides.

2 Dosage of inorganic corrosion inhibitors ranges from 10 to 30L/m3 depending on the

expected chloride levels as defined by ACI 212 Table 13.1.

END OF PART

QCS

QCS 2014 Section 05: Concrete Page 1 Part 06: Property Requirements

6 PROPERTY REQUIREMENTS ............................................................................... 2

6.1 GENERAL ............................................................................................................... 2

6.1.1 Scope 2

6.1.2 References 2

6.1.3 Definitions: 6

6.1.4 Submittals 7

6.2 EXPOSURE CLASSES ......................................................................................... 10

6.2.1 General 10

6.2.2 Reinforcement corrosion and sulphate classes 10

6.3 FRESH CONCRETE ............................................................................................. 12

6.3.1 General 12

6.4 GRADES OF CONCRETE..................................................................................... 13

6.5 DURABILITY REQUIREMENTS ............................................................................ 13

6.5.1 General 13

6.5.2 Maximum acid soluble chloride content 14

6.5.3 Type of cementitious material 14

6.5.4 Resistance to alkali-silica reaction 15

6.5.5 Recommendations to resist reinforcement corrosion 15

6.5.6 Recommendations to resist sulphate attack 16

6.5.7 Durability-Related Properties 16

6.6 DESIGN OF CONCRETE MIXES .......................................................................... 17

6.6.1 Concrete 18

6.7 TRIAL MIXES ........................................................................................................ 25

6.8 QUALITY AND TESTING ...................................................................................... 27

6.8.1 General 27

6.8.2 Tests for Concrete 27

6.8.3 Hardened Tests for Fiber-Reinforced Concrete 29

6.8.4 Quality Control charts 29

6.9 WORKS TEST CUBES ......................................................................................... 30

6.10 REJECTION OF CONCRETE MIXES ................................................................... 30

6.10.1 Rejection of Concrete Mixes: 30

6.10.2 Unsatisfactory Concrete Works 31

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6 PROPERTY REQUIREMENTS

6.1 GENERAL

6.1.1 Scope

1 This Part includes Grades 15 MPa and above of concrete to be used in the civil works, with

the requirements for workability, permeability, and drying shrinkage.


This Section

Part 2, ........... Aggregates

Part 3, ........... Cementitious Materials

Part 4, ............ Water

Part 5, ........... Admixtures

Part 7, ............ Concrete Plants

Part 8, ........... Transportation and Placing of Concrete

Part 9, .............. Formwork

Part 13, ............ Inspection and Testing of Hardened Concrete

6.1.2 References

1 The following standards are referred to in this Part. The designer along with contractor are

responsible to use the latest update standard as published by the organization:

ACI 207.1R ................. Guide to Mass Concrete

ACI 207.2R ................. Report on Thermal and Volume Change Effects on Cracking of Mass

Concrete

ACI 207.5R ................. Roller - Compacted mass concrete

ACI 213, ..................... Guide for Structural Lightweight-Aggregate Concrete

ACI 214, ..................... Evaluation of Strength Test Results of Concrete

ACI 221, ..................... Guide for Use of Normal Weight and Heavyweight Aggregates in

Concrete

ACI 237R 07 .............. Self Consolidating Concrete

ACI 301, ..................... Specifications for Structural Concrete

ACI 304, ..................... Guide for Measuring, Mixing, Transporting, and Placing Concrete

ACI 304.2, .................. Placing Concrete by Pumping Methods

ACI 318, ..................... Metric Building Code Requirements for Structural Concrete &

Commentary

ACI 506, .................... Guide to Shotcrete

ACI 506.1, .................. Guide to Fiber-Reinforced Shotcrete

ACI 506.2, .................. Specification for Shotcrete

ACI 555, ..................... Removal and Reuse of Hardened Concrete

ASTM A 820, .............. Specification for Steel Fibers for Fiber-Reinforced Concrete

ASTM C 31, ................ Practice for making and curing concrete test specimens in the field

ASTM C 33, ............... Specification for Concrete Aggregates

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ASTM C 39, ................ Test Method for Compressive Strength of Cylindrical Concrete

Specimens

ASTM C 42, ................ Test Method for Obtaining and Testing Drilled Cores and Sawed

Beams of Concrete

ASTM C 94, ................ Specification for Ready-Mixed Concrete

ASTM C192, ............... Practice for Making and Curing Concrete Test Specimens in the

Laboratory

ASTM E 119, .............. Test Methods for Fire Tests of Building Construction and Materials

ASTM C 138, .............. Test Method for Density (Unit Weight), Yield, and Air Content

(Gravimetric) of Concrete

ASTM C 150, ............. Specification for Portland Cement

ASTM C 172, .............. Practice for Sampling Freshly Mixed Concrete

ASTM C 173, .............. Test Method for Air Content of Freshly Mixed Concrete by the

Volumetric Method

ASTM C 231 ............... Test Method for Air Content of Freshly Mixed Concrete by the

Pressure Method

ASTM C 232, ............. Test Methods for Bleeding of Concrete

ASTM C 311, ............. Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans

for Use in Portland-Cement Concrete

ASTM C 387, .............. Specification for Packaged, Dry, Combined Materials for Mortar and

Concrete

ASTM C 597, .............. Test Method for Pulse Velocity through Concrete

ASTM C 617, ............. Practice for Capping Cylindrical Concrete Specimens

ASTM C 618, ............. Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan

for Use in Concrete

ASTM C 637, .............. Specification for Aggregates for Radiation-Shielding Concrete

ASTM C 638, ............. Descriptive Nonmenclature of Constituents of Aggregates for

Radiation-Shielding Concrete

ASTM C 803, ............. Test Method for Penetration Resistance of Hardened Concrete

ASTM C 805, ............. Test Method for Rebound Number of Hardened Concrete

ASTM C 856, ............. Practice for Petrographic Examination of Hardened Concrete

ASTM C 900, ............. Test Method for Pullout Strength of Hardened Concrete

ASTM C 989, .............. Standard Specification for Slag Cement for Use in Concrete and

Mortars

ASTM C 1018, ............ Test Method for Flexural Toughness and First-Crack Strength of Fiber-

Reinforced Concrete

ASTM C 1116, ........... Specification for Fiber-Reinforced Concrete

ASTM C 1140, ............ Practice for Preparing and Testing Specimens from Shotcrete Test

Panels

ASTM C 1152 ............. Standard Test Method for Acid-Soluble Chloride in Morter and

Concrete.

ASTM C 1218 ............. Standard Test Method for Water-Soluble Chloride in Morter and

Concrete.

ASTM C 1231, ............ Practice for Use of Unbonded Caps in Determination of Compressive

Strength of Hardened Concrete Cylinders

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ASTM C 1240, ............ Specification for Silica Fume Used in Cementitious Mixtures

ASTM C 1385, ............ Practice for Sampling Materials for Shotcrete

ASTM C 1399, ............ Test Method for Obtaining Average Residual-Strength of Fiber-

Reinforced Concrete

ASTM C 1480, ............ Specification for Packaged, Pre-Blended, Dry, Combined Materials for

Use in Wet or Dry Shotcrete Application

ASTM C 1550, ............ Test Method for Flexural Toughness of Fiber Reinforced Concrete

(Using Centrally Loaded Round Panel)

ASTM C 1604, ............ Test Method for Obtaining and Testing Drilled Cores of Shotcrete

ASTM C 1609, ............ Test Method for Flexural Performance of Fiber-Reinforced Concrete

(Using Beam With Third-Point Loading)

ASTM C 1611, ............ Test Method for Slump Flow of Self-Compacting Concrete

ASTM C 1666, ............ Specification for Alkali Resistant (AR) Glass Fiber for GFRC and

Fiber-Reinforced Concrete and Cement

ASTM D 5759, ............ Guide for Characterization of Coal Fly Ash and Clean Coal

Combustion Fly Ash for Potential Uses

ASTM D 6942, ............ Test Method for Stability of Cellulose Fibers in Alkaline Environments

BRE digest 433, ......... Recycled Aggregates

BS 4027, .................... Specification for Sulphate-Resisting Portland Cement

BS 6073-2:2008, ........ Precast concrete masonry units. Guide for specifying precast concrete

masonry units

BS 8500, .................... Concrete, Complementary British Standard to BS EN 206-1.

BS 8666, ..................... Specification for scheduling, dimensioning, bending and cutting of

steel reinforcement for concrete

BS EN 206-1, ............ Concrete. Specification, Performance, Production And Conformity

BS EN 450, ................. Fly Ash for Concrete. Definition, Specifications And Conformity Criteria

BS EN 771-3, ............. Specification for masonry units. Aggregate concrete masonry units

(dense and light-weight aggregates

BS EN 772-2, ............. Methods of test for masonry units. Determination of percentage area

of voids in masonry units (by paper indentation)

BS EN 12350, ............. Testing Fresh Concrete

BS EN 12350-1, ......... Testing fresh concrete - Part 1: Sampling

BS EN 12350-2, ......... Testing fresh concrete - Part 2: Slump test

BS EN 12350-3, ......... Testing fresh concrete - Part 3: Vebe test

BS EN 12350-4, ......... Testing fresh concrete - Part 4: Degree of compactability

BS EN 12350-5, ......... Testing fresh concrete - Part 5: Flow table test

BS EN 12350-6, ......... Testing fresh concrete - Part 6: Density

BS EN 12350-7, ......... Testing fresh concrete - Part 7: Air content - Pressure methods

BS EN 12390, ............. Testing Hardened Concrete

BS EN 12390-1, ......... Testing hardened concrete - Part 1: Shape, dimensions and other

requirements for specimens and moulds

BS EN 12390-2, ......... Testing hardened concrete - Part 2: Making and curing specimens for

strength tests

QCS


BS EN 12390-3, ......... Testing hardened concrete - Part 3: Compressive strength of test

specimens

BS EN 12390-4, ......... Testing hardened concrete - Part 4: Compressive strength -

Specification for testing machines

BS EN 12390-5, ......... Testing hardened concrete - Part 5: Flexural strength of test

specimens

BS EN 12390-6, ......... Testing hardened concrete - Part 6: Tensile splitting strength of test

specimens

BS EN 12390-7, ......... Testing hardened concrete - Part 7: Density of hardened concrete

BS EN 12390-8, ......... Testing hardened concrete - Part 8: Depth of penetration of water

under pressure

BS EN 12620, ............. Aggregate For Concrete

BS EN 15167 ............. Ground Granulated Blast Furnace Slag For Use In Concrete, Mortar

And Grout. Conformity Evaluation

BS EN 1744, .............. Tests For Chemical Properties Of Aggregates

BS EN 1992-3:2006 ... Eurocode 2. Design of concrete structures. Liquid retaining and

containing structures

BS EN 1992-3:2006 ... UK National Annex to Eurocode 2. Design of concrete structures.

Liquid retaining and containment structures

BS PD 6682-1, ........... Aggregates for Concrete. Guidance on the Use of BS EN 12620

Concrete Society Report No. 31, Permeability testing of site concrete

EN 1011, .................... Welding. Recommendation for welding of metallic materials

EN 1992-1-1, .............. Eurocode 2: Design of concrete structures. General rules and rules for

buildings


GSO ISO 1920-2 ........ Testing of concrete – part 2: properties of fresh concrete

GSO ISO 1920-3 ........ Testing of concrete – part 3: Making and curing test specimens.

GSO ISO 1920-4 ....... Testing of concrete – part 4: strength of hardened concrete.

GSO ISO 1920-5 ....... Testing of concrete – part 5: properties hardened concrete other than

strength.

GSO ISO 1920-6 ........ Testing of concrete – part 6: sampling, preparing and testing of

concrete core .

GSO ISO 1920-7 ....... Testing of concrete – part 7: Non –destructive test on hardened

concrete.

ISO 1920-8 ................. Testing of concrete -- Part 8: Determination of drying shrinkage of

concrete for samples prepared in the field or in the laboratory

ISO 1920-9 ................. Testing of concrete -- Part 9: Determination of creep of concrete

cylinders in compression

ISO 1920-10 ............... Testing of concrete -- Part 10: Determination of static modulus of

elasticity in compression

http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=41967



QCS


CSTR11...................... Concrete core testing – The concrete Society

RILEM CPC 11.3 ....... Absorption of water by immersion under vacuum

The Concrete Society CS163. Guide to the design of concrete structures in the Arabian Peninsula.

The European Guidelines for Self-Compacting Concrete Specification, Production and Use

6.1.3 Definitions:

1 Exposure conditions will apply as follows:

(a) Class X0: No risk of corrosion or attack. Non saline conditions. Blinding concrete, non-reinforced concrete or slab on ground.

(b) Class X1: Mild exposure – Non saline conditions (dry or wet, rarely dry) External concrete at least 3m above ground level, internal concrete in dry conditions, concrete permanently submerged in non-saline water or non-aggressive groundwater.

(c) Class X2: Moderate exposure – Non saline conditions (Cyclic wet and dry). External reinforced concrete less than 3m above ground level, water-retaining structures exposed to fluctuating water levels.

(d) Class X3: Aggressive exposure – Permanently submerged or wet (rarely dry) Concrete in contact with groundwater including capillary rise zone, concrete containing or permanently exposed to saline water.

(e) Class X4: Severe exposure – Moderate humidity External concrete within 1km from the sea or in contact with high saline water table or sabkhas. Concrete not affected by condensation, irrigation or leakage, which are more than 3m above ground level.

(f) Class X5: Extreme exposure – Cyclic wet and dry, external concrete within 1km from the sea or in contact with high saline groundwater or sabkhas. Concrete affected by condensation, irrigation or leakage, which are less than 3m above ground level or within capillary zone. Concrete surfaces exposed to sea water splash or in sea water tidal zone.

(g) Sulphate exposure classes S1 to S4: the exposure classes are related to sulphate attack in relation to sulphate and pH of the ground water.

2 Concrete is a mixture (mix) of cementitious materials, coarse and fine aggregate, and water, with or without admixtures, which develops its properties by cement hydration.

3 "Cementitious Materials": Portland cement in combination with one or more of the following: blended hydraulic cement, fly ash and other pozzolans, ground granulated blast-furnace slag and silica fume; subject to compliance with requirements of this specification.

4 “Water/Cementitious Ratio” shall mean the ratio between the total weight of water in the concrete (less the water absorbed by the aggregate) and the weight of cementitious materials, expressed as a decimal fraction.

5 “Admixtures” shall mean a material other than water, aggregate, cementitious materials or fiber reinforcement, used as an ingredient of concrete or mortar. Admixtures are added during the mixing process of concrete to modify the properties of the concrete mix in the fresh and/or hardened state.

6 “Hot Weather” shall mean any combination of the following conditions that tends to impair the quality of freshly mixed or hardened concrete by accelerating the rate of moisture loss and rate of cement hydration, or otherwise causing detrimental results such as: a. High ambient temperature (when the shade temperature is above 40 deg C on a rising thermometer, 43 deg C on a falling thermometer), b. High concrete temperature, c. Low relative humidity, d. High wind speed and e. whenever the rate of evaporation exceeds 0.75 kg/m

2/h

QCS


7 “Mass concrete” is defined as any volume of concrete with dimensions large enough to require that measures be taken to cope with generation of heat form hydration of the cement and attendant volume change to minimize cracking. Reinforced Massive concrete structures include pile caps, transfer plates, and structural members where the least dimension exceeds 1.5 meters.

8 “Coarse Aggregate” shall be considered as that size passing a 20mm sieve (or larger sieve size) and predominately retained on a 4mm sieve.

9 “Fine Aggregate” shall be considered as that size predominately passing a 4mm sieve and predominately retained on a 0.063mm size.

10 “PC” shall mean Portland cement or CEM I.

11 “FA” shall mean pulverised fuel ash or fly ash.

12 “GGBS” shall mean ground granulated blastfurnace slag.

13 “SF” shall mean silica fume. Other names are condensed silica fume and microsilica

14 “Gap-graded aggregate” shall mean graded aggregate without one or more of the intermediate sizes.

15 “Single-size aggregate” shall mean aggregates containing a major proportion of particles of one sieve size.

16 “Target Mean Strength” shall mean the specified characteristic strength plus the margin.

17 “Margin” shall mean the difference between the specified characteristic strength and the target mean strength.

18 “Acceptable or Accepted” shall mean acceptable or accepted by the Engineer.

19 “Approval or Approved” shall mean approval from the Engineer.

20 “All-in” aggregate shall mean the materials composed of a mixture of coarse and fine aggregates.

21 Self-Compacting Concrete (SCC): concrete that is able to flow and consolidate under its own weight, completely fill the formwork even in the presence of dense reinforcement, whilst maintaining homogeneity and without the need for any additional compaction.

6.1.4 Submittals

1 The Contractor shall submit details of mix designs to the Engineer for approval.

2 Material Safety Data Sheet MSDS or equivalent for all products. test results and other information as required to prove compliance with the specification shall be submitted to the Engineer for approval according to the relevant sections of QCS on at least the following products

3 Cement:

(a) Recent independent test results acceptable to the Engineer confirming compliance with the specified requirements and referenced standards.

(b) Manufacturer's certificates shall also be supplied for each batch of production of cement or on a weekly basis, whichever is more frequent, certifying compliance with the BS EN 197 or other equivalent standard.

QCS


(c) The early compressive strength of each consignment of cement shall conform to the requirements of QCS part 3 at the independent site laboratory. Deviation of more than 10% from either the previous consignment value or the rolling average shall be immediately reported to the Engineer. Testing at an independent laboratory shall be as instructed by the Engineer.

4 GGBS:


(b) Manufacturer's certificates with all information necessary to verify compliance shall also be supplied for each consignment of GGBS or on weekly basis, whichever is more frequent.

(c) The early compressive strength of each consignment of GGBS shall be determined in accordance with BS EN 197 and BS EN 15167 or ASTM C989 at the independent site laboratory based on a blend of 50/50 % GGBS and CEM 1. Deviation of more than 5% in strength from either the previous consignment value or the rolling average shall be immediately reported to the Engineer. Testing at an independent laboratory shall be in accordance with per BS EN 197 and BS EN 15167 standards, and approved by the Engineer.

5 FA:

(a) Recent independent test results acceptable to the Engineer confirming compliance with specified requirements of BS EN 450 or ASTM C618.

(b) Manufacturer's certificates with all information necessary to verify compliance with internationally recognized standards shall also be supplied with each consignment of FA.

(c) The materials shall comply with QCS part 3. Deviation of the strength factor by more than 5% from either the previous consignment value or the rolling average shall be immediately reported to the Engineer and the Technical Manager of the premix company.

6 Silica fume:

(a) Recent independent test results acceptable to the Engineer confirming compliance with specified requirements and referenced standards.

(b) Manufacturer's certificates with all information necessary to verify compliance with internationally recognized standards shall also be supplied with each consignment of silica fume.

(c) 7 day pozzolanic activity test in accordance with BS EN 13263-1 or ASTM C 1240 on each consignment of silica fume at the Independent site laboratory. Deviation of the activity index by more than 5% from either the previous consignment value or the rolling average shall be immediately reported to the Engineer and the Technical Manager of the premix company.

7 Aggregates:


(b) Full details of the proposed sources of aggregates.

8 Water: Recent independent test results acceptable to the Engineer confirming compliance with the specified requirements and referenced standards.

QCS


9 Admixtures: Manufacturer’s technical specifications and recommendations. Recent trial results acceptable to the Engineer illustrating the efficiency of the product for its particular application. Tests on specific gravity and solids content shall be conducted at the Independent site laboratory on each consignment.

10 Mix Designs: Submit concrete mix designs for each type and strength of concrete required at least thirty (30) days before placing concrete.

11 New mix designs, with historic data less than 6 months, shall be verified by an approved independent testing laboratory in accordance with requirements of QCS Part 05 and shall be coordinated with design requirements and Contract Documents.

12 Submit complete mix design data for each separate mix to be used on the Project in a single submittal with at least the following information:

(a) Type of cement*.

(b) Portland cement content*.

(c) Cementitious content* (GGBS, FA, natural pozzolan, rice husk ash and/or silica fume).

(d) Max. aggregate size*.

(e) Combined grading curve for coarse aggregate

(f) Quantities of all individual materials*

(g) Type of admixture(s)*

(h) Target slump/slump flow (at discharge)* as per BS EN 12350-2

(i) Initial and final concrete setting time for each mix design as per ASTM C403 or equivalent BS EN standards, if specified

(j) Fresh density of concrete as per BS EN 12350-6

(k) Air content as per BS EN 12350-7

(l) Target temperature*

(m) Bleeding, if specified

(n) Chloride and sulphate (SO3) contents

(o) Details of calculated water/cementitious material (w/c) ratio*

(p) Compressive strength grade*

(q) Hardened density

(r) Water absorption (%) and water penetration (mm), if specified

(s) Rapid chloride permeability - Coulomb value, if specified

(t) Chloride migration coefficient (m2/sec), if specified

*Include on delivery ticket as a minimum

13 Data shall be from the same production facility that will be used for the Project.

14 Mix Design data shall include but not be limited to the following:

(a) Locations on the Project where each mix design is to be used corresponding to Structural General Notes on the Drawings.

(b) Proportions: Concrete constituent materials shall be proportioned to yield 1 m3

(c) Submit strength test records, mix design materials, conditions, and proportions for concrete used for record of tests, standard deviation calculation, and determination of required average compressive strength, if required by the Engineer.

QCS


(d) If early concrete strength is required, contractor shall submit trial mixture results as required.

(e) Test records to support proposed mixtures shall be no more than 12 months old and use current cement and aggregate sources. Test records to establish standard deviation may be older if necessary to have the required number of samples.

(f) Manufacturer's product data for each type of admixture.

(g) Manufacturer’s certifications that all admixtures used are compatible with each other.

(h) All information indicating compliance with Contract Documents including method of placement and method of curing.

15 Mass Concrete:

(a) Submit mix design for mass concrete elements in conformance with requirements of ACI 301 Section 8. The concrete mix design shall not be designed with a high early strength unless otherwise demonstrated by the Contractor for capability of maintaining proper temperature and approved by the Engineer.

(b) Submit proposed methods of temperature control, including cementitious material content control in mix design to reduce heat-generating potential of concrete, precooling of ingredients to lower concrete temperature as placed, and methods to protect mass concrete elements from excessive temperature differentials.

(c) Submit analysis of anticipated thermal development within mass concrete elements with the proposed mix design for these elements. Results of the analysis, using methods in ACI 207.1R and ACI 207.2R such as the Schmidt model and site specific data, shall address the maximum differential temperature and the maximum temperature during curing

(d) Submit proposed number and locations of temperature monitoring devices to record temperature development between the interior and the exterior of mass concrete elements.

6.2 EXPOSURE CLASSES

6.2.1 General

1 The exposure classes are related to the environmental conditions surrounding the concrete in service.

2 The concrete may be subject to more than one of the classes described below, and the environmental conditions to which it is subjected need to be expressed as a combination of exposure classes.

3 Where two or more aggressive characteristics lead to the same class, the exposure shall be classified into the next higher class; unless a special study for this specific case proves that it is not necessary.

4 For a given structure, different concrete elements may be subject to different environmental classes.

6.2.2 Reinforcement corrosion and sulphate classes

1 The classification system described below is based on the approach in BS EN 206-1, BS

8500-1, and the Concrete Society CS 163.

2 The exposure classes related to reinforcement corrosion are associated with carbonation and

chlorides as per Table 6.1.

QCS


3 The exposure classes related to sulphate attack are given in Table 6.2 in relation to sulphate

and pH of the ground water.

4 The sulphate content as S04 mg/l shall be determined as per BS EN 196-2.

5 The pH shall be determined as per ISO 4316.

Table 6.1.

Exposure classes for reinforcement corrosion

Exposure Class Class description

X0 No risk of corrosion or attack. Non saline conditions. Blinding concrete, non-reinforced concrete or slab on ground

X1 Mild exposure – Non saline conditions (dry or wet, rarely dry). External concrete at least 3m above ground level, internal concrete in dry conditions, concrete permanently submerged in non-saline water or non-aggressive groundwater (Class S1).

X2 Moderate exposure – Non saline conditions (cyclic wet and dry). External reinforced concrete less than 3m above ground level, water-retaining structures exposed to fluctuating water levels.

X3 Aggressive exposure – Permanently submerged or wet (rarely dry). Concrete in contact with groundwater including capillary rise zone, concrete containing or permanently exposed to saline water.

X4 Severe exposure – Moderate humidity. External concrete within 1km from the sea or in contact with high saline water table or sabkhas. Concrete not affected by condensation, irrigation or leakage, which are more than 3m above ground level.

X5 Extreme exposure – Cyclic wet and dry. External concrete within 1km from the sea or in contact with high saline groundwater or sabkhas. Concrete affected by condensation, irrigation or leakage, which are less than 3m above ground level or within capillary zone. Concrete surfaces exposed to sea water splash or in sea water tidal zone.

Table 6.2.

Sulphate exposure classes

Exposure class

Sulphate and magnesium Natural soil Brownfield1

2:1 water/soil or groundwater Static

water pH Mobile

water2 pH

Static water

pH

Mobile water

2 pH

SO4 (mg/l) Mg (mg/l)

S1 < 1500 > 3.5 Not mobile > 5.5 Not mobile

S2 1500-3000 > 3.5 Not mobile > 5.5 Not mobile

S3 3001-6000 ≤ 1000 > 3.5 Not mobile > 5.5 Not mobile

S4 > 6000 ≤ 1000 > 3.5 > 5.5 > 5.5 > 6.5

S5 > 6000 > 1000 > 3.5 > 5.5 > 5.5 > 6.5

Notes

1. Brownfield sites are those previously occupied and contain chemical residues into the ground or groundwater

2. The mobility of water shall be determined as described in the Concrete Society CS 163.

QCS


6.3 FRESH CONCRETE

6.3.1 General

1 Where adequate workability is difficult to obtain at the maximum water/cementitious ratio

allowed, the use of plasticisers or water reducing admixtures may be considered.

Alternatively an increase in cementitious content may be considered where this will not

adversely affect the durability of the concrete.

2 Cementitious contents in excess of 400 kg/m3 shall not be used unless special consideration

has been given to the effect for heat of hydration and reduce thermal stress in the concrete,

and approval has been obtained from the Engineer. The maximum cementitious content shall

not exceed 500kg/m³

3 The proportioning, mixing and placing of the mixture shall be in accordance with Parts 7 and

8 of this Section

4 Temperature (at placement):

(a) Maximum fresh concrete temperature shall not exceed 32°C unless construction

testing to verify a proposed concrete mixture will function satisfactorily at a concrete

temperature greater than 32°C. No concrete shall be placed if the concrete

temperature is above 35°C

(b) For mass concrete, the concrete producer shall demonstrate that temperature of

concrete due to hydration shall comply with the maximum fresh concrete temperature

specified. The supplier may use in his demonstration testing heat sensors and

simulation technologies which measure the concrete heat of hydration and its rate

versus concrete curing age.

5 The Contractor is responsible for ensuring that the concrete is able to be fully compacted

within the concrete element regardless of reinforcing density or other limitations. This may

involve reducing the maximum aggregate size, increase the level of concrete workability or

use self-compacting concrete.

6 Where the consistence of concrete is to be determined, it shall be measured either by means of:

(a) Slump test conforming to BS EN 12350-2

(b) Flow table test conforming to BS EN 12350-5

7 The consistence of concrete shall be determined at the time of use of the concrete or in the

case of ready-mix concrete, at the time of delivery.

8 The tolerances for the different consistence tests and target values are given in Table 6.3.

Table 6.3.

Tolerances for target values of consistence

Slump* Target value (mm) ≤ 40 50 to 90 ≥ 100

Tolerance (mm) -30, +40 -40, +50 -50, +60

Flow diameter* Target value (mm) All values

Tolerance (mm) -60, +70

* For spot samples taken from initial discharge.

QCS


6.4 GRADES OF CONCRETE

1 Where strength is classified with respect to compressive strength, Table 6.4 gives the

concrete grade with the requirements for w/c ratio and cementitious content.

2 The characteristic compressive strength at 28 days of 150mm cubes (fck, cube) or 150mm

diameter by 300mm cylinders (fck, cyl) may be used for the classification.

3 Exception will be made for concrete mixtures containing fly ash, silica fume or GGBS, where

testing shall be requested at 56 days, or 90 days as approved by the Engineer.

Table 6.4: Concrete grades and composition requirements

6.5 DURABILITY REQUIREMENTS

6.5.1 General

1 Constituent materials shall not contain harmful ingredients in such quantities as may be

detrimental to the durability of concrete or cause corrosion of the reinforcement.

2 For reinforced concrete in the ground, the need for protection from chlorides must be

balanced against the need for protection from sulphates.

3 Protective measures include the use of surface treatment, alternative reinforcement and

increasing the concrete cover. In every case, the need for good quality concrete with low

permeability is paramount.

Con

cre

te G

rad

e

Minimum characteristic cube strength (fck, cube)

Minimum characteristic

cylinder strength (fck, cyl)

Minimum cementitious content

Maximum Water : Cementitious

Ratio

(N/mm2) (N/mm

2) (kg/m

3) (w/c)

B 15 15 12 - -

B 20 20 16 - -

C 25 25 20 260 0.60

C 30 30 25 300 0.58

C 35 35 28 320 0.55

C 40 40 32 335 0.50

C45 45 35 355 0.47

C 50 50 40 370 0.45

C 60 60 50 380 0.40

C 75 75 60 390 0.35

QCS


6.5.2 Maximum acid soluble chloride content

1 The chloride content of the concrete, expressed as the percentage of chloride ions by mass

of cementitious materials, shall not exceed the values given in Table 6.5.

2 Calcium chloride and chloride based admixtures shall not be used in concrete containing

steel reinforcement or other embedded metal.

3 The determination of the chloride content in the concrete shall be conducted by the sum of

the contributions from the constituent materials as described in BS EN 206-1 and BS 8500-2.

Table 6.5.

Maximum chloride content of concrete (by weight of cementitious materials)

Concrete type Concrete made with sulphate

resisting Portland cement Concrete made with other cementitious

materials than SRPC

Reinforced concrete 0.15 % 0.3 %

Pre-stressed concrete 0.08 % 0.10 %

6.5.3 Type of cementitious material

1 Different types of cementitious materials offer different resistance to sulphate attack and

penetration of chlorides

2 The minimum cementitious content for different concrete grades is given in Table 6.4.

3 Table 6.6 gives the different types of cementitious materials and their combinations.

Table 6.6.

Cementitious materials and combinations

Cementitious material Percentage of components BS EN 197-1 designation

ASTM standard

Portland cement 100% PC CEM I Type 1

Sulphate-resistance Portland cement

100% SRPC - Type 5

PC/fly ash 65-79% PC

35-21% FA CEM II/B-V

PC/ground granulated blastfurnace slag

35-65% PC

65-35% GGBS CEM III/A

Triple blend

PC/FA/SF

55-70% PC

35-25% FA

10-5% SF

Triple blend PC/GGBS/SF

30-45% PC

60-50% GGBS

10-5% SF

QCS


6.5.4 Resistance to alkali-silica reaction

1 Alkali-silica reaction is the most common form of alkali-aggregate reaction.

2 Dry concrete is not prone to cracking by alkali-silica reaction, as it needs an external source

of water to develop sufficiently to cause cracking.

3 Where aggregate contain varieties of silica susceptible to attack by alkalis from cement and

other sources and the concrete is exposed to humid conditions, actions shall be taken to

prevent deleterious alkali-silica reaction using recommendations and procedures given in BS

EN 206-1 and BS 8500-2.

6.5.5 Recommendations to resist reinforcement corrosion

1 Durability design should start at the concept design stage, continuing through the design,

detailing, specification and execution phases.

2 This section covers the concrete grade, cementitious type, and minimum concrete cover for

various exposure classes as given in Table 6.1.

3 Table 6.7 provided recommended values of concrete grade and cover thickness to resist

reinforcement corrosion at different exposure classes.

Table 6.7.

Recommended durability requirement to resist reinforcement corrosion

*High level of cement replacement is required for severe and extreme exposure conditions.

Other protection measures such as coated reinforcement or surface treatment may be considered.

Exposure Class Minimum concrete cover (mm) Cementitious type

(Table 6.6)

X0 No risk of corrosion

25 All

X1 Mild 45 40 35 30 All

X2 Moderate - 50 45 40 35 All

X3 Aggressive - 70 65 60 55

PC/FA

PC/GGBS

Triple blend

X4 Severe* - 75 70 65 60

PC/FA

PC/GGBS

Triple blend

X5 Extreme* - 80 75 70 65 Triple blend

Minimum concrete grade

C30 C40 C50 C60 C75

QCS


6.5.6 Recommendations to resist sulphate attack

1 The exposure classification shall be identified based on the sulphate and magnesium

contents in the ground and groundwater, pH and mobility of groundwater as given in Table

6.2.

2 The recommended concrete specification requirements in terms of concrete grade and

cementitious type are given in Table 6.8.

3 Unless stated otherwise by the Engineer or project designs, all concrete below ground shall

have surface protection to prevent the movement of moisture from the ground, through the

foundations into the superstructure. The method of protection shall be in accordance with

Section 15 of the QCS or as approved by Qatar Standards.

Table 6.8

Recommended durability requirement to resist sulphate attack

Exposure class Minimum concrete grade Cementitious type

S1 C35 All

S2 C40

C50

Triple blend

SRPC, PC/FA, PC/GGBS

S3 C50

C60

Triple blend

SRPC, PC/FA, PC/GGBS

S4 C60

C75 Triple blend

S51 See Note See Note

Note: S5

1 requires special treatment when the sulphate content exceeds 6000 mg/l and the magnesium

content exceeds 1000 mg/l.

6.5.7 Durability-Related Properties

1 The durability of concrete is greatly influenced by the ability of the concrete cover to resist the

movement of liquid and gas through concrete.

2 The commonly used test for assessing the transport properties of concrete are listed in Table

6.9 together with typical values. Lower value indicates more durable concrete.

3 No values are currently specified for various exposure classes, but may be requested by the

Engineer. Table 6.9 gives the recommended durability-related properties and typical values

for the development of mix design and comparative performance as given in the Concrete

Society CS163.

4 For Severe and Extreme exposures, it is recommended to use high durable concrete (Table

6.9)

QCS


Table 6.9

Recommended properties and typical values for concrete

Concrete property Test method Age range between 28 and 90 days

High durability Minimum durability

Water absorption BS 1881: Part 122 2% 4%

Water penetration, BS EN 12390-8 5 mm 30 mm

Rapid chloride permeability (RCP), ASTM C 1202 500 coulombs 4000 coulombs

Chloride migration NT Build 492 2.0 x10-12

(m2/s) 9.0 x10

-12 (m

2/s)

1. Concrete shall be tested for any of the transport properties when requested by the Engineer and shall be tested at 28 days.

2. Exception will be made for concrete mixtures containing fly ash, silica fume or GGBS, where testing shall be requested at 56 days, or 90 days.

6.6 DESIGN OF CONCRETE MIXES

1 At the start of the construction period, the Contractor shall design a mix for each grade of

concrete as stated hereafter.

2 Each mix design shall be such that:

(a) the aggregate shall comprise fine aggregate and coarse aggregate with size specified in Section 5, Part 2.

(b) the combined aggregate grading shall be continuous

(c) the aggregate quantity shall be calculated by weight.

3 Where a concrete production facility has strength test records not more than 12 months old,

a sample standard deviation, Ss, shall be established. Test records from which Ss is

calculated shall consist of at least 30 consecutive tests or two groups of consecutive tests

totalling at least 30 tests

4 Where a concrete production facility does not have strength test records meeting

requirements of 6.6 (3) above, but does have test records not more than 12 months old

based on 15 to 29 consecutive tests, a sample standard deviation Ss shall be established as

the product of the calculated sample standard deviation and modification factor of Table 6.10

Table 6.10

Modification Factor for Sample Standard Deviation When Less Than 30 Tests Are Available

No. of tests Modification factor for sample standard

deviation

Less than 15 Use para 7. Below

15 1.16

20 1.08

25 1.03

30 1.00

1- Interpolate for intermediate number of tests

2- Modified sample standard deviation, Ss, to be used to determined required average strength f’cr

QCS


5 To determine the correction factor between cube strength and cylinder strength, the

contractor shall establish at least 30 consecutive strength tests from each proposed mix

design. This correction will remain valid thru the project providing that no change in the

properties of the materials and no change in source occurred.

6 Required average compressive strength (Target Mean Strength) f’cr used as the basis for

selection of concrete proportions shall be determined from Table 6.11 using the sample

standard deviation, Ss

Table 6.11:

Required Target Mean Strength when data are available

to establish a sample Standard Deviation

Specified compressive strength, N/mm2 or MPa

Required average compressive strength, Target Mean Strength, N/mm

2 or MPa

F’c < 35 MPa --- see footnote F’cr = f’c + 1.34Ss ------------------ Eq. 1

F’cr = f’c + 2.33Ss – 3.5 ---------- Eq. 2

F’c > 35 MPa --- see footnote F’cr = f’c + 1.34Ss ------------------ Eq. 1

F’cr = 0.90f’c + 2.33Ss ------------ Eq. 3

Note: Use the larger value computed from any equation

7 When a concrete production facility does not have field strength test records for calculation of

Ss, Required average strength (Target Mean Strength) f’cr shall be determined as follow:

(a) F’cr = f’c + 8.5 MPa when 20 < f’c < 35 MPa

(b) F’cr = 1.10f’c + 5 MPa when f’c > 35 MPa

6.6.1 Concrete

1 Portland cement concrete shall consist of a mixture of cementitious materials, fine aggregate,

coarse aggregate, water, and additives (when required). It shall be classified as in Table 6.4

unless otherwise stated hereafter and requested by the Engineer.

2 Blinding concrete

(a) Blinding concrete shall be of minimum Grade C15 and above.

(b) The thickness of the blinding concrete shall be as shown on the Drawings, but shall in

no instance be less than 75 mm.

(c) The surface finish to blinding concrete shall be Class U4 as specified in Clause 9.3.1

of Part 9 of this Section or as directed by the Engineer.

QCS


3 Mass Concrete

(a) The fresh concrete temperature at placing shall not exceed 21°C to minimise thermal

cracking. A higher temperature of up to 27°C may be accepted with a demonstration of

the satisfactory performance of concrete including mock up and thermal calculations.

The maximum allowable differential temperature between the interior and the exterior

of the mass concrete element shall not exceed 20 ° C. The maximum temperature in

any location within the mass concrete structure during curing shall not exceed 70 °C.

The drop in concrete surface temperature during, and at the conclusion of the

specified curing period, shall not exceed 11 °C in any 24 hour period.

4 Self-Compacting Concrete

(a) General: Self-Compacting Concrete (SCC) is a special concrete that requires

minimum or no vibration for placing and compaction. It is able to flow under its own

weight, completely filling formwork and achieving full compaction, even in the presence

of congested reinforcement. The hardened concrete is dense, homogeneous and has

the same engineering properties and durability as traditional vibrated, fully compacted

concrete.

(b) Self-Compacting Concrete Supplier: SCC shall be supplied by a competent concrete

producer with a record of successfully producing this type of concrete at considerable

volume and with high consistency.

(c) Constituent Materials, General: The constituent materials for SCC are the same as

those used in traditional concrete conforming to EN 206-1, as specified in part 2 of this

section.

(d) To achieve these requirements the control of the constituent materials needs to be

increased and the tolerable variations restricted, so that daily production of SCC is

within the conformity criteria without the need to test and/or adjust every batch.

(e) Recommended Test Requirements for SCC:

Laboratory tests Field Tests

Slump-flow 600 – 750 mm 550 – 750 mm

V-Funnel 6 – 25 sec N.A

L-Box (3 bars) > 0.80 N.A

J-Ring < 10mm N.A

(f) Concrete specimens shall be moulded in single layer without rodding and tapping

(g) Slump flow and VSI testing shall be performed as outlined in the European Guidelines

for SCC, BS EN 12350-8 and BS EN 12350-9 or ACI 237R 07 and ASTM C 1611/C

1611M

5 Pile Concrete

(a) The cementitious content shall not be less than 380 kg/m3, as specified in Section 4.

(b) The water-cementitious ratio shall not exceed 0.45

QCS


(c) The concrete mixture shall be designed of high slump not less than 150 mm allowing

proper free fall with excellent homogeneity. When concrete mixture requires slump of

greater than 230 mm, it shall be designed as Self-Compacting Concrete or as

instructed by the Engineer.

(d) The concrete slump shall have adequate workability retention using approved type of

retarder and shall be submitted in the design mix.

(e) The increase in workability shall not permit any decrease in the specified design

strength

(f) The concrete in a pile shall, if at all possible, be placed in one continuous operation.

6 Underwater Concrete

(a) Shall comply with ACI 304 Chapter 8

(b) The Cementitious content shall not be less than 390 kg/m3

(c) The water-cementitious ratio must not exceed 0.40

(d) Fine aggregate contents of 45 to 55% by volume of total aggregate and air contents of

up to approximately 5% are generally specified.

(e) Concrete shall be more cohesive and less prone to washout of cement or fines from

the concrete during placement. Antiwashout admixtures or alternative concrete mix

shall be used for underwater concrete.

(f) Trial placements shall be conducted to verify that the concrete proportioned with the

antiwashout admixture can maintain adequate slump life and can flow for the required

distance.

(g) The concrete mixture shall be designed of high slump not less than 150 mm allowing

proper free fall with excellent homogeneity. The use of air-entraining admixture shall

be evaluated as it increases the workability. When concrete mixture requires slump of

greater than 230 mm, it shall be designed as Self Compacted Concrete. The increase

in slump shall be made using proper admixtures.

(h) The concrete slump shall have adequate retention using approved type of retarder and

shall be submitted in the design mix.

(i) The increase in workability shall not permit any decrease in the specified design

strength

(j) The concrete shall be placed in one continuous operation

(k) The final selection of a concrete mixture shall be based on test placements made

under water in a placement box or in a pit that can be dewatered after the placement.

Test placements shall be examined for concrete surface flatness, amount of laitance

present, quality of concrete at the extreme flow distance of the test, and flow around

embedded items, if appropriate.

7 Shotcrete

(a) The classification of shotcreting shall be in accordance to the process used (wet-mix

or dry-mix) and the size of aggregates used.

(b) All materials shall be as per QCS except for aggregate where gradation shall be as per

ACI 506R and 506.2R

QCS


(c) Steel and synthetic fibers will be used to reduce propagation of cracks. Fibers shall be

as per Manufacturer supplier data sheet and shall conform to ASTM A 820 for steel

fibers and ASTM C1116 for synthetic fibers.

(d) The nozzle operator should be certified (refer to ACI CP-60) and have completed at

least one similar application as a nozzle operator on a similar project. The nozzle

operator should also be able to demonstrate, by test, an ability to satisfactorily perform

the required duties and to apply shotcrete as required by specifications

(e) Before shotcreting the surface shall be prepared and maintained before and during

shotcrete application. Surface preparation shall conform to ACI 506 R chap. 5

(f) The cementitious content shall not be less than 360 kg/m3 where wet-mix is applied

the slump shall be in the range of 40 to 80 mm

(g) Normal testing ages for compressive strength are 7 and 28 days; however, shorter

periods may be required for particular applications or conditions as directed by the

Engineer. Testing shall be on daily production or every 30 m3 whichever is greater.

(h) Sampling and testing, however, should be varied according to the size and complexity

of the project. Sampling should be done in accordance with ASTM C 1385. Making

extra cylinders or panels shall be at the request of Engineer if testing results vary.

(i) Testing for water absorption and drying shrinkage shall be at the request of the

Engineer.

(j) Fiber-reinforced shotcrete requires fiber washout tests or flexural toughness testing

according to ASTM C 1018.

(k) Acceptance of shotcrete should be based on results obtained from drilled cores or

sawed cubes (ASTM C 42). The use of data from nondestructive testing devices, such

as impact hammers or probes (ASTM C 805, ASTM C 803), ultrasonic equipment

(ASTM C 597), and pull-out devices (ASTM C 900) may be useful in determining the

uniformity and quality of the in-place shotcrete. These tests, however, may not provide

reliable values for compressive strength.

(l) Core grading is a method used to evaluate encasement of reinforcement. Core

grading shall be used for nozzle operator evaluation. Core grading should not be used

to evaluate structures.

8 No-Fines Concrete and Pervious concrete

(a) No-fines concrete shall be made using a coarse aggregate conforming QCS section 5

part 3

(b) Proportion of aggregate, cement and water shall be determined by trial mixes by the

Contractor and to be accepted by the Engineer.

(c) All the aggregate particles are to be coated with a film of cement grout.

(d) No-fines concrete when placed shall contain no layers of laitance.

(e) No-fines concrete shall not be mixed by hand.

(f) Mechanical vibration shall not be used to compact no-fines concrete.

(g) Three test cubes of no-fines concrete shall be made of each preliminary mix.

(h) Minimum crushing strength of the chosen mix shall be 5 MPa at 28 days.

QCS


(i) The porosity of no-fines concrete shall be such that water will pass through a slab

300 mm thick at the rate of not less than 7 l/m2 • s of slab with a constant 100 mm

depth of water on the slab.

(j) Where a slab incorporating vertical weep holes or drain holes is casted above a layer

of no-fines concrete; any polyethylene sheeting shall be pierced below the pipes

forming such drain holes and the edges of the sheeting sealed to the lower end of the

pipe to prevent the ingress of grout and fine particles from the slab concrete into the

no-fines concrete.

(k) The limit for the maximum height of drop while placing is not applicable for no fines

concrete.

(l) Formwork shall remain in place until the no fines concrete has gained adequate

strength to support itself as per the requirements of Part 10 of this Section.

(m) Curing shall be carried out in accordance with the provisions of Part 11 of this Section

(n) The fresh density of Pervious concrete shall be tested as per ASTM C1688 and the

infiltration rate shall be tested as per ASTM C1701 and to follow ACI 522.1R for testing

and quality control scheme.

9 Concrete with recycled aggregates shall be generally approved once the source of recycled

aggregates is identified based on type and approved by the Engineer.

(a) The recycled aggregates shall meet with BS EN 12620 and QCS requirements.

(b) The concrete made with recycled aggregates shall be limited to design strength of C40

MPa cube strength; unless otherwise accepted by the Engineer. BS EN 206-1 shall be

the code of practice and guide for the usage of recycled concrete aggregates in

concrete or ACI 555 and BRE digest 433.

(c) The Water-cementitious ratio shall not exceed 0.50

(d) To determine a target mean strength on the basis of a required strength, a higher

standard deviation (increased by 40%) shall be used when designing a concrete with

recycled aggregates of variable quality than when recycled aggregate of uniform

quality or virgin aggregates are used

(e) Specific gravity, unit weight, and absorption of aggregates should be determined

before mixture proportion studies

(f) The mixture proportion should be based on the measured density of the recycled

aggregates intended in the job concrete

(g) Trial mixes shall be made to verify the requirements with project specification and

QCS.

10 Heavyweight and radiation shielding concrete

(a) The quality of the aggregates should comply with the requirements of QCS for normal

weight aggregates, ASTM C 637 for heavyweight aggregates and ASTM C638 for

aggregates to be used in radiation-shielding concrete.

(b) When ferrophosphorous aggregates are used, tests shall be made to determine if

gases (nontoxic) might be released during construction.

(c) Aggregates shall be checked for every delivery to ensure that they conform completely

with purchase specifications

QCS


(d) Aggregates shall be frequently evaluated for the effects of deleterious substances or

aggregate coatings on concrete strength or the promotion of corrosion in metallic

aggregates or embedment’s

(e) The chemical properties of all high-density aggregates must be provided to the

Engineer for evaluation before use with due consideration given to chemical reactivity,

particularly in highly alkaline environment as found in cement paste.

(f) Tests for alkali-aggregate reactivity shall be determined from each source and supplier

and shall be made every 3 months.

(g) The fresh density of high-density concrete shall be made from each truck

(h) Lead shot concrete shall not be use for structural concrete.

(i) Thermal conductivity, elastic behaviour and shrinkage, hardened density, strength as

well as other hardened concrete properties shall be tested and verified before the use

of concrete.

11 Fiber-Reinforced Concrete

(a) Classification of fiber-reinforced concrete shall be made based on the material type of

the fiber incorporated:

(i) Type I Steel Fiber-Reinforced Concrete—Contains stainless steel, alloy steel, or

carbon steel fibers conforming to Specification of BS EN 14889-1 or ASTM

A820 /A820M .

(ii) Type II Glass Fiber-Reinforced Concrete—Contains alkali-resistant (AR) glass

fibers conforming to Specification C 1666/C 1666M.

(iii) Type III Synthetic Fiber-Reinforced Concrete— Contains synthetic fibers for

which documentary evidence can be produced confirming their long-term

resistance to deterioration when in contact with the moisture and alkalis present

in cement paste and the substances present in admixtures and shall conform to

BS EN 14889-2

(iv) Type IV Natural Fiber-Reinforced Concrete— Contains natural fibers for which

documentary evidence can be produced confirming their long-term resistance to

deterioration when in contact with the moisture and alkalis present in cement

paste and the substances present in admixtures. Test Method ASTM D 6942

shall be used to determine the susceptibility of these fibers to deterioration as a

result of exposure to alkalis in concrete

(v) When the purchaser chooses to permit the use of fibers other than those

complying with the above classifications, the manufacturer or supplier shall

show evidence satisfactory to the purchaser that the type of fiber proposed for

use shows long-term resistance to deterioration when in contact with the

moisture and alkalis present in cement paste and the substances present in

admixtures

(b) The contractor shall submit:

(i) Type of fiber-reinforced concrete required

(ii) Designated size, or sizes, of coarse aggregates

QCS


(c) Slump or time of flow required at the point of delivery, or when appropriate the point of

placement, subject to the tolerances hereinafter specified Slump shall be specified

when it is anticipated to be 50 mm or more. Except as otherwise specifically permitted

by the Engineer, cement, supplementary cementitious materials, fine and coarse

aggregates, mixing water, and admixtures shall be measured in accordance with the

applicable requirements of QCS

(d) Fibers shall be measured by mass. When the fibers are to be measured by mass,

bags, boxes, or like containers are acceptable provided that such like containers are

sealed by the fiber manufacturer and have the mass contained therein clearly marked.

No fraction of a container delivered unsealed, or left over from previous work, shall be

used unless weighed.

(e) Prepackaged, dry, combined materials, including fibers, shall comply with the

packaging and marking requirements of Specification ASTM C 387 or C 1480 and

shall be accepted for use provided that after addition of water, the resulting fiber

reinforced concrete meets the performance requirements of this specification

(f) Batching plant used for the preparation of continuously mixed fiber-reinforced concrete

shall comply with the applicable requirements of NRMCA. Fiber-reinforced concrete

shall be added directly to the concrete at the time of batching in amounts in accord

with approved submittals for each type of concrete required. Mix concrete in strict

accord with fiber-reinforced concrete manufacturer, instructions and recommendations

(g) Fiber-reinforced concrete shall be free of fiber balls when delivered

(h) The manufacturer of the fiber-reinforced concrete shall furnish to the purchaser a

delivery ticket or statement of particulars on which is printed, stamped, or written,

information with details of the type, brand, and amount of fibers used.

(i) The contractor shall afford the inspector all reasonable access, without charge, for the

procurement of samples of freshly mixed fiber-reinforced concrete at the time of

placement to determine compliance with the requirements of this specification.

(j) Samples of batch-mixed fiber-reinforced concrete shall be obtained in accordance with

Practice ASTM C 172 or C 1385/C 1385M for shotcrete as appropriate, except that

wet-sieving shall not be permitted. Sampling for uniformity tests shall be in accordance

with specification ASTM C 94/C 94M

(k) If the measured slumps, time of flow, or air content fall outside the limits permitted by

this specification, make a check test immediately on another portion of the same

sample. If the results again fall outside the permitted limits, the material represented by

the sample fails to meet the requirements of this specification

(l) The following shall apply to all forms of fiber-reinforced concrete except dry-mix

shotcrete. When applicable, the slump shall be in tolerance with this section para

6.4.2.5 (a) and (b).

(m) The time of flow shall be in the tolerances as follow:

(i) When the project specifications for time of flow are written as a “minimum” or

“not less than” requirement

Specified time of flow

If 15sec or less If more than 15 sec

Plus Tolerance 5s 10s

Minus Tolerance 0s 0s

QCS


(ii) When the project specifications for time of flow are not written as a “minimum”

or “not less than” requirement:

Tolerances for time of flow

For specified time of flow Tolerance

8 to 15 s + 3s

More than 15 s + 5s

(n) Finishability - Pre-project trials shall be utilized to determine acceptable surface

finishability by the Engineer. The manufacturer shall provide the services of a qualified

technician to instruct the concrete supplier in proper batching and mixing of materials

to be provided.

(o) Provide fibers for concrete reinforcing capable of achieving a two hour fire resistance

rating when tested under ASTM E 119. Fire tests must be certified.

12 Lightweight concrete

(a) This clause of the specification refers to lightweight concrete with improved insulation properties where the practical range of densities is between about 300 and 1850 kg/m3.

(b) The required density and strength of the lightweight concrete will be specified on the drawings or directed by the Engineer.

(c) The method of production of lightweight concrete will be shown on the drawings or directed by the Engineer. The Contractor shall submit full technical details of the materials and method of production for the lightweight concrete along with a list of previous projects where the particular system has been used.

(d) After source approval of the material and system the Contractor shall submit a mix design for the lightweight concrete for the approval of the Engineer. After the review and approval of the mix theoretical mix design the Contractor shall carry out a trial mix to check the workability of the fresh concrete and to allow samples to be made for compressive strength and density.

(e) The Engineer may also instruct that tests are carried out for abrasion resistance and thermal insulation properties.

(f) Iightweight concrete shall be made with lightweight aggregates as approved in part 2 of section 05 in QCS for its use in concrete

(g) The performance of lightweight concrete shall follow ACI 213R

6.7 TRIAL MIXES

1 As soon as the Engineer has approved the concrete mix design for each grade of concrete and during or following the carrying out of the preliminary tests, the Contractor shall prepare a trial mix of each grade in the presence of the Engineer at least 35 days before commencement of concreting. Trial mix shall be mixed and handled by means of the same plant which the Contractor proposes to use in the Works. The trial mix shall comprise not less than 50% from the central mixing drum capacity but not less than 3.0 m

3 of concrete.

The trial mix can be exempted if concrete supplier provides through an independent approved testing agency adequate history on strength:

(a) Not less than 30 strength test results as in para 6.6 of this specification

(b) The results shall valid by no more than 6 months from the date of approval

2 Batch the field concrete trial mixture within -5°C of the proposed maximum allowable fresh concrete temperature in a truck-mixer with a minimum batch size of 3 m

3.

QCS


3 The concrete mixture shall be held in the mixer for 120 minutes, unless otherwise specified by the Engineer. During the entire 120-minute period, agitate the mixer at 1 to 6 rpm. At the end of 120 minutes, mix the concrete mixture at full mixing speed designated by the manufacturer (6 to 18 rpm) for 2 minutes.

4 For each trial mix, a plant production trial shall be carried out and the slump of the concrete checked immediately after discharge from the mixer and thereafter at 30 min intervals up to the maximum time period envisaged for delivery and standing on site. Based on this trial the mix design shall identify any adjustments to the range of plasticiser for acceptable workability for different times after batching. Where ready mix concrete is being used, the above requirement may be waived at the discretion of the Engineer if the Contractor has documented previous experience of a particular mix design with test results available.

5 The proportions of cement, aggregate and water shall be carefully determined by weight in accordance with the Contractor's approved mix design (or modified mix design after preliminary tests).

6 Each sample shall consist of at least 9 specimens for strength analysis where 3 specimens for each age will be tested to determine the concrete strength at the required age.

7 If either or both the average value of the strength of the three cubes tested at 28 d is less

than the required strength (target strength) or the difference between the greatest and the

least strengths is more than 15 % of the average strengths, as per BS EN 206-1, the

Contractor shall take measures as deemed necessary such as:

(a) Propose new mix design

(b) Provide new materials and prepare and test further trial mixes until specified requirements are achieved.

8 Additionally, the Contractor shall measure the temperature, workability of concrete in each batch.

9 When requested by engineer, a mock-up of 2x2x2 m3 shall be made at jobsite and full scale

tests of the workability of each trial mix shall be made by the Contractor in the presence of the Engineer. The following tests shall be made on the Site by filling trial moulds to confirm the suitability of:

(a) mix for the works

(b) type of plant used for mixing

(c) face intended for use in the works

(d) type of form oil

(e) type of protective coatings.

10 Redesign of the concrete mixes and trial mixes of concrete shall be repeated for each grade of concrete until the concrete meets the requirements in this specification and it is verified by full scale mockup test as described above.

11 Approval of the job-mix proportions by the Engineer or his assistance to the Contractor in establishing those proportions, in no way relieves the Contractor of the responsibility of producing concrete which meets the requirements of this Specification.

12 All costs connected with the preparations of trial mixes and the design of the job mixes shall be borne by the Contractor.

13 The Contractor shall declare any change in the source of the material and any changes in the cement content consumption greater than 20.0kg/m³ from that used in the trial mixes.

QCS



6.8.1 General

1 In order to ensure that the quality of materials and mix proportions are maintained throughout concreting operations, sampling and testing shall be carried out using the relevant standard procedures and all other relevant codes quoted in this specification in accordance with a routine testing program that shall be agreed with the Engineer before the start of concrete work.

2 The Contractor, through a third party approved testing agency, shall supply all necessary tools for tests, shall cast all concrete specimens, strip and store them in water as stated in BS EN 12390-2. The Contractor shall also arrange for the transport of samples to the place of testing and shall supply the Engineer with duplicate copies of all test certificates.

6.8.2 Tests for Concrete

1 Unless the Engineer directs otherwise, the program shall include at least the tests specified below.

2 Tests on aggregates shall be as described in Part 2 of this Section.

3 Concrete shall be tested in accordance with the requirements of this specification by qualified field testing technicians or engineer. Concrete testing laboratory personnel shall be certified from a recognised Institution. Field personnel’s in charge of sampling concrete; testing for slump, and temperature; and making and curing test specimens shall be certified from a recognised Institution too.

4 Slump tests (and VSI testing when applicable) shall be carried out at the rate of one test per load of concrete delivered to the Site, or one test per 10 m

3 whichever is the lesser for the

first 50 m3 of concrete then at a rate of 1 slump test for every 50 m

3 if concrete was

consistent during production. In the event of inconsistent slump values, the Engineer may instruct the Contractor to check the slump test on each truck of concrete at the plant. The Contractor shall carry out an investigation to establish the cause of the high variation in slump and shall take any necessary corrective measures. The slump requirements for the fresh concrete are to be approved by the Engineer.

5 The adjustment for the slump of concrete to fit the job requirement can be conducted only one time using a proper additive at jobsite provided that such addition does not increase the water-cement ratio and setting time above the maximum permitted by the specifications. This addition will only be made at the approval of Engineer.

6 Concrete shall be available within the permissible range of slump for a period of 30 min starting either on arrival at the job site or after the initial slump adjustment as permitted above, whichever is later. The first and last quarter m

3 discharged are exempt from this

requirement. If the user is unprepared for discharge of the concrete from the vehicle, the producer shall not be responsible for the limitation of minimum slump after 30 min have elapsed starting either on arrival of the vehicle at the prescribed destination or at the requested delivery time, whichever is later.

7 When air-entrained concrete is desired the purchaser shall specify the total air content of the concrete. The air content of air-entrained concrete when sampled from the transportation unit at the point of discharge shall be within a tolerance of +1.5% of the specified value.

QCS


8 Concrete strength test:

(a) Each concrete strength sample shall consist of at least seven specimens, two to be tested at 7 days, three at 28 days and two to be tested at the discretion of the Engineer. Additional samples may be prepared as directed by the Engineer to be tested at the discretion of the Engineer for strength and/or durability.

(b) When concrete cylinders have been specified, the concrete specimens shall not be capped using sulphur for environmental effect. The Contractor shall follow one of the following procedures and as approved by the Engineer:

(i) Cap the specimens in accordance with ASTM C617 using neat cement paste and/or High-strength gypsum cement paste

(ii) Saw cut and Grind the surface of the concrete to the desired planeness and perpendicular

(iii) Test the concrete cylinders using Unbonded Caps in accordance with ASTM C1231

(iv) For field specimens, the contractor has the right to either use the conversion listed in EN 206 or determine the conversion factor for each specified concrete mix design by testing at least 36 comparative specimens (i.e. 18 cubes versus 18 cylinders sampled from 3 consecutive batch trial mix).

(c) A minimum of one sample shall be taken of each mix every day the mix is used

(d) Samples shall be taken at the average rate of the followings:

(i) One sample every 30 m3, if the pour is less than or equal to 90 m3

(ii) One sample every 100 m3, if the pour is greater than 90m3 and equal to or less

than 2000 m3,

(iii) One sample every 200 m3, if the pour exceeds 2000 m3.

(e) Test specimens for compressive strength testing shall be prepared and cured in

accordance with BS EN 12390-2. The compressive strength of the specimens shall be

determined in accordance with BS EN 12390-3.

(f) A test shall be the average of the strength of the specimens tested at the age

specified. If a specimen shows definite evidence other than low strength, of improper

sampling, moulding, handling, curing, or testing, it shall be discarded and the strength

of the remaining cubes shall then be considered the test result.

(g) Identity criteria of concrete strength shall be assessed for each individual test result

and the average of non-overlapping results as per BS EN 206-1 and explained below:

(i) The average strength tests (average of two specimens or more) shall be equal

to or greater than the characteristic (fck) + 2 MPa, and

(ii) Any individual test result shall be equal to or greater than fck – 4 MPa. The test

result shall be that obtained from the average of the results of two or more

specimens made from one sample for testing at the same age.

9 If works test specimens fail at 28 days the Contractor shall suspend concreting operations

and shall not proceed further without approval. The Contractor shall carry out in-situ testing

of the suspect concrete in accordance with Part 13 of this Section, in the presence of the

Engineer. All defective work shall be replaced and retested to the satisfaction of the

Engineer.

QCS


6.8.3 Hardened Tests for Fiber-Reinforced Concrete

(a) When post-crack flexural performance is used as the basis for acceptance of fiber-

reinforced concrete, make, condition, and test sets of test specimens in accordance

with Test Method ASTM C1399, C1550 or C1609/C1609M as specified.

(b) When flexural strength is used as the basis for acceptance, make and test sets of at

least three test specimens in accordance with the requirements for sampling and

conditioning given in Test Method ASTM C1609/C1609M. Test specimens

representing thin sections, as defined in C1609/C1609M, or specimens representing

fiber-reinforced shotcrete of any thickness, shall be tested as cast or placed without

being turned on their sides before placement on the support system. Acceptance shall

not be based on flexural strength alone when post-crack performance is important.

Test Method C1609/C1609M provides for the determination of first peak flexural

strength when required by the purchaser. For many type-amount fiber combinations,

the first peak flexural strength is not significantly greater than the peak strength in

flexure.

(c) When compressive strength is used as part of the basis for acceptance of fiber-

reinforced concrete, make sets of at least two test specimens in accordance with the

applicable requirements of Practices ASTM C31/C31M and C192/C192M and as

specified in this section, or Test Methods C42/C42M or C1604/C1604M and condition

and test in accordance with Test Methods BS EN 12390, C39/C39M, C42/ C42M, or

C1604/C1604M. Acceptance shall not be based on compressive strength alone.

(d) The frequency of tests on hardened fiber-reinforced concrete shall be in accordance

with the following requirements:

(i) Batch-Mixing: Tests shall be made with same frequency as in conventional

concrete. Each test shall be made from a separate batch. On each day fiber-

reinforced concrete is mixed, at least one test shall be made for each class of

material.

(ii) When fibers are added, subject for approval of the Engineer, at the truck mixer

the tests shall be made for each 20 m3 or fraction thereof, or whenever

significant changes have been made in the proportioning controls. On each day

fiber-reinforced concrete is mixed, at least one test shall be made for each class

of material.

(iii) For Shotcrete: Tests shall be made for each 38 m3 placed using specimens

sawed or cored from the structure or from corresponding test panels prepared in

accordance with Practice ASTM C1604 and C 1140. On each day fiber-

reinforced shotcrete is prepared; at least one test shall be made for each class

of material.

6.8.4 Quality Control charts

1 The Contractor shall submit a continuous statistical analysis, on a monthly basis, for strength

showing the potential strength of the concrete, variations in measured strength by

determining the standard deviation (margin), batch-to-batch variations of the proportions and

characteristics of the constituent materials in the concrete, the production, delivery, and

handling process, and climatic conditions; and variations in the sampling, specimen

preparation, curing, and testing procedures (within-test).

QCS


2 The Contractor shall provide in his analysis the mean strength, calculated standard deviation,

the normal distribution of concrete strength and the frequency histogram. The Contractor

shall draw the upper and lower lines for warning line (Target mean strength + 2 x standard

deviation) and control line (Target mean strength + 3 x standard deviation)

3 The contractor shall use the methods, of computing standard deviation along with coefficient

of variation and factors for computing within-test standard deviation from range, addressed in

ACI 214

4 This recalculated margin, if adopted by the Engineer, becomes the current margin for the

judgement of compliance with the specified characteristic strength of concrete

6.9 WORKS TEST CUBES

1 Test cubes shall be taken as specified from fresh mixed concrete which is being used in the

Works and which has been prepared in the normal way.

2 Cubes shall be numbered sequentially and marked:

(a) Time, date and name of individual

(b) Section of work from which samples are taken

(c) Mix reference and delivery note number

(d) Name of technician

(e) and any other relevant information.

3 Tests for slump, as per BS EN 12350-2, and temperature shall be made and recorded

whenever samples are taken.

4 The cube manufacture shall be in accordance with BS EN 12390-2.

5 When Self Compacting Concrete is used, the concrete specimens shall not be consolidated

in moulds and it shall be placed in a single lift then levelled with minimum manipulation.

6 All samples shall be moulded at jobsite on a levelled surface area to within 20 mm per meter

7 Immediately after moulding and finishing, the specimens shall be stored for a period up to 48

h in a temperature range from 20 to 26°C and in an environment preventing moisture loss

from the specimens

8 Specimens shall not be transported or handled until at least 14 h after casting

9 Transportation time from site to laboratory for final curing and strength testing shall not

exceed 4 hours. Specimens shall be protected from direct sun or rapid evaporation and

placed on cushion layer to reduce vibration

6.10 REJECTION OF CONCRETE MIXES

6.10.1 Rejection of Concrete Mixes:

1 Concrete mixes shall be rejected if they fail to meet one or more requirements, which cannot

be brought into compliance as related to any of the following:

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(a) Improper class or grade of concrete

(b) Slump or temperature not within specified limits

(c) Oversized aggregate

(d) Maximum water-cementitious ratio is exceeded

2 Concrete shall not be rejected unless it has been visually inspected by the Engineer or

representatives.

6.10.2 Unsatisfactory Concrete Works

1 A test shall be the average of the strengths of the specimens tested at the age specified. If a

specimen shows definite evidence other than low strength, of improper sampling, moulding,

handling, curing, or testing, it shall be discarded and the strength of the remaining specimens

shall then be considered the test result and where the range of the test values is more than

15 % of the mean, the results shall be disregarded unless an investigation reveals an

acceptable reason to justify disregarding an individual test value. To conform to the

requirements of this specification, strength tests representing each class of concrete must

meet the following requirements:

(a) The average of any three consecutive strength tests shall be equal to, or greater than,

the specified strength, f ‘c, and

(b) When the specified strength is 35 MPa or less, no individual strength test (average of

at least two specimen tests) shall be more than 3.5 MPa below the specified strength, f

‘c

(c) When the specified strength is greater than 35 MPa, no individual strength test

(average of two specimen tests) shall be less than 0.90 f ‘c.

2 Should any of the test results be unsatisfactory, the Engineer may order the work to be

stopped pending his further instructions. Executed work for which test results are

unsatisfactory shall be liable to rejection and if so advised the work shall be rebuilt at the

Contractor's expense.

3 In the case of the 7-day works cube tests proving unsatisfactory, the work may be stopped

liable to rejection pending the result of the 28-day test. If the test results fail to comply with

the requirements, the work represented shall be immediately liable to rejection.

4 The cost of all such cuttings, preparation of specimens, transportation and testing, and of

making good the portions of the structure affected shall be borne by the Contractor.

5 Regardless of satisfactory test cube results, any concrete work which, in the Engineer's

opinion, is excessively honeycombed or in any other way is defective, shall be liable to

rejection. Minor defects apparent on stripping the formwork must be made good at the

Contractor's expense. No such repair work shall be carried out until after inspection by the

Engineer and his acceptance of the proposed treatment has been given. Work which has

not been previously inspected but which shows signs of such treatment shall be liable to

rejection as defective work.

6 The cost of all delays on site due to faulty concrete work shall be met by the Contractor.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 07: Concrete Plants

7 CONCRETE PLANTS .............................................................................................. 2

7.1 GENERAL ............................................................................................................... 2

7.1.1 Scope 2

7.1.2 References 2

7.2 BATCHING .............................................................................................................. 3

7.2.1 General 3

7.2.2 Plant Type 5

7.2.3 Bins and Weight Batchers 5

7.2.4 Tolerances of Measuring Equipment 5

7.2.5 Batching Tolerances 6

7.2.6 Charging the Mixer 7

7.3 MIXING .................................................................................................................... 7

7.3.1 Charging Concrete Materials 7

7.3.2 Mixing Time for Stationary Mixers 7

7.3.3 Mixing 8

7.3.4 Limitation of Water : Cement Ratio 8

7.4 READY-MIXED CONCRETE ................................................................................... 9

7.4.1 General 9

7.5 APPENDIX A: CONCRETE PLANT INSPECTION – CHECKLIST ........................ 11

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7 CONCRETE PLANTS

7.1 GENERAL

7.1.1 Scope

1 This Part covers batching and mixing of concrete together with inspection of concrete plants.


This Section

Part 1 ............... General

Part 2 ............... Aggregates

Part 3 ............... Cementitious materials

Part 4 ............... Water

Part 5 ............... Admixtures


Part 8 ............... Transporting and Placing of Concrete

Part 15 ............. Hot Weather Concreting


7.1.2 References

ACI 304 ...................... Guides for Measuring, Mixing, Transporting, and Placing Concrete

ASTM C94 .................. Specification for ready-mixed concrete

BS 1881 ...................... Testing concrete

BS 8500 ...................... Concrete Specification complementary to EN 206

BS EN 12390 .............. Testing of hardened concrete

BS EN 12390-1:2000 . Testing hardened concrete — Part 1: Shape, dimensions and other

requirements for specimens and moulds

BS EN 12390-2:2000 . Testing hardened concrete — Part 2: Making and curing specimens

for strength tests

BS EN 12390-3:2000 . Testing hardened concrete — Part 3: Compressive strength of test

specimens

BS EN 12390-4:2000 . Testing hardened concrete — Part 4: Compressive strength -

Specification for testing machines

BS EN 12390-5:2000 . Testing hardened concrete — Part 5: Flexural strength of test

specimens

BS EN 12390-6:2000 . Testing hardened concrete — Part 6: Tensile splitting strength of test

specimens

BS EN 12390-7:2000 . Testing hardened concrete — Part 7: Density of hardened concrete

BS EN 12390-8:2000 . Testing hardened concrete — Part 8: Depth of penetration of water

under pressure

BS EN 12350 .............. Testing fresh concrete

BS EN 12350-1:2000 . Testing fresh concrete - Part 1: Sampling

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BS EN 12350-2:2000 . Testing fresh concrete - Part 2: Slump test

BS EN 12350-3:2000 . Testing fresh concrete - Part 3: Vebe test

BS EN 12350-4:2000 Testing fresh concrete - Part 4: Degree of compatibility

BS EN 12350-5:2000 Testing fresh concrete - Part 5: Flow table test

BS EN 12350-6:2000 Testing fresh concrete - Part 6: Density

BS EN 12350-7:2000 Testing fresh concrete - Part 7: Air content - Pressure methods

GSO EN 206-1, .......... Concrete. Specification, performance, production and conformity


GSO ISO 1920-2 ........ Testing of concrete – part 2: properties of fresh concrete

GSO ISO 1920-3 ........ Testing of concrete – part 3: Making and curing test specimens.

GSO ISO 1920-4 ........ Testing of concrete – part 4: strength of hardened concrete.

GSO ISO 1920-5 ........ Testing of concrete – part 5: properties hardened concrete other than

strength.


concrete core.

GSO ISO 1920-7 ........ Testing of concrete – part 7: Non–destructive test on hardened

concrete.

ISO 1920-8 ................. Testing of concrete -- Part 8: Determination of drying shrinkage of

concrete for samples prepared in the field or in the laboratory

ISO 1920-9 ................. Testing of concrete -- Part 9: Determination of creep of concrete

cylinders in compression

ISO 1920-10 ............... Testing of concrete -- Part 10: Determination of static modulus of

elasticity in compression

7.2 BATCHING

7.2.1 General

1 During measurement operations, aggregates shall be handled in a manner to maintain their

desired grading, and all materials shall be weighed to the tolerances required for the desired

reproducibility of the selected concrete mix.

2 The coarse aggregate shall be controlled to minimize segregation and undersized material.

Fine aggregate shall be controlled to minimize variations in gradation, giving special attention

to keeping finer fractions uniform and exercising care to avoid excessive removal of fines

during processing

3 Avoid blending two sizes of fine aggregate by placing alternate amounts in bins or stockpiles

or when loading cars or trucks. Satisfactory results are achieved when different size fractions

are blended as they flow into a stream from regulating gates or feeders. A more reliable

method of control for a wide range of plant and job conditions, however, is to separate

storage, handling, and batching of the coarse and fine fractions




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4 Stockpiling of coarse aggregate shall be kept to a minimum because fines tend to settle and

accumulate. When stockpiling is necessary use of correct methods minimizes problems with

fines, segregation, aggregate breakage, excessive variation in gradation, and contamination.

Stockpiles shall be built up in horizontal or gently sloping layers, not by end-dumping. Trucks,

loaders, and dozers, or other equipment shall not be operated on the stockpiles because, in

addition to breaking the aggregate, they frequently track dirt onto the piles

5 Stockpiles located to prevent contamination; arranged to assure that each aggregate as

removed from its stockpile is distinct and not intermingled with others. The concrete supplier

is asked to separate storage bins or compartments for each size and type of aggregate

properly constructed and charged to prevent mixing of different sizes or types

6 Sequencing and blending of the ingredients during charging of the mixers shall be carried out

in such a way as to obtain uniformity and homogeneity in the concrete produced as indicated

by such physical properties as unit weight, slump, air content, strength and air-free mortar

content in successive batches of the same mix proportions and as stated in ASTM C94

Annex A.

7 The mix recipe for the mixes to be produced shall be readily available to the mixer operator.

Only authorised personnel shall be allowed to make changes to the mix design.

8 All cement bags shall be stored in weathertight, properly ventilated structures to prevent

absorption of moisture.

9 Storage facilities for bulk cement shall include separate compartments for each type of

cement used. The interior of a cement silo shall be smooth, with a minimum bottom slope of

50 degrees from the horizontal for a circular silo and 55 to 60 degrees for a rectangular silo.

Silos shall be equipped with non-clogging air-diffuser flow pads through which small

quantities of dry, oil-free, low-pressure air can be introduced intermittently at approximately 3

to 5 psi (20 to 35 kPa) to loosen cement that has settled tightly in the silos. Storage silos shall

be drawn down frequently, preferably once per month, to prevent cement caking.

10 Each bin compartment from which cement is batched shall include a separate gate, screw

conveyor, air slide, rotary feeder, or other conveyance that effectively allows both constant

flow and precise cutoff to obtain accurate batching of cement

11 Fly ash, ground slag, or other pozzolans shall be handled, conveyed, and stored in the same

manner as cement. The bins, however, shall be completely separate from cement bins

without common walls that could allow the material to leak into the cement bin.

12 All bins and silos shall be properly tagged at silos, bins and near charging hose.

13 Bags of cement should be stacked on pallets or similar platforms to permit proper circulation

of air. For a storage period of less than 60 days, stack the bags no higher than 14 layers, and

for longer periods, no higher than seven layers.

14 The water batcher and the water pipes should be leak-free. If ice is used, the ice facilities,

including the equipment for batching and transporting to the mixer, should be properly

insulated to prevent the ice from melting before it is in the mixer.

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7.2.2 Plant Type

1 Manual control batching. Manual plants are acceptable for small jobs having low batching

rate requirements, generally for jobs up to a total concrete quantity of 1000 m3 and 10 m

3/h.

2 Semi-automatic control batching. In this system, aggregate bin gates for charging batchers

are opened by manually operated push buttons or switches. Gates are closed automatically

when the designated weight of material has been delivered.

3 Automatic control batching. Automatic batching of all materials is electrically activated by a

single starter switch. However, interlocks shall interrupt the batching cycle when the scale

has not returned to 0.3 % of zero balance or when weighing tolerances detailed in

Clause 7.2.5 of this Part are exceeded.

7.2.3 Bins and Weight Batchers

1 Batch plant bins shall be of sufficient size to effectively accommodate the production capacity

of the plant. Compartments in bins separate the various concrete materials, and the shape

and arrangement of aggregate bins shall prevent aggregate segregation and leakage.

2 Weight batchers shall be charged with easy-operating clam shells or undercut radial-type bin

gates.

3 Gates used to charge semi-automatic and fully automatic batchers shall be power operated

and equipped with a suitable in flight correction to obtain the desired weighing accuracy. They

shall be calibrated by the plant supplier for the types of aggregate used at the standard range

of moisture contents.

4 Weigh batchers shall be accessible for obtaining representative samples, and they shall be

arranged to obtain the proper sequencing and blending of aggregates during charging of the

mixer.

5 The amount of concrete mixed in any one batch shall not exceed the rated capacity of the

mixer.

6 All mixing and batching plants shall be maintained free of set concrete or cement and shall

be clean before commencing mixing.

7 For each different type of cement at use at the plant a separate silo shall be provided.

7.2.4 Tolerances of Measuring Equipment

1 Scales for weighing concrete ingredients shall be accurate when in use within 3 % and

1.5 % for additives. Standard test weights shall be available to permit the checking of scale

accuracy.

2 Testing of the weighers shall be at three-month intervals. If water is dispensed by flow meter

the frequency of testing shall be at three-month intervals. Such testing shall be undertaken by

a calibration company approved by the Central Materials Laboratory, and calibrated to

recognized international standards.

3 Test certificates shall be displayed in the plant in prominent positions.

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7.2.5 Batching Tolerances

1 Operation of batching equipment shall be such that the concrete ingredients are consistently

measured within the following tolerances. The plant shall have the ability to flag values that

are outside these limits. The operator shall make manual adjustments to the batching and

the final weights shall be within the given limits stated in table 7.1. Any adjustments shall be

displayed on the batch weight printouts.

2 Cementitious materials shall be measured by mass. When supplementary cementitious

materials are used in the concrete mixtures, the cumulative mass is permitted to be

measured with hydraulic cement, but in a batch hopper and on a scale which is separate and

distinct from those used for other materials.

3 Aggregate shall be measured by mass. Batch mass measurements shall be based on dry

materials and shall be the required masses of dry materials plus the total mass of moisture

(both absorbed and surface) contained in the aggregate

4 Mixing water shall consist of water added to the batch, ice added to the batch, water

occurring as surface moisture on the aggregates, and water introduced in the form of

admixtures. The added water shall be measured by weight or volume.

5 Added ice shall be measured by weight. In the case of truck mixers, any wash water retained

in the drum for use in the next batch of concrete shall be accurately measured; if this proves

impractical or impossible the wash water shall be discharged prior to loading the next batch

of concrete

6 Chemical admixtures in powdered form shall be measured by mass. Liquid chemical

admixtures shall be batched by mass or volume

Table 7.1

Typical batching tolerances Ingredient

Typical batching

tolerances

Ingredient

Batch weights greater than

30% of scale capacity

Batch weights less than

30% of scale capacity

Individual

batching

Cumulative

batching

Individual

batching

Cumulative

batching

Cement and other

cementitious

Materials

±1% of required mass or

±0.3% of scale capacity,

whichever is greater

Not less than required weight or 4%

more than required weight

Water (by volume or

weight), % ±1

Not

recommended ±1 Not recommended

Aggregates, % ±2 ±1 ±2

±0.3% of scale

capacity or

±3% of required

cumulative

Weight, whichever is

less

Admixtures (by

volume or weight), % ±3

Not

recommended ±3 Not recommended

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7 Cement supplied in bags shall be placed directly from the bag into the intake of the mixing

plant and each batch must contain one or more complete bags of cement. No mixer having

a rated capacity of less than a one-bag batch shall be used and the mixer shall not be

charged in excess of its rated capacity.

7.2.6 Charging the Mixer

1 Each batch shall be so charged into the mixer that some of the water will enter in advance of

the cement and aggregates. Controls shall be provided to prevent batched ingredients from

entering the mixer before the previous batch has been completely discharged.

2 The first batch of concrete through the mixer shall contain an excess of cement to allow for

coating of the inside of the mixing drum without reducing the required mortar content of the

mix.

3 Mixing plant that has been out of action for more than 30 minutes shall be thoroughly cleaned

before any fresh concrete is mixed in it.

4 When a change of mix is made to one using a different type of cement, the mixing plant shall

be thoroughly cleaned of all traces of the previously used cement, whatever is the time

interval between successive mixes.

7.3 MIXING

7.3.1 Charging Concrete Materials

1 Water shall enter the mixer first with continuous flow while other ingredients are entering the

mixer. Water charging pipes must be of the proper design and of sufficient size so that water

enters at a point well inside the mixer and charging is completed within the first 25% of the

prescribed mixing time and where concrete uniformity shall be verified by approved inspector.

2 Admixtures shall be charged to the mixer in accordance with the instructions of the

manufacturer. Automatic dispensers shall be used.

7.3.2 Mixing Time for Stationary Mixers

1 The mixing time required shall be based upon the ability of the mixer to produce uniform,

homogeneous, consistent mixture throughout the batch and from batch to batch.

2 Final mixing times shall be based on the results of mixer performance tests made at the start

of the project and the time fixed unless a change is authorised by the Engineer. The time

shall however not be less than 60 Sec unless otherwise verified as stated hereafter. Where

no mixer performance tests are made, the acceptable mixing time for mixers having

capacities of 0.75 m3 or less shall be not less than 1 min. For mixers of greater capacity, this

minimum shall be increased 15 s for each cubic meter or fraction thereof of additional

capacity.

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3 Where mixer performance tests have been made on given concrete mixtures in accordance

with the testing program ASTM C94 Annex A and NRMCA certification, and the mixers have

been charged to their rated capacity, the acceptable mixing time is permitted to be reduced

for those particular circumstances to a point at which satisfactory mixing defined in ASTM

C94 and NRMCA certification for central mixing plants shall have been accomplished. When

the mixing time is so reduced the maximum time of mixing shall not exceed this reduced time

by more than 60 s for air-entrained concrete. The mixing time shall be measured from the

time all ingredients are in the mixer.

4 Batch mixers with audible indicators used in combination with interlocks which prevent mixer

discharge prior to completion of a preset mixing time shall be provided on automatic plants

and are also desirable on manual plants.

5 The mixer shall be designed for starting and stopping under full load.

7.3.3 Mixing

1 All structural concrete to be placed in-situ shall be manufactured in a computer controlled

batching plant of the types described in Clause 7.2.2 of this Part.

2 The plant shall be complete with suitable water chilling or ice making facilities, or both, to

ensure concrete temperatures are maintained as specified in Parts 6 and 15 of this Section.

3 Concrete shall be mixed in batches in plant capable of combining the aggregates, cement

and water (including admixtures, if any) into a mixture of uniform colour and consistency and

of discharging the mixture without segregation.

4 Automatic moisture content probes, set in the hoppers shall be used to continuously

determine the moisture content of the aggregates.

5 Contractor shall make due allowance for the water contained in the aggregates when

determining the quantity of water to be added to each mix.

6 The amount of water added to each mix shall be adjusted to maintain the constant approved

water : cement ratio of the mixed concrete.

7.3.4 Limitation of Water : Cement Ratio

1 No concrete shall exceed the water : cement ratio as given in Part 6 of this Section.

2 The quantity of water used in mixing shall be the least amount that will produce a workable

homogeneous plastic mixture which can be worked into the forms and around the

reinforcement.

3 Excess water over the maximum allowed by the mix design shall not be permitted and any

batch containing such excess will be rejected.

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7.4 READY-MIXED CONCRETE

7.4.1 General

1 The manufacture of readymix concrete for use in government projects may only be carried

out in batching plants that have an approval certificate issued by the Central Materials

Laboratory. When this certificate is under renewal process by the readymix concrete

manufacturer, other certificate such as NRMCA shall be considered by the Engineer as

approval on the uniformity and consistency of the facility. The engineer may request to re-

validate the uniformity tests under his supervision. In addition, the use of readymix concrete

in any part of the work shall require the Engineer’s written approval.

2 The Contractor shall satisfy the Engineer on the following:

(a) materials used in ready-mixed concrete comply with the specification in all respects

(b) manufacturing and delivery resources of the proposed supplier are adequate to ensure

proper and timely completion.

3 The specified requirements as to the sampling, trial mixing, testing and quality of concrete, of

various grades as described in Part 6 of this Section, shall apply equally to ready-mixed

concrete.

4 Every additional facility, including but not limited to testing equipment, labour, laboratory

facilities and transport, which the Engineer or persons authorised by him may require for the

supervision and inspection of the batching, mixing, testing and transporting to Site of ready-

mixed concrete shall be provided by the Contractor at no extra cost.

5 Copies of all delivery notes shall be submitted to the Engineer in duplicate, on computer

generated forms and shall include at least the following information.

(a) name of supplier, serial number of ticket and date

(b) truck number

(c) name of Contractor

(d) name of Contract and location of office

(e) grade of concrete

(f) specified workability

(g) type and source of cement

(h) source of aggregate

(i) nominal maximum size of aggregate

(j) quantity of each concrete ingredient

(k) type of admixture and quantity

(l) water content

(m) time of loading and departure from ready-mix plant

(n) arrival and departure times of truck

(o) time of completion of discharge

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(p) notations to indicate equipment was checked and found to be free of contaminants

prior to batching.

6 A copy of the delivery note shall be given to the Engineer's site representative for each load.

7 Unless approved otherwise in advance of batching all concrete of single design mix for any

one day's pour shall be from a single batch plant of a single supplier.

8 Ready-mix concrete shall conform to BS 8500 in addition to GSO EN 206-1, except

materials, testing and mix design shall be as specified in this Section.

9 Transit mixers equipped with automatic devices for recording the number of revolutions of

the drum shall be used.

10 Excess water over the maximum allowed by the mix design shall not be added.

11 Each mixer truck shall arrive at the job site with its water container full.

12 In the event that a container is not full or concrete tests give a greater slump than acceptable,

the load shall be rejected.

13 Shade temperature and concrete temperature shall be recorded at the point of discharge of

the mixer and at placement for each load of concrete delivered to site.

14 Maximum and minimum temperatures and wet bulb temperatures shall be recorded daily.

15 Slump tests shall be performed in accordance with BS EN 12350 or relevant GSO standard

at the point of placement as stated in Part 6.

16 No water shall be added at the Site.

END OF PART

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7.5 APPENDIX A: CONCRETE PLANT INSPECTION – CHECKLIST

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Page 12 of 15

Qatar General Organization for Standards and Standardization

CONCRETE PLANT INSPECTION CHECK LIST

New Approval ☐ Renewal ☐ Regular Inspection ☐

1.0 GENERAL INFORMATION OF PLANT

1.1 Company Name :

1.2 Inspection Date : AM / PM

1.3 Plant Location :

1.4 Plant No/s :

1.5 Plant Manufacturer :

1.6 Plant ID No. :

1.7 Approval Certificate No :

1.8 Contact a Plant :

2.0 FACTORY CONDITION

2.1 Concrete Floor Under Mixer and silos Yes ☐ No ☐

2.2 Concrete floor with Slope under materials Yes ☐ No ☐

2.3 Hard and stable surface for Access and ramps Yes ☐ No ☐

2.4 Floors Clean Yes ☐ No ☐

2.5 Cleaning plan implements Yes ☐ No ☐

2.6 Drainage System Yes ☐ No ☐

2.7 Separated Place of Waste materials Yes ☐ No ☐

2.8 Separated Place of wash tank Yes ☐ No ☐

3.0 MATERIAL STORAGE AND HANDLING

3.1 Cement and Cementations materials (including blended cements, fly ash, GGBS, silica fume..)

3.1.1 The Silos of Cement

A. Outside Cleaning for Cement silo Yes ☐ No ☐

B. Cement scale calibration Current ☐ Expired ☐

C. Reflective color for cement silo Yes ☐ No ☐

D. Board clarify the cement type Yes ☐ No ☐

3.1.2 The silos of cementations materials

A. Outside Cleaning for Cementations silo Yes ☐ No ☐

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Page 13 of 15

B. Cementations scale calibration Current ☐ Expired ☐

C. Reflective Color for Cementations Silo Yes ☐ No ☐

D. Board Clarify the Cementations Type Yes ☐ No ☐

E. All Cementations Materials Excess of use protected under shad

Yes ☐ No ☐

3.2 Aggregates:

A. Aggregate Shading Yes ☐ No ☐

B. Aggregate Separation under shad Yes ☐ No ☐

C. Aggregate Separation in bins Yes ☐ No ☐

D. Aggregate scale calibration Current ☐ Expired ☐

E. Cover for Conveyer Belts Yes ☐ No ☐

F. Board Clarify the Aggregate Type Yes ☐ No ☐

G. Effective method for checking the level of material inside the bins

Yes ☐ No ☐

4.0 Water & Admixture Supply

4.1 Water supply

A. Water pipe insulated Yes ☐ No ☐

B. Chiller using Yes ☐ No ☐

C. Ice plant or Nitrogen cooling Yes ☐ No ☐

D. Water gauge calibration Current ☐ Expired ☐

4.2 Admixture supply

A. Additive storage silos Yes ☐ No ☐

B. Additive Gage calibration Current ☐ Expired ☐

C. Board Clarify the Admixture Type Yes ☐ No ☐

D. All admixture excess of use protected under shad

Yes ☐ No ☐

E. Agitation system for all storage tanks or silos more than 5000 liter

Yes ☐ No ☐

5.0 Requirements of the Concrete batching plant

5.1 Certificate validity Yes ☐ No ☐

5.2 Computer controlled Yes ☐ No ☐

5.3 Plant type Wet mix ☐ Dry mix ☐

5.4 Computer printout Yes ☐ No ☐

5.5 Calibration validity Current ☐ Expired ☐

5.6 Cleaning of plant blades Yes ☐ No ☐

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Page 14 of 15

6.0 Laboratory

6.1 Records for raw materials and cube tests

Required Tests to QCS 2014 Was Test

Performed?

Frequency of Tests Comments of Inspection

D W M

6.1.1 Grading Yes ☐ No ☐

6.1.2 Fines content (%) Yes ☐ No ☐

6.1.3 Fines quality Yes ☐ No ☐

6.1.4 Clay lumps and friable particles

Yes ☐ No ☐

6.1.5 Lightweight pieces Yes ☐ No ☐

6.1.6 Organic impurities Yes ☐ No ☐

6.1.7 Water Absorption Yes ☐ No ☐

6.1.8 Particle density Yes ☐ No ☐

6.1.9 Shell Content Yes ☐ No ☐

6.1.10 Flakiness Index (%) Yes ☐ No ☐

6.1.11 Chloride content (%) Yes ☐ No ☐

6.1.12 Sulphate content (%) Yes ☐ No ☐

6.1.13 Soundness (%) Yes ☐ No ☐

6.1.14 Los Angeles abrasion Yes ☐ No ☐

6.1.15 Moisture Content (%) Yes ☐ No ☐

6.1.16 Compressive Strength Yes ☐ No ☐

6.1.17 Other test*

*Such as recycled aggregate

6.2 Specimens testing at inspection time

ITEMS CASE COMMENTS

6.2.1 Method of slump test Yes ☐ No ☐

6.2.2 Curing of samples Yes ☐ No ☐

6.2.3 Water Temperature Of Curing Tank Yes ☐ No ☐

6.2.4 Concrete Temperature at plant Yes ☐ No ☐

6.2.5 Concrete Slump at plant Yes ☐ No ☐

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Page 15 of 15

6.3 Laboratory equipment calibration

EQUIPMENT CASE COMMENTS

6.3.1 Compression Testing Machine Yes ☐ No ☐

6.3.2 Sieves Yes ☐ No ☐

6.3.3 Balance Yes ☐ No ☐

6.3.4 Thermometers Yes ☐ No ☐

7.0 Recommendations

8.0 Plant representative information

Name of representative :

Contract number :

Signature :

9.0 Inspector team

Inspected by Signature

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QCS 2014 Section 05: Concrete Page 1 Part 08: Transportation and Placing of Concrete

8 TRANSPORTATION AND PLACING OF CONCRETE ............................................ 2

8.1 GENERAL ............................................................................................................... 2

8.1.1 Scope of Work 2

8.1.2 References 2

8.1.3 Submittals 2

8.2 TRANSPORTATION ............................................................................................... 3

8.2.1 General 3

8.2.2 Pumped Concrete 3

8.2.3 Records 4

8.3 PLACING CONCRETE ............................................................................................ 4

8.3.1 General 4

8.3.2 Preparation 4

8.3.3 Placing 5

8.3.4 Compaction 7

8.3.5 Continuity of Concrete Work 8

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8 TRANSPORTATION AND PLACING OF CONCRETE

8.1 GENERAL

8.1.1 Scope of Work

1 This part deals with the transportation, placing and compaction of concrete.

2 Related Parts are as follows:

This Section

Part 1 ............... General


Part 9, .............. Formwork

Part 15, ............ Hot Weather Concreting

Part 16, ............ Miscellaneous

8.1.2 References

ACI 304, ............. Guide for Measuring, Mixing, Transporting, and Placing Concrete

ASTM C94, ......... Specification for ready-mixed concrete

BS 8500, ............. Concrete, Complementary British Standard to BS EN 206-1.

BS EN 206-1, ..... Concrete. Specification, performance, production and conformity

EN 1992-1-1 ....... Eurocode 2: Design of concrete structures. General rules and rules for

buildings

8.1.3 Submittals

1 Should the Contractor propose to use concrete pumps for the transportation and placing of

concrete, he shall submit details of the equipment and operating techniques he proposes to

use for the approval of the Engineer.

2 A method statement shall be submitted for approval for major concrete placements, which

shall address

(a) the planned rate of placing

(b) number of batching plants

(c) number of trucks

(d) number and positioning of pumps

(e) pour sequence

(f) quality control measures

(g) spare equipment

(h) any other factors that might affect the placing of concrete.

3 The method statement should be submitted at least three days in advance of the planned

pour. If required by the Engineer or any other concerned party a prepour planning meeting

may be arranged with representatives from the ready-mix supplier, Contractor and Engineer.

4 The Contractor shall submit to the Engineer for approval details of his proposed operations

and standby equipment.

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8.2 TRANSPORTATION

8.2.1 General

1 Transportation delivery and handling shall be in accordance with the requirements of BS

8500 and BS EN 206-1.

2 Concrete shall be conveyed from the mixer to its place in the Works as rapidly as possible by

methods which will prevent segregation or drying out and ensure that the concrete is of the

required workability at the point and time of placing.

3 Should segregation occur in the concrete then the materials shall be remixed to the

satisfaction of the Engineer or discarded. Furthermore the cause of the segregation shall be

determined and further occurrences prevented.

4 The Contractor shall ensure that the time between placing of different lifts or layers of

concrete is short enough to prevent the formation of cold joints. The Contractor shall ensure

that there is a back up plant that can be used in the event of a breakdown, and that adequate

provision has been made for the number of delivery trucks.

5 The concrete shall be transported to the site in an approved type of truck mixer or agitator

truck which apart from the cab and chassis shall be painted white and kept clean at all times.

The discharge chute and other dirty areas shall be washed down after delivery to prevent

spillage on the roads.

6 If a truck mixer or a truck body with an agitator is used for central-mixed concrete, limit the

volume of concrete charged into the truck to 80% of the drum or truck volume as per ASTM

C94 and NRMCA requirements. if shrink mixing is approved by the engineer limit the volume

of concrete charged into the truck to 63% of the drum volume.

7 All trucks shall be rotated 30 revolutions at mixing speed before discharging concrete to

assure uniformity.

8 The insides of concrete mix trucks shall be inspected periodically, and any build up of

concrete removed that may impair the efficiency of the mixing action. All trucks shall be

NRMCA certified or any equivalent certification

9 Discharge of the concrete shall be completed within 90 min, or before the drum has revolved

300 revolutions, whichever comes first, after the introduction of the mixing water to the

cement and aggregates or the introduction of the cement to the aggregates. These limitations

are permitted to be waived by the purchaser if the concrete is of such slump or slump flow

after the 90 min time or 300-revolution limit has been reached that it can be placed, without

the addition of water, to the batch. In hot weather, or under conditions contributing to quick

stiffening of the concrete, a time less than 90 min is permitted to be specified by the Engineer

8.2.2 Pumped Concrete

1 Access for the pump shall be checked prior to the pour. If access cannot be assured, the

Contractor shall not continue with concreting operations.

2 If approval is obtained for pumped concrete, the Contractor shall ensure that shock is not

transferred from the pipeline to the formwork and previously laid concrete.

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3 During placing concrete by pumping the end hose must never reach into the concrete. All

measures shall be taken to avoid blockage of the delivery hose system. The Compaction of

concrete shall be carried out as per standard practice procedures.

4 Grout shall be pumped through the concrete pump to provide initial lubrication. The initial

discharge of any pumped concrete shall not be incorporated in the permanent works.

5 Where concrete is conveyed by chuting or pumping the plant shall be of a size and design to

ensure continuous flow in the chute or pipe. The slope of the chute or the pressure of the

pump shall allow the concrete to flow without the use of any water additional to that approved

by the Engineer to produce the required consistency and without segregation of the

ingredients. The delivery end of the chute or pipe shall be thoroughly flushed with water

before and after each working period and kept clean. The water used for this purpose shall

be discharged outside and away from any permanent works.

8.2.3 Records

1 Within 24 h of delivery, the Contractor shall provide the Engineer with delivery notes giving

the information required under Paragraph 7.4.1.5 of this Section.

8.3 PLACING CONCRETE

8.3.1 General

1 The Contractor shall obtain the approval of the Engineer to his proposed arrangements

before beginning concreting.

2 All placing and compacting of concrete shall be carried out under the direct supervision of a

competent member of the Contractor’s staff with a minimum of five years of experience in

concreting works, and in a manner to produce a watertight concrete of maximum density and

strength.

3 For night concreting operations, the Contractor shall arrange adequate suitable lighting.

4 The Contractor shall provide safe secure access for all personnel on concreting operations.

5 Where the thickness of the concrete section exceeds 600 mm the Contractor shall adopt

special precautions, to be approved by the Engineer, to avoid thermal cracking due to

external and core temperature differentials.

6 Concrete shall not be placed in adverse weather conditions such as dust storms or heavy

rain.

8.3.2 Preparation

1 No concrete shall be placed until the Engineer has inspected and approved in writing the

surfaces upon which the concrete is to be placed, the formwork, and reinforcing steel. The

Contractor shall give the Engineer at least 24 hours notice to enable this inspection to be

carried out. If concrete is not placed within 24 hours of approval being given, approval shall

be obtained again before concreting. An inspection shall be made immediately prior to

concreting to check the cleanliness of the forms.

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2 Wood forms, unless lined, shall be oiled or wetted with water in advance of placing concrete

so that joints will tighten and prevent seepage of cement grout from the mix.

3 The reinforcement shall be sprayed with a small amount of water prior to starting the pour.

Reinforcement shall be secured in position, inspected, and accepted by the Engineer before

placing the concrete.

4 All inserts, anchor bolts, sleeves and other embedded items shall be accurately located,

using templates where appropriate, and held securely to prevent displacement during the

placing of the concrete. Aluminium items shall be completely covered and protected when

embedded in the concrete.

5 Except where shown on the drawings, no fixtures shall be attached to the concrete by shot

fixing or drilling without acceptance by the Engineer. Notwithstanding any such authorisation,

the Contractor shall be responsible for all damage so caused to the concrete and make good

at his own expense.

6 Water shall be removed from excavations before concrete is deposited. Any flow of water

shall be diverted through proper side drains and shall be removed without washing over

freshly deposited concrete. All dewatering works shall be continued as long as required.

Hardened concrete, debris, and foreign materials shall be removed from interior of forms and

from inner surfaces of mixing and conveying equipment.

7 Runways or other means accepted by the Engineer shall be provided for wheeled equipment

to convey the concrete to the points of deposit. Equipment used to deposit concrete shall not

be wheeled over reinforcement nor shall runways be supported on reinforcement.

8 Before depositing new concrete on or against concrete that has set, existing surfaces shall

be thoroughly roughened and cleaned of laitance, foreign matter and loose particles. Forms

shall be re-tightened and existing surfaces slushed with a grout coat of mortar consisting of

cement and fine aggregate in the same proportion in the mix, but not leaner than one (1) part

cement to two (2) parts fine aggregate, after the existing surface has been moistened. New

concrete shall be placed before the grout has attained initial set. Horizontal construction

joints shall be given a brush coat of grout consisting of cement and fine aggregate in the

same proportion as concrete to be placed, followed by approximately 75mm of concrete of

regular mix, except that the proportion of coarse aggregate shall be reduced 50%.

9 High strength grout for precision support of machine base and soleplates, including

equipment subject to thermal movement, tanks, column baseplates, bridge seats, anchor

bolts and dowels, etc., shall be a non-shrink, ready-to-use, fluid precision grout material,

proportioned, premixed and packaged at the factory, delivered to the job site to be placed

with only the addition of water, formwork, and curing shall be as specified.

8.3.3 Placing

1 Concrete shall be placed in its final position before initial set has commenced and shall not

be subsequently disturbed. All concrete shall be placed within 15 min of mixing unless carried

in purpose made agitators.

2 Concrete shall be carefully placed in horizontal layers which shall be kept at an even height

throughout the work. The depth of layers and time between placement of layers shall be such

that each layer can be properly merged into the preceding layer before initial set takes place,

the depth of layer shall be determined from the type of plant the Contractor proposes to use.

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3 Concrete shall be allowed to slide or flow down sloping surfaces directly into its final position

from skips, down pipes or other placing machines or devices or, if this is not practical, it

should be shovelled into position, care being taken to avoid separation of the constituent

materials.

4 Concrete placed in horizontal slabs from barrows or other tipping vehicles shall be tipped into

the face of the previously placed concrete.

5 Concrete dropped into place shall be dropped vertically. It shall not strike the formwork

between the point of its discharge and its final place in the Work, and except by approval of

the Engineer it shall not be dropped freely through a height greater than 1.5 m. Chutes and

conveyor belts shall be also designed so that there is no segregation or loss of mortar and

shall be provided with a vertical tapered down pipe, or other device, to ensure that concrete is

discharged vertically into place.

6 Concrete shall not be placed in standing water in the formwork.

7 Concrete that has attained its initial set or has contained its water content for more than 1.5

hours or 300 drum revolutions, whichever comes first, shall not be deposited in the work.

8 Cold weather concreting shall be in accordance with EN 1992-1-1 or CIRIA Report 67 and

ACI 306.

9 Hot weather concreting shall be in accordance with Part 15 of this section.

10 Special care shall be taken to protect new concrete from the harmful effects of drying winds.

11 During wet weather, the concrete shall be adequately protected as soon as it is in position.

12 No concreting shall be carried out during periods of continuous heavy rain unless it is

completely covered during mixing, transporting and placing.

13 No concrete shall be carried out during dust storms.

14 Underwater placing of concrete is allowed only for unreinforced components, the placing

being effected exclusively with stationary tremies or with a bottom-opening watertight boxes

and shall be in accordance with the requirements of design or equivalent as accepted.

15 Underwater concrete is to be placed continuously without interruption. For water depths up to

1 m the concrete may be placed without tremie. In the case of water depths exceeding 1 m

the concrete is to be placed in such a way that it does not fall freely through the water. The

tremies must at all times dip sufficiently far into the freshly placed concrete to ensure that the

concrete emerging from the tremie does not come into contact with the water.

16 All work connected with the placing of concrete under water shall be designed, directed and

inspected with due regard to local circumstances and purposes. Work shall not proceed until

all phases and methods to be used in the placing operations have been accepted by the

Engineer.

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17 Stops in concrete, at the end of a period of work, shall be made only at construction joint

locations shown on the drawings and/or positions accepted. Where the positions of

construction joints are not indicated on the drawings, these may be assumed, for estimating

purposes, to occur at 5 metre intervals in foundations and retaining walls and at one-third to

one-quarter of span in slabs and beams subject to a maximum spacing of approximately 9

metres.

18 At construction joint location the surface of the completed concrete shall be prepared by

spraying, wire brushing or chipping so that it is free from all laitance, scum and loose material

and shows a slightly roughened texture and tips of the coarse aggregate exposed. Before

continuing concreting the exposed concrete face shall be thoroughly wetted.

19 In the ground floor slab (where ground bearing), construction joints, crack inducer joints,

contraction joints and expansion joints shall be incorporated into the work as appropriate.

The spacing of construction joints, crack induced joints, contraction joints and expansion

joints in water retaining structures shall be shown on the design drawings

20 Where the positions or type of joints are not indicated on the drawings in the ground floor

slab, the slab shall be cast in strips not more than 4.0 metres wide, in alternating sequence,

across the width of the building. A minimum of 3 days shall elapse between the casting of

adjacent strips. Within each strip, crack induced joints shall be provided at not more than 5.0

metre spacing, and contraction joints shall be provided at not more than 15.0m spacing.

Across the width of the building, construction joint shall be provided between adjacent strips

with contraction joint at every 4th construction joint.

21 Wherever necessary and as required by the Engineer, waterstops of a type acceptable to the

Engineer shall be embedded in the concrete. The waterstop should be made of a high

quality material, which must retain its resilience through the service life of the structure for the

double function of movement and sealing. The surface of waterstops should be carefully

rounded to ensure tightness of the joint even under heavy water pressure. To ensure a good

tightness with or without movement of the joints, the waterstop should be provided with

anchor parts. The cross-section of the waterstops should be determined in accordance with

the presumed maximum water pressure and joint movements. The complete works of fixed

and welded connections must be carried out strictly in accordance with the manufacturer’s

instructions.

22 Engineer’s acceptance shall be obtained by the Contractor, prior to start of work, on the

casting sequence and the layout of joints.

23 Waterstops shall be carefully maintained in position prior to concreting on accurately profiled

stop boards to create rigid conditions.

24 The type of waterbar to be used shall suit the joint and purpose according to water bar

manufacturers recommendations

8.3.4 Compaction

1 Concrete shall be thoroughly compacted by vibration during the operation of placing and

thoroughly worked around the reinforcement, around embedded fixtures and into corners or

the formwork to form a solid mass free from voids.

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2 When vibrators are used to compact the concrete, vibration shall be applied continuously

during the placing of each batch of concrete until the expulsion of air has practically ceased

and in a manner that does not promote segregation of the constituents of the concrete.

3 Immersion type vibrators shall be capable of producing not less than 10000 cycles per

minute, and external vibrators not less than 3000 cycles per minute.

4 A sufficient number of vibrators in serviceable condition shall be on site to ensure that spare

equipment is always available in the event of breakdown.

5 Immersion type vibrators shall be inserted into the uncompacted concrete vertically and at

regular intervals. Where the uncompacted concrete is in a layer above freshly compacted

concrete the vibrator shall penetrate vertically for about 100 mm into the previous layer.

Vibrators shall not come into contact with the reinforcement or the formwork. They shall be

drawn back slowly from the mass concrete so as to leave no voids. Internal type vibrators

shall not be placed in the concrete in a random or haphazard manner nor shall concrete be

moved from one part of the work to another by means of the vibrators.

6 Operators shall be trained in the use of vibrators. Foremen shall have a minimum of five

years of experience in the supervision of placing concrete

7 Vibration of the concrete shall not be applied by way of the reinforcement.

8 Compaction shall commence as soon as there is sufficient concrete to immerse the vibrator

and continue during the placing operations so that at no time shall there be a large volume of

uncompacted concrete in the formwork.

9 The duration of vibration shall be limited to that required to produce satisfactory compaction

without causing segregation. Vibration shall on no account be continued after water or

excess grout has appeared on the surface.

10 During the placing of all reinforced concrete, a competent steel fixer and a competent

carpenter shall be in attendance on each concreting gang. They shall ensure the

reinforcement embedded fittings and forms are kept in position as work proceeds.

8.3.5 Continuity of Concrete Work

1 Whenever instructed by the Engineer, the Contractor shall carry out the work in such a

manner that the placing of the concrete in any particular section of the structure shall be

executed without any interruption whatsoever from the beginning to the end of the operation.

2 Casting of concrete shall not begin until a sufficient quantity of approved material is at hand

to ensure continuity of operation, nor shall work begin until there is sufficient equipment in

reserve in case of breakdown.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 09: Formwork

9 FORMWORK ........................................................................................................... 2

9.1 GENERAL ............................................................................................................... 2 9.1.1 Scope 2 9.1.2 References 2 9.1.3 Submittals 2 9.1.4 Quality Assurance 3

9.2 FORMWORK MATERIALS ...................................................................................... 5 9.2.1 General 5

9.3 CLASS OF FINISH AND MATERIALS: .................................................................... 5 9.3.1 Unformed surfaces 5 9.3.2 Surface Finish Classifications 7 9.3.3 Formwork Materials 7 9.3.4 Exposed Concrete Surface Finishes 7 9.3.5 Form Ties 8 9.3.6 Coating and Accessories 8

9.4 FORMWORK EXECUTION ..................................................................................... 9 9.4.1 General 9 9.4.2 Trial Panels 9 9.4.3 Formwork Face in Contact with Concrete 9 9.4.4 Sloping Surfaces 10 9.4.5 Temporary Openings 10 9.4.6 Form Windows 10 9.4.7 Co-ordination 10 9.4.8 Conduits 10 9.4.9 Ties and Bolts 11 9.4.10 Chamfers 11 9.4.11 Cambers 11 9.4.12 Exterior Angles 11 9.4.13 Surface Retarders 11 9.4.14 Detection of Movement During Concrete Placement 11 9.4.15 Building in Pipes 12 9.4.16 Working Platform 12 9.4.17 Safe Access 12 9.4.18 Kickers 12 9.4.19 Cover Spacers 12 9.4.20 Water Bars 12

9.5 REMOVAL OF FORMWORK................................................................................. 13 9.5.1 General 13 9.5.2 Stripping of Formwork 13 9.5.3 Holes to be Filled 14 9.5.4 Repair to Damaged Concrete Surfaces 14

9.6 DELIVERY AND STORAGE .................................................................................. 14 9.6.1 Delivery 14 9.6.2 Storage 14

9.7 TOLERANCES ...................................................................................................... 15

9.8 EARLY LOADING .................................................................................................. 15

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9 FORMWORK

9.1 GENERAL

9.1.1 Scope

1 This Part includes permanent forms, temporary formwork, and falsework for structural and

architectural cast-in-place concrete including form liners, coatings, and accessories.


This Section

Part 8, .............. Transportation and Placing of Concrete

Part 10, ............ Curing

Part 17, ............ Structural Precast Concrete.

Section 11: Health and Safety

Part 1, ............. Regulatory document

Part 2, ............. Safety and accident prevention management/administration system

(SAMAS)

9.1.2 References

1 The following standards and other document are referred to in this Part:

ACI Committee 117 .... “Standard Tolerances for Concrete Construction and Materials” (ACI

117-90), American Concrete Institute, Detroit, 22 pp.

ACI Manual of Concrete Practice, Parts 2 and 5.

BS 8500 ...................... Concrete

BS 5975 ...................... Code of practice for false work

BS EN 12812 .............. Falsework. Performance requirements and general design CP3

chapter V-2: 1972

EN 1992-1-1 ............... Eurocode 2: Design of concrete structures. General rules and rules for

buildings

GSO EN 206-1 ........... Concrete. Specification, performance, production and conformity

Concrete Society Technical Report No. 13

9.1.3 Submittals

1 Shop drawings shall include plans and sections, giving the following minimum information for

each level:

(a) details of individual panels

(b) position, size and spacing of adjustable steel shores

(c) position, size and spacing of joists, soldiers, ties

(d) details of formwork for columns, beams, parapets, slab and kickers

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(e) details of construction joints and movement joints

(f) details of retaining walls and deep beams showing the position and size of ties, joints,

soldiers and sheeting, together with detailed information on erection and casting

sequences and construction joints

(g) general assembly details

(h) full calculation sheets

(i) proposals at all penetrations through the concrete

(j) proposed sequence of shoring and reshoring beams and slabs for different spans and

floor heights and number of floors shored, and the stripping time for supported and

suspended structural elements, clearly identifying the supported element and

suspended element.

2 Scales of shop drawings shall be as follows:

(a) details: 1:1, 1:5, 1:10, 1:20

(b) construction: 1:50, 1:100

(c) layout and Site Plan: 1:100 or 1:200

3 The Contractor shall submit samples of all proposed formwork materials and samples of ties

proposed for use in general situations above the water table and for fair faced concrete.

4 The Contractor shall allow 14 days for Engineer’s review of submittals or samples.

5 Supply and delivery of built-in pipework should be clearly shown on the detailed construction

program to be submitted by the Contractor.

6 Method Statements for erection and removal of formwork shall be submitted by the

Contractor before the start of the works for the Engineer’s review and approval. The Method

Statement shall include the Risk Assessments related to the activity.

7 When the formwork is to be carried out by a sub-contractor, then the pre-qualification

documents shall be submitted for the Engineer’s review and approval.

9.1.4 Quality Assurance

1 Formwork shall comply with the requirements of BS 5975 and EN 1992-1-1

2 The erection of formwork and associated falsework shall be executed and supervised by fully

qualified personnel having a minimum of five years experience.

3 The Contractor shall obtain approval to load any particular section of the works from the

Engineer.

4 Formwork design shall be carried out in accordance with the Concrete Society Technical

Report No. 13.

5 The erected formwork shall be watertight from the ingress of external liquids and the egress

of internal liquids. Adjustable steel supports and shores shall allow formboards and

framework to be accurately adjusted to line and level. The Contractor shall ensure that

adequate ground support for falsework is available, and if not shall take measures to make

them suitable.

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6 Formwork shall be designed to be sufficiently rigid to maintain the correct position, shape and

profile so that the final concrete structure is within the dimensional tolerances specified

Subpart 9.7 of this Part.

7 Formwork shall be designed to be demountable without causing shock, disturbance or

damage to the concrete.

8 Soffit formwork, properly supported on shores only, shall be capable of being retained in

position during the concrete maturing period.

9 The design shall allow free movement and accessibility under the formwork.

10 Shores for abnormal ceiling heights shall be specially designed.

11 The forms shall be designed to incorporate 20 mm chamfers on exposed corners of

columns, walls and beams.

12 The design of formwork shall take into account the following:

(a) height and rate of pour

(b) thickness of the member

(c) concrete slump and density

(d) placing temperature

(e) texture of finish

(f) construction joints

(g) wind load

(h) on soffit forms (in addition to concrete weight)

(i) an additional live load of 2.5 kPa, or

(ii) if a motorised cart is used, an additional live load of 3.75 kPa

(i) minimum design load for combined dead and live load

(i) 6.50 kPa

(ii) if a motorised cart is used, 7.75 kPa

(j) the worst combination of:

(i) self-weight

(ii) formwork forces

(iii) reinforcement weight

(iv) wet concrete weight

(v) construction loads

(vi) wind loads,

(vii) incidental dynamic effects caused by placing, vibrating and compacting

concrete

(viii) the use of externally applied vibrators

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(k) method of concrete discharge

(l) access for concrete placement and vibration.

13 Before beginning related formwork operations the Contractor shall erect a job mock-up, to a

reasonable size including all items such as sheeting, stiffeners, soldiers, ties etc. (and

including release agents, where used) for the following types of formwork, and shall obtain

the approval the Engineer before proceeding:

(a) columns

(b) slabs and beams

(c) staircases

(d) fair-faced concrete (show method used to conceal tie holes) cove ties not required.

14 Upon prior consultation, agreement of location and approval, the job mock-ups may remain

as part of the finished work.

9.2 FORMWORK MATERIALS

9.2.1 General

1 Forms shall be of wood; metal or other material acceptable to the Engineer.

2 The design of formwork shall be the responsibility of the Contractor.

3 Formwork shall conform to the requirements of EN 1992-1-1

4 Form oil and form sealer shall be of quality as acceptable to the Engineer.

9.3 CLASS OF FINISH AND MATERIALS:

9.3.1 Unformed surfaces

1 Unformed surfaces shall be classified as either:

(a) U4, timber trowel finish

(b) U3, steel trowel finish

(c) U2, brush finished

(d) U1 other finish designated by the Engineer, such as:

(i) Screeded Finish - Where the floor slab is to receive a screeded finish, the slab

shall be laid to the slopes and levels shown on the drawings and the top surface

shall be tamped whilst unset, to produce a suitable keyed surface for the receipt

of the appropriate finishing materials.

(ii) Floated Finish - Where a floated finish is required to the floor slabs the top

surface shall be leveled and floated whilst unset to an uniform finish to the

slopes and levels shown on the drawings. The floating shall be done in such a

manner as not to bring an excess of mortar to the surface.

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(iii) Dustproof Finish - Where concrete surfaces are required to provide a dustproof

finish these shall be treated with two coats of accepted material. Each coat

shall be applied with a soft brush on a clean and dry surface in accordance with

the manufacturer's printed instructions.

(iv) Non-slip Finish - Concrete surfaces described on the drawings as having a non-

slip finish shall be treated with carborundum dust, evenly sprinkled on whilst the

concrete is still green, at a rate of 1½ kg/m² and lightly trowelled in before final

finishing. Alternatively, the carborundum dust may be incorporated into the finish

by means of a mechanical power float.

(v) Hardened Finish - Where a hardened finish is required to the floor slabs these

shall be treated with three coats of accepted material. Each coat shall be

applied with a soft brush on a clean and dry surface in accordance with the

manufacturer's printed instructions.

(vi) Finishing Unformed Surfaces - Finishing unformed surfaces shall be tamped,

floated, trowelled or brushed as defined below and shown on the drawings.

1. Type T - Tamped surfaces shall be formed by levelling and tamping the

concrete to produce a uniform plain or ridged surface, surplus concrete

being struck off by a straight edge immediately after compaction. It is

also the first stage of the following finish.

2. Type F - Floated surfaces shall be uniform surface which has been

worked no more than is necessary to remove screed marks by hand with

a wood float or by power float of a type acceptable to the Engineer. The

surface shall not be floated until the concrete has hardened sufficiently.

3. Type ST - Steel trowelled shall be a hard, smooth finish, free from trowel

marks and formed with a steel trowel under firm pressure. Trowelling shall

not commence until the moisture film has disappeared and the concrete

has hardened sufficiently to prevent excess laitance from being worked to

the surface. If laitance is brought to the surface it shall be removed.

4. Type BR - Brushed shall be formed before the concrete has hardened by

drawing a wire broom over the concrete surface at right angles to the

traffic flow to give an average texture depth of 1mm.

5. For ground slab concrete shall be treated with sodium silicate or a similar

dust preventive coating. This must be applied in accordance with the

manufacturer's instructions.

2 The type of finish will be specified on the drawings or as directed by the Engineer. Before

beginning any concrete pour with unformed surfaces, the Contractor shall obtain confirmation

of the type of finish required from the Engineer.

3 Initial finishing of unformed surfaces shall commence immediately after the placing and

compaction have taken place.

4 Suitable access boards or platforms shall be provided to allow access to all parts of

unformed surfaces to be finished.

5 Where a protective treatment or topping layer is to be applied to the concrete the

manufacturers and suppliers recommendations shall be followed concerning the required

finish.

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6 Brush to finish shall be obtained by carrying out a steel trial finish and then using a suitable

stiff nylon brush dragged lightly across the surface.

7 The addition of small quantities of water to the finishing trowel will be permitted to aid

finishing.

9.3.2 Surface Finish Classifications

1 Finishes to formed surfaces of concrete shall be classified as F1, F2 and F3, or such other

special finish as may be designated.

2 Where the class of finish is not designated:

(a) all internal concrete shall be finished to Class F3

(b) external concrete below ground shall be finished to Class F1

(c) where surfaces are to be tanked by covering with paint or sheeting, the formwork

shall be capable of achieving a finish suitable for the proposed tanking as directed by

the Engineer.

9.3.3 Formwork Materials

1 Formwork for Class F3 finish shall be lined with as large panels as possible of non-staining

material with a smooth unblemished surface such as sanded plywood or hard compressed

fibre board, arranged in a uniform approved pattern and fixed to back formwork by oval nails.

(a) the same type of lining shall be used throughout any one structure

(b) unfaced wrought boarding or standard steel panels shall not be permitted.

2 Formwork for Class F2 finish shall be faced with wrought tongued and grooved boards or

plywood arranged in a uniform approved pattern free from defects likely to detract from the

appearance of the surface.

3 Formwork for Class F1 finish shall be constructed of timber, or of any suitable materials

which will prevent loss of grout when the concrete is vibrated.

9.3.4 Exposed Concrete Surface Finishes

1 Exposed concrete surfaces shall have a Class F3 finish.

2 Care shall be taken to ensure that the finish to the exposed concrete on the external and

internal surfaces are of the highest quality to produce a smooth concrete surface of uniform

texture and appearance without visible imprint of grains, steppings or ridges.

3 The resulting concreting shall be free from honeycombing, stains, fins, lipping, nail and screw

marks, raised grain marks or any other imperfections and shall be of a uniform surface

texture and colour. Only very minor surface blemishes caused by entrapped air or water will

be accepted provided that they do not exceed 0.5% by area of each square metre considered

separately and in addition they shall not be concentrated in a manner such that they are

noticeable.

4 Formwork to the wetted surfaces of water retaining structures shall be Class F3

5 All exposed concrete corners and edges shall have 20 mm by 20 mm chamfers.

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6 Grooves in exposed concrete shall be formed by attaching tapered planed timber battens

accurately aligned to the face of formwork.

9.3.5 Form Ties

1 Form ties shall conform to the following requirements:

(a) factory-fabricated

(b) adjustable in length

(c) use removable or snap-off metal form ties

(d) designed to prevent formwork deflection and to prevent spalling concrete surfaces on

removal

(e) no metal shall be left closer than the applicable level of cover to the surface of the

concrete

(f) holes larger than 10 mm diameter in the concrete surface, when using snap ties shall

not be permitted

(g) form ties shall have a factor of safety not less than 1.5.

9.3.6 Coating and Accessories

1 Form coatings shall be commercial formulation form-coating compounds that will not bond

with, stain, nor adversely affect concrete surfaces requiring bond or adhesion, nor impede the

wetting of surfaces to be cured, shall be used. The use of form coatings shall be strictly in

accordance with the manufacturer instructions.

2 Formwork in contact with the concrete shall be treated with a suitable non-staining mould oil

to prevent adherence of the concrete.

3 Forms for exposed surfaces shall be coated with oil before reinforcement is placed. Forms

for unexposed surfaces may be thoroughly wetted with water in lieu of oiling, immediately

before placing of concrete except during freezing weather.

4 Excessive oiling of the forms shall not be permitted in order to prevent discoloration of the

cement plaster. Where concrete surface is to be painted, the form-oil must not affect the

bond between concrete and paint.

5 Care shall be taken to prevent the oil from coming in contact with reinforcement or with

concrete at construction joints. Any oil on reinforcing steel shall be removed.

6 Release agents shall not be used where concrete surfaces receive special finishes or applied

coatings which may be affected by the agent, unless approved by the Engineer.

7 Fillet and chamfer strips shall be PVC or timber to the approval of the Engineer.

8 Tapes to be used to seal joints of formwork panels for smooth finish concrete shall be plastic

faced adhesive tape to the approval of the Engineer.

9 Precast concrete moulds shall be rigid steel, wood or fibreglass moulds.

10 Flashing reglets shall be galvanised steel of the longest possible length.

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9.4 FORMWORK EXECUTION

9.4.1 General

1 Where formwork to external faces will be permanently exposed, all horizontal and vertical

formwork joints shall be so arranged that joint lines will form a uniform pattern on the face of

the concrete.

2 Where the Contractor proposes to make up the formwork from standard sized manufactured

formwork panels, the size of such panels shall be approved by the Engineer before they are

used in the construction of the Works.

3 The finished appearance of the entire elevation of the structure and adjoining structures shall

be considered when planning the pattern of joint lines caused by the formwork and by the

construction joints to ensure continuity of horizontal and vertical lines.

4 Masonry nails or similar items shall not be used to fix formwork of the like to permanent

concrete works.

9.4.2 Trial Panels

1 The trial panels shall comprise surfaces that have unformed surfaces and formed surfaces

F1, F2 and F3.

2 The concrete cast from the job mock-up shall be used to assess the acceptability of the

Contractor’s workmanship for finishing.

3 If the finishing is deemed unacceptable by the Engineer, the Contractor shall prepare a

further mock-up with a particular class of finish.

4 The job mock-ups shall be retained during the course of the works to allow comparative

inspection, with production concreting and finishing and for the purpose of colour comparison

to ensure colour consistency.

9.4.3 Formwork Face in Contact with Concrete

1 Faces of formwork in contact with concrete shall be free from adhering foreign matter,

projecting nails and the like, splits or other defects, and all formwork shall be clean and free

from standing water, dirt, shavings, chippings or other deleterious matter.

2 Joints between forms and tie holes shall be watertight to prevent the escape of mortar or the

formation of fins or other blemishes on the face of the concrete.

3 The Contractor shall verify lines, levels and measurement before proceeding with formwork

erection.

4 The formwork surface shall be made clean and free from any foreign and deleterious matter,

prior to start the concrete pour.

5 In hot weather, the surface of the formwork shall be sprayed with water in order to lower the

temperature, prior to start the pour.

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9.4.4 Sloping Surfaces

1 Formwork shall be provided for the top surfaces of sloping work where the slope exceeds

15 from the horizontal (except where any such top surface is specified as a spaded finish).

2 The formwork shall be anchored to enable the concrete to be properly compacted and to

prevent flotation.

3 Care shall be taken to prevent air being trapped under the sloping formwork.

9.4.5 Temporary Openings

1 The Contractor shall provide temporary openings for inspection of the inside of the formwork

and for the removal of water used for washing down. The openings shall be formed as to be

easily closed before placing concrete.

2 Temporary opening shall be avoided in the case of fair faced concrete.

9.4.6 Form Windows

1 The Contractor shall provide windows in forms wherever directed by the Engineer or

necessary for access for concrete placement and vibration.

2 The windows shall be of a size adequate for tremies and vibrators spaced at maximum 1.8 m

centres horizontally.

3 Any windows shall be tightly closed and sealed before proceeding to place concrete at a

higher level.

9.4.7 Co-ordination

1 The Contractor shall ensure that the work of other trades in forming and setting openings,

slots recesses, chases, sleeves, bolts, anchors and other inserts is fully co-ordinated.

9.4.8 Conduits

1 Conduits or pipes shall be located so as not to reduce the strength of the construction.

2 In no case shall pipes other than conduits be placed in a slab 125 mm or less in thickness.

3 Conduits embedded in a concrete slab shall not have an outside diameter greater than

one-third the thickness of the slab nor be placed below the bottom reinforcing steel or over

the top reinforcing steel.

4 Conduits may be embedded in walls provided they are not larger in outside diameter than

one-third the thickness of the wall, are not spaced closer than three diameters on centre, and

do not impair the strength of the structure.

5 Embedded pipes and conduits shall be supported independently from reinforcing steel in a

manner to prevent metallic contact and thereby prevent electrolytic deterioration.

6 Pipes and conduits where embedded shall be placed as nearly as possible to the centre line

of the concrete section.

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7 Conduits, piping, and other wall penetrations or reinforcements shall be subject to the

Engineer’s review and approval.

8 Conduits shall be fixed properly to avoid any displacement during concreting and prevent

coming in contact with the forms.

9.4.9 Ties and Bolts

1 The position of ties passing through concrete shall be subject to the approval of the Engineer.

2 Ties, bolts or other devices shall not be built into the concrete for the purpose of supporting

formwork without the prior approval of the Engineer. The whole or part of any such supports

shall be capable of removal so that no part remaining embedded in the concrete shall be

nearer to the surface than the cover required for reinforcement.

9.4.10 Chamfers

1 Chamfer moulding strips shall be positioned on the exposed corners of columns and beams.

9.4.11 Cambers

1 If required, cambers shall be as shown on the Drawings.

2 The depth of beams at all points in the span, where cambers are used, shall be as shown on

the Drawings.

3 Allowance shall be made for compression and settlement of the formwork on line and level.

9.4.12 Exterior Angles

1 All exterior angles to concrete exposed to view in the completed structure shall be cast to the

true angles evenly throughout the length.

2 Care shall be taken to ensure that no waviness occurs along the angle and that no spalling

occurs to the concrete on removal of the formwork.

9.4.13 Surface Retarders

1 Surface retarders shall not be used on any formwork surface in contact with concrete unless

expressly authorised by the Engineer.

9.4.14 Detection of Movement During Concrete Placement

1 Devices of telltale type shall be installed on supported forms and elsewhere as required to

detect formwork movements and deflection during concrete placement.

2 Where required slab and beam cambers shall be checked and correctly maintained as

concrete loads are applied on forms.

3 Workmen shall be assigned to check forms during concrete placement and to promptly seal

all mortar leaks.

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4 The forms shall be checked during concreting in order to identify any displacement and

provide corrective actions immediately.

9.4.15 Building in Pipes

1 Pipes and pipe specials through concrete walls and floors shall as far as possible be

positioned and built in during construction. They shall be located exactly in the positions

shown on the Drawings and shall be true to line and level.

2 The Contractor shall take particular care to ensure that fully compacted concrete is in contact

with the pipe at all points.

3 Where it is not practicable to cast pipes and specials in the concrete, boxholes shall be

formed in the shuttering.

4 The box shall have six or eight sides, depending on the pipe diameter, and shall be no larger

in size than will give adequate clearance for the subsequent positioning and grouting in of the

pipe. The sides of the boxhole shall be provided with a tapered central annular recess to

provide a positive key. The boxhole shall be provided with a grout hole and, at the top of the

central annular recess, a vent hole. The boxhole shall be stripped with the main shuttering

and the concrete surface thoroughly cleaned and roughened.

5 When the pipe is later fixed, the remaining hole shall be reshuttered and filled with non-shrink

epoxy grout or non-shrink concrete. In the case of water retaining structures, the Contractor

shall ensure that the measures adopted shall provide a finished joint which is resistant

against and free from leakage.

9.4.16 Working Platform

1 Safe working platform shall be provided according to Section 11 (Health and Safety).

9.4.17 Safe Access

1 Safe access shall be provided for the workers, inspectors, and other users according to

Section 11 (Health and Safety).

9.4.18 Kickers

1 Kickers shall be provided for walls and columns

2 The kickers shall be water tight in order to prevent any grout loss.

9.4.19 Cover Spacers

1 Cover spacers shall be used in order to maintain the required cover between the formwork

and reinforcement.

9.4.20 Water Bars

1 In the case of watertight constructions water bars or equivalent, as approved by the Engineer,

shall be used at joints.

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9.5 REMOVAL OF FORMWORK

9.5.1 General

1 The Engineer shall be notified in writing before the removal of any formwork.

2 The Contractor, under no circumstances, shall strike the formwork until the concrete has

attained adequate strength to resist damage, in particular to arises and features.

3 Concrete shall be thoroughly wetted as soon as the forms are first loosened and shall be kept

wet during the removal operations and until the curing media is applied.

4 A potable water supply with hoses having fine fog spray attachments shall be ready at each

removal location before operations are commenced.

5 The forms after removal shall be cleaned and prepared for subsequent use.

9.5.2 Stripping of Formwork

1 The period of time elapsing between the placing of the concrete and the striking of the

formwork shall be approved by the Engineer after consideration of the loads likely to be

imposed on the concrete and shall in any case be not less than the periods shown in

Table 9.1

2 Stripping of the formwork within the time limits listed above does not relieve the Contractor

from successfully crushing test cubes and achieving the specified compressive strength

results.

3 Notwithstanding the foregoing the Contractor shall be held responsible for any damage

arising from removal of formwork before the structure is capable of carrying its own weight

and any incidental loading.

4 Where finished surfaces have re-entrant angles, the formwork shall be removed as early as

possible, within the time limits set above, to avoid shrinkage cracks.

5 The formwork shall be carefully stripped to avoid sudden shocks from the removal of

wedges, or vibration which might cause damage to the concrete.

6 Reshoring to beams and slabs shall be placed immediately after stripping formwork.

Table 9.1

Stripping Times of Formworks

Type Of Formwork Minimum Period Before

Stripping (Times Are From Concrete Placement)

Beam sides, walls and column 1 d

Soffits of slabs (props left under) 4 d

Soffits of beams, joists and girders (props left under) 10 d

Props to slabs 11 d

Props to beams 15 d

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9.5.3 Holes to be Filled

1 Holes formed in concrete surfaces by formwork supports or the like shall be filled neatly with

non-shrink grout.

2 The Contractor shall clean and scarify any hole that is to be filled with non-shrink grout.

9.5.4 Repair to Damaged Concrete Surfaces

1 Where the concrete surface has been damaged, the Contractor shall break out any loose,

broken or cracked concrete or aggregate.

2 The concrete surrounding the hole shall be then be thoroughly soaked after which the

surface shall be dried so as to leave a small amount of free water on the surface. The

surface shall then be dusted with ordinary Portland cement by means of a small dry brush

until the whole surface that will come into contact with the dry-pack mortar has been covered

and darkened by absorption of the free water by the cement. Any dry cement in the hole shall

be removed

3 Dry-pack material shall then be placed and packed in layers having a compacted thickness in

accordance with the manufacturer’s instructions. Compaction shall be carried out by the use

of a hardwood stick and a hammer and shall extend over the full area of the layer, particular

care being taken to compact the dry-pack against the side of the hole. After compaction the

surface of each layer shall be scratched before further loose material is added

4 The hole shall not be over-filled and the surface shall be finished by layering a hardwood

block against the dry-pack fill and striking the block several times. Steel finishing tools shall

not be used and water shall not be added to facilitate finishing.

5 The surface of the concrete shall be rubbed down smooth with carborundum and water in an

approved manner within three days of removing the formwork. Holes left after removal of

such supports shall be neatly filled with non-shrink grout of a suitable consistency and

matching colour.

9.6 DELIVERY AND STORAGE

9.6.1 Delivery

1 The delivery of formwork materials shall be done in such a manner that damage can be

prevented.

9.6.2 Storage

1 Formwork should be stored, after cleaning and preparing for reuse if used before, in such a

manner that access to all different materials is available.

2 Materials which can be affected by weathering shall be stored in appropriate buildings or

under cover.

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9.7 TOLERANCES

1 The concrete work shall be constructed to an accuracy which shall permit the proper

assembly of components and installations and shall be compatible with the finish. The

accuracy of the work shall be within the tolerances shown on the Drawings or specified

elsewhere and, in the absence of any other requirements, shall comply with the following:

All laying out dimensions 5 mm

Sections of concrete members 5 mm

Surface of foundations against ground 10 mm

Top surfaces of foundations, bases and piers 20 mm

Surface level of floor slabs (5m straight edge) 5 mm

Surface level of floor slabs to datum 10 mm

Plumb of columns and walls in storey height 5 mm

Plumb of columns and walls in full building height (for each storey) above the top of foundation:

20m ≥ building height 20 mm

150m ≥ building height ≥ 20 m (1/1000) of height

building height ≥ 150 m 150 mm

Inside faces of elevator shafts in storey height 5 mm

Inside faces of elevator shafts in full building height (for each storey) above the top of foundation:

20m ≥ building height 10 mm

150m ≥ building height ≥ 20 m (0.5/1000) of height

building height ≥ 150 m 75 mm

9.8 EARLY LOADING

1 The Contractor should note that the loading from the falsework and wet concrete, during the

construction of a floor, will not exceed the permissible loading on the floor immediately below.

Consequently two of the floors immediately below the one being constructed will need to be

used, to share the loading.

2 While propping through two floors, the Contractor shall ensure, that the props beneath the

floor last constructed are released over its full extent as soon as the concrete has achieved

sufficient strength to support itself plus any superimposed loading, but not sooner than the

periods given in Table 9.1. The props shall then be re-tightened so that these may be used

to share the construction loading from the floor above.

3 Not withstanding the requirements of this Section for the removal times for formwork, the

following provisions shall apply to early loading of concrete.

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4 Concrete shall at no time be subject to loading including its own weight which will induce a

compressive stress in excess of 0.33 of the actual compressive strength of the concrete at

the time of loading or 0.33 of the specified 28 d characteristic strength whichever is the lower.

For the purpose of this clause the assessment of the strength of the concrete and the stress

produced by the loads shall be subject to the agreement of the Engineer.

5 If, due to his method of construction, the Contractor wishes to place an imposed load on the

structure, he shall arrange for additional cubes to be cast at the point of the structure to be

loaded and these cubes will be crushed to monitor the compressive strength in accordance

with BS EN 12390-3 Compressive strength of test specimens. The Contractor shall submit

calculations showing the stresses induced by any proposed temporary loads to be placed on

the structure.

6 No superstructure load shall be placed upon finished piers or abutments until the Engineer

has given his approval in writing and in no case shall any load be placed until the curing

period is complete.

7 Deck slabs of bridges shall only be opened to traffic or construction equipment and plant

when authorised by the Engineer and in no case until the curing period is complete.

END OF PART

QCS

QCS 2014 Section 05: Concrete Page 1 Part 10: Curing

10 CURING .................................................................................................................. 2

10.1 GENERAL ............................................................................................................... 2

10.1.1 Scope 2

10.1.2 References 2

10.1.3 Submittals 2

10.1.4 Quality Assurance 2

10.1.5 Storage 2

10.2 CURING .................................................................................................................. 2

10.2.1 General 2

10.2.2 Water for Curing 3

10.2.3 General Requirements 3

10.2.4 Curing of Formed Surfaces 4

10.2.5 Curing of Unformed Surfaces 4

10.2.6 Moisture Curing 4

10.2.7 Moisture Retaining Cover Curing 4

10.2.8 Liquid Membrane Curing 5

10.2.9 Steam Curing 5

10.2.10 Pavements and other slab on ground 5

10.2.11 Buildings, bridges, and other structures 5

10.2.12 Mass concrete 6

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10 CURING

10.1 GENERAL

10.1.1 Scope

1 This part covers the requirements for the curing of concrete.


This Section

Part 1, ............ General

Part 4, ............ Water

Part 6, ............ Property Requirements

Part 15, ........... Hot Weather Concreting

Part 16, ........... Miscellaneous.

10.1.2 References

AASHTO M 148.74, ... Liquid Membrane Curing

ACI 308 ..................... Guide to Concrete Curing

ASTM C 309, .............. Specification for Liquid Membrane-forming Compounds for Curing

Concrete

BS 7542, ..................... Method of test for curing compounds for concrete.

ISO 9001: 2008 Quality management systems -- Requirements

10.1.3 Submittals

1 The Contractor shall submit to the Engineer the proposed method of curing for approval.


1 The Contractor shall submit to the Engineer for approval the details of proposed curing

media, if any. Details shall include chemical tests for the product in accordance with

BS 7542 and details of quality assurance procedures, including ISO 9001 certificates if held.

10.1.5 Storage

1 Chemical curing compounds shall be stored in accordance with manufacturer's

recommendations.

10.2 CURING

10.2.1 General

1 The Contractor shall ensure that curing is provided for 24 hours per day including holidays

and that all related necessary plant and labour resources are also available.

2 Special attention shall be given to the curing of vertical and overhanging surfaces to ensure

satisfactory curing.

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3 The Contractor shall adopt curing measures that preclude the possibility of thermal shock to

the concrete during curing. This may be achieved by ensuring that the temperature of the

water used for curing does not differ from that of the concrete by more than 15 C.

4 Curing shall continue for at least 7 days and until it attains an in-place compressive strength

of the concrete of at least 70% of the specified compressive or flexural strength, whichever

period is longer. Curing shall not stop unless otherwise approved by the Engineer.

5 When low W/cm is used, the concrete shall be preferably cured by water.

10.2.2 Water for Curing

1 Water used for any curing purposes shall conform to the requirements of Part 4 of this

Section.

10.2.3 General Requirements

1 Freshly placed concrete shall be protected from sun, wind, rain, exposure and excessive

drying out.

2 All concrete shall be cured for a period of time required to obtain the full specified strength,

but not less than seven consecutive days. The method of curing shall be by water for the first

seven days and by water or membrane until the concrete has reached the full specified

strength.

3 For mixtures with a low to zero bleeding rate, or in the case of aggressively evaporative

environments, or both, the curing shall start at early anytime between placement and final

finishing of the concrete. The curing shall be by reducing the moisture loss from surface

using fogging systems and the use of evaporation reducers such as monomolecular water

curing compound.

4 Exposed surfaces shall be protected from air blown contamination until 28 d after the

concrete is placed.

5 The method of curing shall ensure that sufficient moisture is present to complete the

hydration of the cement, and shall be to the approval of the Engineer. The method of curing

shall not:

(a) disfigure permanently exposed surfaces

(b) affect bonding of subsequent coatings

(c) increase the temperature of the concrete.

6 During the curing period, exposed concrete surface shall be protected from the direct rays of

the sun.

7 When liquid membrane is used to cure the concrete, it shall not be applied if bleeding water

is present on the surface of the concrete.

8 The applied film of the liquid membrane shall be continuous and protected from rain and any

damages for at least 14 days.

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10.2.4 Curing of Formed Surfaces

1 Formed surfaces, including the underside of beams, girders, supported slabs and the like, by

moist curing with the forms in place for the full curing period, or until the forms are removed.

2 When the forms are stripped, curing shall continue by any approved method.

3 When liquid membrane curing is used, it shall be applied immediately after de-shuttering. In

such cases the concrete surface shall be prepared prior to the application of the membrane

as recommended by the manufacturer.

4 Water curing is not required when liquid membrane is used.

10.2.5 Curing of Unformed Surfaces

1 Unformed surfaces shall be protected as soon as possible after the concrete has been

placed by polythene sheeting. When sufficiently hard, hessian or other absorbent material

shall be placed on the concrete surface and shall be kept wet for the required period. The

hessian shall be overlaid with a sheet of 1000 gauge polythene to assist in the retention of

water. Alternatively a curing method approved by the Engineer may be used.

2 Once the concrete is sufficiently hard, the top exposed surface of walls, columns and beams

shall be water cured and covered with wet hessian for the required curing period.

10.2.6 Moisture Curing

1 Moisture curing shall be performed by :

(a) covering the surface of the concrete with water and keeping it continuously wet

(b) continuous use of fine fog water sprays

(c) covering the surface with a saturated absorptive cover and keeping it continuously

wet.

(d) Burlap, cotton mats, and other absorbent materials can be used to hold water on

horizontal or vertical surfaces.

(e) Wet straw or hay can be used for wet-curing small areas, but there is the danger that

wind might displace it unless it is held down with screen wire, burlap, or other means

2 Where method (a) is employed, the bunds used shall not be made from fill from excavations

or any other areas where there is the possibility of chloride contamination.

10.2.7 Moisture Retaining Cover Curing

1 The concrete surface shall be covered with a suitable absorptive covering, such as wet

hessian.

2 The absorptive covering shall be overlaid with a 1000 gauge polythene sheet.

3 The cover shall be in the widest practical widths and shall have 100 mm side and end laps.

4 Any penetrations or tear in the covering shall be shall be repaired with the same material and

waterproof tape.

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10.2.8 Liquid Membrane Curing

1 Liquid membrane curing shall be in accordance with the requirements of BS 7542, ASTM

C 309 or C1315 when tested at the rate of coverage use on the job.

2 ASTM C 156 shall be used as a test method to evaluate water-retention capability of liquid

membrane forming compounds. ASTM C 1151 provides an alternative laboratory test for

determining the efficiency of liquid membrane-forming compounds.

3 Membrane forming curing compounds shall be applied in accordance with the manufacturer's

recommendations immediately after any water sheen which may develop after finishing has

disappeared from the surface and within 2 h of stripping formwork on formed surfaces.

4 Membrane forming curing compounds shall not be used on surfaces against which additional

concrete or other material is to be bonded unless:

(a) it is proven that the curing compound will not prevent bond, or

(b) positive measures are taken to remove it completely from those areas which are to

receive bonded applications

(c) on fair faced concrete surfaces.

10.2.9 Steam Curing

1 An enclosure shall be formed around the concrete using tarpaulin or other suitable means.

2 Application of steam shall not be commenced until at least 2 h after final placement of

concrete.

3 Steam shall be applied at a temperature between 65 C and 80 C.

4 Excessive rates of heating and cooling shall be prevented during steam curing and

temperatures in the enclosure shall not be allowed to increase or decrease by more than

22 C per hour.

5 The maximum steam temperature shall be maintained in the enclosure until concrete has

reached its specified strength.

10.2.10 Pavements and other slab on ground

1 Curing shall ensure that no plastic shrinkage crack will occur, this can be done by protective

measures such as sun shields, wind breaks, evaporation reducers, or fog spraying should be

initiated immediately to reduce evaporation.

2 Mats used for curing can either be left in place and kept saturated for completion of the

curing, or can be subsequently replaced by a liquid membrane-forming curing compound,

plastic sheeting, reinforced paper, straw, or water

10.2.11 Buildings, bridges, and other structures

1 Additional curing shall be provided after the removal of forms

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2 After the concrete has hardened and while the forms are still in place on vertical and other

formed surfaces, form ties may be loosened when damage to the concrete will not occur and

water applied to run down on the inside of the form to keep the concrete wet.

3 Care shall be taken to prevent thermal shock and cracks when using water that is

significantly cooler than the concrete surface. Curing water should not be more than about

11oC cooler than the concrete.

4 Immediately following form removal, the surfaces shall be kept continuously wet by a water

spray or water-saturated fabric or until the membrane-forming curing compound is applied.

Curing

10.2.12 Mass concrete

1 Mass concrete is often cured with water for the additional cooling benefit in warm weather;

however, this can be counterproductive when the temperature gradient between the warmer

interior and the cooler surface generates stress in the concrete.

2 Horizontal or sloping unformed surfaces of mass concrete can be maintained continuously

wet by water spraying, wet sand, or water saturated fabrics.

3 For vertical and other formed surfaces, after the concrete has hardened and the forms are

still in place, the form ties may be loosened and water supplied to run down the inside of the

form to keep the concrete wet

4 Care shall be taken to prevent thermal shock and cracks when using water that is

significantly cooler than the concrete surface. Curing water should not be more than about

11oC cooler than the concrete.

5 Curing shall start as soon as the concrete has hardened sufficiently to prevent surface

damage.

6 For unreinforced massive sections not containing ground granulated blast-furnace slag or

pozzolan, curing shall be continued for not less than 2 weeks. Where ground granulated

blast-furnace slag or pozzolan is included in the concrete, the minimum time for curing shall

be not less than 3 weeks.

7 For reinforced mass concrete, curing shall be continuous for a minimum of 7 days or until

70% of the specified compressive strength is obtained, if strength is the key concrete

performance criterion. For construction joints, curing shall be continued until resumption of

concrete placement or until the required curing period is completed.

8 Curing shall not stop until favourable differential temperature is attained and at the approval

of the Engineer.

9 For mass concrete, thermocouples shall be used to monitor the temperature differential of

the concrete.

END OF PART

QCS

QCS 2014 Section 05: Concrete Page 1 Part 11: Reinforcement

11 REINFORCEMENT ................................................................................................. 2

11.1 GENERAL ............................................................................................................... 2

11.1.1 Scope 2

11.1.2 References 2

11.1.3 Submittals 3


11.1.5 Delivery Storage and Handling 3

11.2 REINFORCING MATERIALS .................................................................................. 4

11.2.1 Reinforcing Bars 4

11.2.2 Welded Steel Wire Fabric 4

11.2.3 Tie Wire 5

11.3 INSPECTION, SAMPLING AND TESTING.............................................................. 5

11.3.2 Sampling 5

11.3.3 Testing 6

11.4 CUTTING AND BENDING OF REINFORCEMENT ................................................. 6

11.5 FIXING OF REINFORCEMENT ............................................................................... 6

11.5.1 General 6

11.5.2 Welding 7

11.5.3 Mechanical Splices 8

11.5.4 Bundling and Splicing of Bundled Bars 8

11.5.5 Examination 8

11.5.6 Electrolytic Action 8

11.5.7 Cover 8

11.5.8 Reinforcement 8

11.5.9 Forms and Linings 9

11.5.10 Tanking 9

11.5.11 Adjustment and Cleaning 9

11.6 PROTECTIVE COATINGS TO REINFORCEMENT ................................................ 9

11.6.2 Epoxy Coated Reinforcing Bars 9

11.6.3 Handling of Epoxy Coated Reinforcement 11

11.6.4 Testing of Epoxy Coated Reinforcement 11

QCS


11 REINFORCEMENT

11.1 GENERAL

11.1.1 Scope

1 This Part includes tension, compression, and temperature reinforcing steel, including welded

wire fabric, and epoxy coated reinforcing. The work includes furnishing, fabrication, and

placement of reinforcement for cast-in-place concrete, including bars, welded wire fabric,

ties, and supports.


This Section


Part 17 ............. Structural Precast Concrete

11.1.2 References

ASTM A416/A416M .... Standard Specification for Steel Strand, Uncoated Seven-Wire for

Prestressed Concrete

ASTM 615/615M ........ Standard Specification for Deformed and Plain Carbon-Steel Bars for

Concrete Reinforcement

ASTM A706, ............... Specification for Low-allow Steel Deformed Bars for Concrete

Reinforcement

ASTM A881/A881M ... Standard Specification for Steel Wire, Deformed, Stress-Relieved or

Low-Relaxation for Prestressed Concrete Railroad Ties

ASTM A882/A882M- .. Standard Specification for Filled Epoxy-Coated Seven-Wire

Prestressing Steel Strand

ASTM A955/A955M-14 Standard Specification for Deformed and Plain Stainless-Steel Bars

for Concrete Reinforcement ASTM A1022/A1022M-14a Standard Specification for Deformed and Plain Stainless Steel

Wire and Welded Wire for Concrete Reinforcement

ASTM A1035/ A1035M Deformed and Plain, Low-carbon, -Chromium, -Steel Bars for

Concrete Reinforcement:

BS 4449 : 2005 ........... Specification for Carbon steel bars for the reinforcement of concrete

BS 4482: 2005, ........... Specification for Cold reduced steel wire for the reinforcement of

concrete

BS 4483: 2005 ............ Steel fabric for the reinforcement of concrete

BS 5896, ..................... Specification for high tensile steel wire and strand for the prestressing

of concrete.

BS 8666, ..................... Specification for scheduling, dimensioning, bending and cutting of

steel reinforcement for concrete

EN 1011, .................... Welding. Recommendation for welding of metallic materials

EN 1992-1-1 Eurocode 2: Design of concrete structures. General rules and rules for buildings

ISO 14654, ................. Epoxy- coated steel for the reinforcement of concrete

ISO 14656, ................. Epoxy powder and sealing material for the coating of steel for the

reinforcement of concrete

http://www.astm.org/Standards/A416.htm










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ISO 3766 ................... Construction drawings -- Simplified representation of concrete

reinforcement

ISO 9000, .................. Quality management systems. Fundamentals and vocabulary

QS ISO 6935-1:2007, . Steel for the reinforcement of concrete -Part 1: Plain bars

QS ISO 6935-2:2007 .. Steel for the reinforcement of concrete Part 2: Ribbed bars

QS ISO 6935-3:2007 .. Steel for the reinforcement of concrete Part 3: Welded fabric

11.1.3 Submittals

1 Product data including the manufacturer’s specification and installation instructions for

proprietary materials and reinforcement accessories shall be provided.

2 The Contractor shall submit the manufacturer’s records of chemical and physical properties

of each batch of billet steel bars and a certificate that the respective material furnished meets

the requirements for the steel reinforcement specified. The manufacturer’s records shall

include certificates of mill as well as analysis, tensile and bend tests of the reinforcement.

3 Three copies of the steel test report shall be furnished with each consignment of steel

reinforcement. The steel shall be tagged and cross-referenced with mill certificates.


1 The Contractor shall submit to the Engineer for source approval details of the proposed

source of supply of the reinforcement. Details shall include chemical and physical tests for

the past six months production and any independent test results for this period. Details of

quality assurance procedures, including ISO 9000 certificate if held, shall also be given.

2 The Contractor shall furnish the Engineer with a certificate of compliance for each shipment

of epoxy coated bars. The certificate of compliance shall state that representative samples of

the epoxy coated bars have been tested and that the test results comply with the

requirements herein specified. Test results shall be retained by the Contractor for seven

years. A complete set of test results shall also be handed to the client at the completion of

reinforcement works, and shall be made available to the Engineer upon request.

11.1.5 Delivery Storage and Handling

1 On delivery, bars in each lot shall be legibly tagged by the manufacturer. The tag shall show

the manufacturer’s test number and lot number and other applicable data that will identify the

material with the certificate issued for that lot of steel. The fabricator shall furnish three

copies of a certification which shows the batch number or numbers from which each size of

bar in the shipment was fabricated.

2 Storage of reinforcement shall be on suitable structures a minimum of 450 mm above the

ground surface to prevent damage and accumulation of dirt, rust and other deleterious

matter. Storage facilities shall be such as to permit easy access for inspection and

identification. Reinforcement bundles shall be clearly tagged with bar schedule and bar mark

reference.

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3 The reinforcement shall not be roughly handled, dropped from a height, or subjected to shock

loading or mechanical damage. Steel reinforcing bars shall be kept clean and shall be free

from pitting, loose rust, mill scale, oil, grease, earth, paint, or any other material which may

impair the bond between the concrete and the reinforcement. The reinforcement shall be

covered to ensure protection from wind blown dust, condensation and other deleterious

materials.

11.2 REINFORCING MATERIALS

11.2.1 Reinforcing Bars

1 Reinforcement shall be from an acceptable source. All steel reinforcement bars shall comply

with the requirements of:

(i) QS ISO 6935 with minimum grade of B500 MPa or

(ii) BS 4449 with minimum grades of B500 MPa ; or..

(iii) ASTM A615 / A615M with minimum grade of 75 [520MPa]; or

(iv) Deformed and Plain, Low-carbon-Chromium-Steel Bars for Concrete

Reinforcement: ASTM A1035/ A1035M

(v) ASTM A1022/A1022M-14a Standard Specification for Deformed and Plain

Stainless Steel Wire and Welded Wire for Concrete Reinforcement

(vi) ASTM A955/A955M-14 Standard Specification for Deformed and Plain

Stainless-Steel Bars for Concrete Reinforcement

(vii) Other types of reinforcement, as approved by Qatar Standards

2 As per project design, other steel grades of less than B500MPa may be used only for stirrups

and secondary reinforcement of diameter of 10mm or less.

3 If the steel has excessive surface rust, dust or other deleterious material then the steel shall

be sand blasted. Sand for blasting shall not contain materials deleterious to the durability of

the reinforcement or concrete. Dune sand shall not be used for the sandblasting of

reinforcement.

4 For extreme exposure class X5; protection measures such as epoxy coated bars; Low-

carbon-chromium-steel bars; or Stainless Steel may be considered.

11.2.2 Welded Steel Wire Fabric

1 Steel fabric reinforcement shall comply with the requirements of QS ISO 6935-3 or BS 4483

and shall be delivered to Site in flat mats.

2 Welded intersections shall not be spaced more than:

(a) 300 mm for plain round bars

(b) 400 mm apart for deformed high yield bars in direction of calculated stress except

when used as stirrups.





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11.2.3 Tie Wire

1 Tie wire shall conform to the requirements of BS 4482.

2 1.6 mm black annealed mild steel shall be used for tie wire.

3 No wires smaller than size D-4 shall be used.

11.3 INSPECTION, SAMPLING AND TESTING

1 Inspection of reinforcing steel and the installation thereof will be conducted by the Engineer.

2 The Contractor shall give 24 hour notice to the Engineer before closing forms or placing

concrete.

3 The Engineer may instruct the Contractor to break out and remove completely all sections of

the work already constructed under any of the following circumstances:

(a) reinforcing steel sample under test fails to meet the specification requirements at any

time

(b) the Engineer considers that samples which were presented to him for test were not

truly representative

(c) a previously rejected reinforcing steel has been used in the Works.

11.3.2 Sampling

1 Representative samples of all reinforcing steel proposed for use in the Works must be

submitted by the Contractor, before work is commenced, to the Engineer for his written

approval.

2 Manufacturer's certificates stating clearly for each sample:

(a) place of manufacture

(b) expected date and size of deliveries to site

(c) all relevant details of composition, manufacture, strengths and other quality of the

steel.

3 The Engineer reserves the right to sample and inspect reinforcement steel upon its arrival at

the work site.

4 Frequency of sampling and the method of quality control shall be in accordance with steel

bars manufactured standard QS ISO 6935 or BS 4449 .

5 Where epoxy coated steel is used, a sample of the coating material shall be supplied with

each batch in an airtight container and identified by the batch number.

6 Allow 14 days for Engineer’s review of samples.

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11.3.3 Testing

1 Tests shall be carried out when directed by the Engineer.

2 Tests shall be carried out in accordance with QS ISO 6935 or BS 4449.

3 The following information shall be provided with each delivery of reinforcement:

(a) elastic limit

(b) ultimate strength

(c) stress/strain curve

(d) cross-sectional area

(e) deformation/bond characteristics of deformed bars.

4 The Contractor shall allow for dimensions and weight measurements, tensile, bend and/ or

rebend tests at own cost, for each size of bar to be used in the concrete construction.

5 Test results for each bar size shall be submitted to the Engineer three weeks before concrete

work commences on Site.

6 Full testing shall be required if the source of supply of reinforcement changes, in which case

the cost of such extra testing will be borne by the Contractor.

7 When any test results do not conform to the relevant standard the reinforcement steel shall

be removed from the Site and all costs resulting therefrom shall be borne by the Contractor.

11.4 CUTTING AND BENDING OF REINFORCEMENT

1 Cutting and bending of reinforcement shall be in accordance with ISO 3766 or BS 8666 and

shall be done without the application of heat. Bends shall have a substantially constant

curvature. For epoxy coated steel the provisions of Clause 11.6.1 of this Part shall apply

2 Steel bars manufactured according to the approved ASTM standards shall be bent according

to the same standard.

3 Reinforcement shall not be straightened or rebent without the approval of the Engineer. If

permission is given to bend projecting reinforcement care shall be taken not to damage the

concrete and to ensure that the radius is not less than the minimum specified in ISO 3766 or

BS 8666.

11.5 FIXING OF REINFORCEMENT

11.5.1 General

1 All reinforcement shall be securely and accurately fixed in positions shown on the Drawings

to ensure that the reinforcement steel framework as a whole shall retain its shape. The

framework shall be supported to retain its correct position in the forms during the process of

placing and consolidating the concrete.

2 The ends of all tying wires shall be turned into the main body of the concrete and not allowed

to project towards the surface.

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3 No part of the reinforcement shall be used to support access ways, working platform or for

the conducting of an electric current.

4 The Contractor’s specific attention is drawn to the following general requirements:

(a) lapped joints shall be as indicated on the Drawings and/or in accordance with the

requirements of EN 1992-1-1 or BS 8666

(b) hooks shall be semicircular with a straight length of at least:

(i) four bar diameters for mild steel

(ii) six bar diameters for high yield steel.

11.5.2 Welding

1 Welding shall not be used unless authorised by the Engineer and recommended by the

reinforcement manufacturer.

2 Where welding is approved it shall be executed under controlled conditions in a factory or

workshop.

3 Welding shall not take place on site without the approval of the Engineer and unless suitable

safeguards and techniques are employed and the types of steel employed have the required

welding properties.

4 Welding if approved, may be used for:

(a) fixing crossing or lapping reinforcement in position

(b) fixing bars to other steel members

(c) structural welds involving transfer of loads between reinforcement or between bars

and other steel members.

5 The length of run deposited in a single pass shall not exceed five times the bar diameter. If a

longer welded length is required, the weld shall be divided into sections with the space

between runs made not less than five times the bar diameter.

6 Butt welds shall be formed by flash butt welding or metal-arc welding. Other methods may be

approved, subject to their satisfactory performance in trial joints.

7 Metal-arc welding or electrical resistance welding may be used for fixing suitable steels or for

lapped joints.

8 Flash butt welding shall be executed with the correct combination of flashing, heating,

upsetting and annealing, using only machines which automatically control this cycle of

operations.

9 Metal-arc welding shall comply with EN 1011 and the recommendations of the reinforcement

manufacturer.

10 Welded joints shall not be made at bends in the reinforcement. Joints in parallel bars of

principle reinforcement shall be staggered, unless otherwise approved. The distance

between staggered joints shall be not less than the end anchorage length joints.

11 Weldable reinforcement where shown on the Drawings shall conform to ASTM A706.

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11.5.3 Mechanical Splices

1 Mechanical splices shall comply with EN 1992-1-1 or BS 8666, and shall be used as and

where indicated on the Drawings.

2 Details of mechanical splices shall be submitted to the Engineer for approval.

11.5.4 Bundling and Splicing of Bundled Bars

1 Bundling and splicing of bundled bars shall be in accordance with EN 1992-1-1 or BS 8666.

2 Splicing, except where indicated on the Drawings or approved shop drawings, will not be

permitted without the approval of the Engineer.

11.5.5 Examination

1 The Contractor shall notify the Engineer at least 24 hours before commencing the fixing of

reinforcement in order to facilitate the inspection of formwork.

2 The Contractor shall ensure that areas to receive reinforcement are cleaned before fixing.

11.5.6 Electrolytic Action

1 Reinforcement shall not be fixed or placed in contact with non-ferrous metals.

11.5.7 Cover

1 Correct concrete cover to reinforcement shall be maintained with the aid of approved spacer

pieces.

2 The cover shall not be less than given in Section 5 Part 6.

3 Spacers, chairs and other supports shall be provided as necessary to maintain the

reinforcement in its correct position.

4 In a member where the nominal cover is dimensioned to the links, spacers between the links

and formwork shall be the same dimension as the nominal cover.

5 Spacer bars shall be of the same diameter as longitudinal bars, but not less than 25 mm in

diameter, and shall be fixed between two layers at 1.5 m centres except where bundled bars

are detailed.

6 Spacers, chairs and other supports shall be made of concrete, plastic or other material to the

approval of the Engineer. Where supports are made of concrete they shall have at least the

same cube strength as the concrete in the host member.

11.5.8 Reinforcement

1 Placing of all reinforcement steel bars will be checked by the Engineer and in no case is

concrete to be placed around any reinforcement steel that has not been approved by the

Engineer. Insertion of bars into or the removal of bars from concrete already placed will not

be permitted.

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2 Reinforcement steel temporarily left projecting from the concrete at the joints shall not be

bent without the prior approval of the Engineer.

11.5.9 Forms and Linings

1 Damage to forms and linings shall be avoided.

11.5.10 Tanking

1 Reinforcement shall not be fixed until completion of placing tanking (membrane) protection.

11.5.11 Adjustment and Cleaning

1 Check position of reinforcement before and during placing concrete:

(a) pay particular attention to the position of top reinforcement in cantilever sections

(b) ensure that reinforcement is clean and free from corrosive pitting, loose rust, loose mill

scale, oil and other substances which may adversely affect reinforcement, concrete, or

the bond between the two.

2 Protect projecting reinforcement from the weather where rust staining of exposed concrete

surfaces may occur.

3 At the time of concreting, all reinforcement steel shall have been thoroughly cleaned and

freed from all mud, oil or any other coatings that might destroy or reduce the bond:

(a) clean all set or partially set concrete which may have been deposited thereon during

the placing of a previous lift of concrete

(b) all uncoated rust bars shall be again sand blasted and pressure washed.

4 Immediately before concrete placing the reinforcing steel shall be washed thoroughly with

high pressure potable water jets to remove any deposited salts.

11.6 PROTECTIVE COATINGS TO REINFORCEMENT

1 All the forgoing clauses of this part apply equally to epoxy coated reinforcing bars.

11.6.2 Epoxy Coated Reinforcing Bars

1 Reinforcing steel which are to be coated shall be free of slivers, scabs, excessive pitting,

rust, grease, oil and other surface defects detrimental to proper coating.

2 The surface shall be prepared in accordance with ISO 14654.

3 Coating shall be applied to the cleaned surface as soon as possible after cleaning and before

any visible oxidation to the surface occurs.

4 Reinforcing steel shall not have surface defects that would be detrimental to coating.

5 Coating material shall be epoxy resin powders as specified in ISO 14654 and ISO 14656 for

coating of reinforcing bars and as follows:

(a) epoxy resin powders which do not meet the above requirements must be tested by an

approved independent testing laboratory and accepted by the Engineer before use

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(b) only fusion bonded epoxy-coated reinforcing steel will be accepted

(c) no other means of epoxy coating will be approved.

6 Patching material shall be:

(a) furnished by the epoxy coating manufacturer

(b) compatible with the coating

(c) inert in concrete

(d) suitable for repairs to the coated reinforcing bars to be made by the coating applicator

and the Contractor at the project site.

7 Fabrication shall be performed before coating except as hereinafter specified for bent bars

and straight bars less than 7.6 m long.

8 Bent reinforcing steel bars shall be coated after bending, unless the fabricator can show that

satisfactory results can be obtained by coating before bending.

9 Any visible cracks in the coating on the outside of the bend or damage to coating resulting in

debonding of the coating after bending shall be rejected.

10 Bars less than 7.6 m long may be sheared or sawn to length after coating, provided:

(a) end damage to coating does not extend more than 12 mm back

(b) cut end is patched before any visible oxidation appears.

11 Flame cutting will not be permitted.

12 Epoxy coating shall be checked visually after cure for continuity of coating and shall be free

from holes, contamination, cracks and damaged areas.

13 There shall not be more than two holidays (pinholes not visually discernible) in any 300 mm

of the epoxy coated bar.

14 A holiday detector shall be used in accordance with the manufacturer's instruction to check

the epoxy coating for holidays. A 67.5 V detector such as the Tinker and Rasor Model M-1 or

its approved equivalent shall be used.

15 Patching of holidays is not required if there are less than three holidays per 300 mm length.

Bars having three or more holidays per 300 mm shall be cleaned and recoated or replaced

as directed by the Engineer.

16 Epoxy coating film shall be cured and/or post cured to a fully cured condition. A

representative proportion of each production lot shall be checked by the epoxy coating

applicator, using the method most effective for measuring cure to ensure that the entire

production lot of epoxy coating is supplied in the fully cured condition.

17 Contractor shall repair all coating damaged by fixtures used to handle or support the bars in

the coating process as follows:

(a) patching shall be done as soon as possible and before visible oxidation occurs

(b) excessive patching from other causes will not be permitted

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(c) satisfactory correction shall consist of proper adjustment of process, and rerunning

the bars through the plant.

18 The Engineer reserves the right for access to the epoxy coating applicator’s plant to witness

epoxy coating processes for project work and to obtain specimens from test bars for any

testing desired.

19 All chairs, tie wires and other devices used in connecting, supporting, securing or fastening

epoxy coated reinforcement steel shall be made of or coated with a dielectric material.

20 Before the reinforcement is lowered into place and before placement of the concrete, the

coated bars shall be inspected by the Engineer for damage to the epoxy coating.

21 Sheared ends of bars and other areas requiring limited repair due to scars and minor defects

shall be repaired, using the specified patching or repair materials.

11.6.3 Handling of Epoxy Coated Reinforcement

1 Reinforcement steel bars shall be handled and stored in a manner to prevent damage to bars

or, where used, the epoxy coating.

2 Bars, or where used epoxy coating, damaged in handling or other operations shall be

satisfactorily repaired at no additional cost to the Employer.

3 Where epoxy coated bars are used all handling systems shall have plastic mandrel and

padded contact areas wherever possible.

4 Where epoxy coated bars are used all bundling bands shall be padded.

5 All bundles shall be lifted with a strongback, multiple supports or a platform bridge so as to

prevent bar to bar abrasion from sags in the bar bundle.

6 Bars or bundles shall not be dropped or dragged.

7 During vibration care shall be taken to ensure that the epoxy-coated reinforcement is not

damaged by the pokers.

11.6.4 Testing of Epoxy Coated Reinforcement

1 Adhesion and flexibility of the epoxy coating shall be evaluated on test bars coated with each

production lot.

2 At least 1 % of the length or 6 m, whichever is less, of each size of bar to be coated shall be

furnished as test bars.

3 Test bars may be in one length or multiple lengths as required to have one test bar of each

size with each production lot.

4 The production epoxy coated test bars shall be evaluated by bending 120 (after rebound)

around a mandrel of a diameter corresponding to size of bar indicated in Table 11.1.

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Table 11.1

Mandrel Diameter for Bar Diameter for

Evaluation Test of Epoxy Coated Test Bars

Bar Diameter (mm)

Diameter of Mandrel (mm)

10 79

12 95

13 103

14 111

16 127

18 143

20 159

22 175

24 191

25 198

26 206

28 222

30 238

32 254

34 270

36 286

5 Bend shall be made at a uniform rate and may take up to one minute to complete.

6 Bend test shall be conducted at a room temperature of between 20 °C and 30 °C after the

specimen has been exposed to room temperature for a sufficient time to ensure that it has

reached thermal equilibrium.

7 No cracking of the epoxy coating shall be visible to the naked eye on the outside radius of the

bent bar.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 12: Joints

12 JOINTS.................................................................................................................... 2

12.1 GENERAL ............................................................................................................... 2

12.1.1 Scope 2

12.1.2 References 2

12.1.3 Submittals 2


12.1.5 Definitions 3

12.2 CONSTRUCTION JOINTS ...................................................................................... 4

12.2.1 General 4

12.2.2 Construction Joints in Water Retaining Structures 4

12.3 MOVEMENT JOINTS .............................................................................................. 5

12.3.1 General 5

12.3.2 Joint Filler 6

12.3.3 Joint Sealants 6

12.4 SLIP BEARINGS ..................................................................................................... 7

12.4.1 General 7

12.5 WATERSTOPS ....................................................................................................... 7

12.5.1 General 7

12.5.2 Waterstops 7

12.5.3 Butyl Rubber Waterstops 8

12.5.4 Water Swelling Gaskets 8

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12 JOINTS

12.1 GENERAL

12.1.1 Scope

1 This part deals with movement and construction joints, slip bearings, waterstops and

associated sealants and filler materials.


This Section

Part 1 ............... General

Part 10, ............ Curing

Part 15, ............ Hot Weather Concreting

Part 16, ............ Miscellaneous

12.1.2 References

ASTM D1751 .............. Standard Specification for Preformed Expansion Joint Filler for

Concrete Paving and Structural Construction (Non-extruding and

Resilient Bituminous Types)

ASTM D2240 .............. Standard Test Method for Rubber Property—Durometer Hardness

ASTM D3575 .............. Standard Test Methods for Flexible Cellular Materials Made From

Olefin Polymers

BS 903 ........................ Physical testing of rubber

BS 2571 ...................... General purpose flexible PVC compounds for moulding and extrusion

BS 2782, ..................... Methods of testing plastics

BS 6093, ..................... Design of joints and joining in building construction

BS 7164, ..................... Chemical tests for raw and vulcanized rubber

BS EN 1992-3 ............ Eurocode 2. Design of concrete structures. Liquid retaining and

containing structures

BS EN ISO 7214 ........ Cellular plastics. Polyethylene. Methods of test

CRD-C572 .................. Corps of Engineers Specifications for Polyvinylchloride Waterstop

ISO 9001 .................... Quality management systems. Requirements

12.1.3 Submittals

1 The Contractor shall submit for approval by the Engineer as soon as practicable after

acceptance of his Tender and not less than three weeks before commencement of

concreting, drawings showing his proposals for the position of construction joints having due

regard to any that may be shown on the Contract Drawings.




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2 For slide bearings the Contractor shall provide at least three samples of the proposed

material, together with the manufacturer's technical specifications and recommendations in

respect of application and performance.

3 For slip joints the Contractor shall provide at least three samples of materials proposed,

together with manufacturer's technical specifications and recommendations in respect of

application and performance.

4 For waterstops the Contractor shall provide at least three samples of proposed types,

including prefabricated joints and junctions, if applicable. If joints are to be made up on site,

provide worked samples, including samples for each make of waterstop, where samples

from different manufacturers are provided.

5 The Contractor must supply a certificate of compliance for the joint sealant, stating that it

meets the requirements of the specification. The Contractor shall also supply the

Manufacturer’s technical and installation data for the proposed material. The Contractor shall

provide details of previous installations of the product, with the client name, structure name,

type of joint and value of contract.

6 The Contractor shall prepare shop drawings that show the layout of the waterstops, specials

and joints.


1 The joint sealant, including primers and debonding materials shall be compatible with each

other and shall be supplied from a manufacturer operating the ISO 9001 or 9002 Quality

Assurance Scheme.

12.1.5 Definitions

1 Construction Joint: The surface where two successive placements of concrete meet, across

which it is desirable to develop and maintain bond between the two concrete placements, and

through which any reinforcement which may be present is not interrupted.

2 Contraction Joint: Formed, sawed, or tooled groove in a concrete structure to create a

weakened plane and regulate the location of cracking resulting from the dimensional change

of different parts of the structure. (See also Isolation Joint.)

3 Expansion Joint: A separation between adjoining parts of a concrete structure which is

provided to allow small relative movements such as those caused by thermal changes to

occur independently.

4 Isolation Joint: A separation between adjoining parts of a concrete structure provided to

isolate and element and thus allow independent movement.

5 Joints Fillers: Materials that are used to fill space within movement joints during construction.

They may provide support to a sealant applied subsequently.

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12.2 CONSTRUCTION JOINTS

12.2.1 General

1 Where construction joints are required in slabs or beams (designed by Direct Design Method

DDM) they shall be located within the middle third of their spans, and at one-third to one-

quarter of span in slabs and beams subject to a maximum spacing of approximately 9

metres. Where slabs are supported by beams then the beams and slabs shall be constructed

in one operation.

2 In all cases vertical stop boards of a form to be approved by the Engineer shall be provided

by at the end of each section of work which is to be concreted in one operation and the

concrete shall be thoroughly compacted against these stop boards.

3 Where slabs, beams and walls incorporate construction joints, panels shall generally be

constructed consecutively. Where this is not possible a gap not exceeding one metre shall be

formed between adjacent panels. This gap shall not be concreted until a minimum interval of

7 d has expired since the casting of the most recent panel.

4 The size of bays for reinforced floors, walls and roofs shall be as shown on the drawings but

in no event shall they exceed 7.5 m in either direction and 6 m when unreinforced or with

nominal reinforcement.

5 Horizontal construction joints in walls will only be permitted when the wall is continuous with

the floor slab. Walls shall be keyed on cast kickers 150 mm high or on the tops of walls

meeting the soffits of suspended members.

6 Construction joints in monolithic structures shall be aligned with each other whenever

practicable.

7 Before placing new concrete against concrete which has already set the latter shall be

treated to expose the aggregate over the full section and leave a sound irregular surface.

This shall be done while the concrete is still fresh by means of water spray and light brushing

or other means approved by the Engineer.

8 Immediately before the new concrete is placed all foreign matter shall be cleaned away and

the surface moistened.

9 If during the course of the Contract it should become apparent that the Contractor’s methods

of forming construction joints are not proving effective the Engineer may order the Contractor

to execute at the Contractor’s expense such preventative measures as the Engineer may

consider necessary to ensure the watertightness of the construction joints in further work.

12.2.2 Construction Joints in Water Retaining Structures

1 The floor may be designed as fully restrained against shrinkage and thermal contraction and

should be cast directly onto the blinding concrete.

2 In large structures, the floor shall be designed as a series of continuous strips with transverse

induced contraction joints provided to ensure that cracking occurs in predetermined

positions. Longitudinal joints between the strips should form contraction joints.

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3 Waterstops shall be incorporated into construction joints, crack induced joints, contraction

joints and expansion joints in water retaining structures. The Contractor shall ensure that all

such joints are watertight and any joints which may leak or weep shall be rectified by the

Contractor to the Engineer’s satisfaction.

4 The spacing of construction joints, crack induced joints, contraction joints and expansion

joints in water retaining structures shall be shown on the design drawings.

5 Where the positions or type of joints are not indicated on the drawings, the spacing of

construction joints or crack induced joints in water retaining structures shall not exceed 5 m.

6 Where the positions or type of joints are not indicated on the drawings in the ground floor

slab, construction joints, crack induced joints, contraction joints and expansion joints shall be

incorporated into the works as appropriate. for slabs on grade, construction joints or crack

induced joints should be provided at areas where differences in subgrade and slab support

may cause cracks. The slab shall be cast in strips not more than 15 metres wide across the

width of the building. Within each strip for both directions, crack induced joints shall be

provided at areas where cracks are expected and not more than 5.0 metre spacing, and

construction or contraction joints shall be provided at not more than 15.0m spacing.

7 Construction or contraction joints shall be provided between adjacent strips.

8 Waterstops of a type acceptable to the Engineer shall be embedded in the concrete. The

waterstop should be made of a high quality material, which must retain its resilience through

the service life of the structure for the double function of movement and sealing. The surface

of waterstops should be carefully rounded to ensure tightness of the joint even under heavy

water pressure. To ensure a good tightness with or without movement of the joints, the

waterstop should be provided with anchor parts. The cross-section of the waterstops should

be determined in accordance with the presumed maximum water pressure and joint

movements. The complete works of fixed and welded connections must be carried out

strictly in accordance with the manufacturer’s instructions.

9 Engineer’s acceptance shall be obtained by the Contractor, prior to start of work, on the

casting sequence and the layout of joints.

12.3 MOVEMENT JOINTS

12.3.1 General

1 Movement joints for expansion and contraction shall be constructed in accordance with the

details and to the dimension shown on the Drawings or where otherwise ordered by the

Engineer and shall be formed of the elements specified.

2 Movement Joints in Water Retaining Structures shall be in accordance with the details and to

the dimension shown on the Drawings and EN 1992-3.

3 The Contractor shall pay particular attention to the effects of climatic extremes on any

material which he may desire to use on any movement joint and shall submit for approval by

the Engineer his proposals for the proper storage, handling and use of the said materials

having due regard for any recommendations made by the manufacturer in this connection.

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12.3.2 Joint Filler

1 Joint fillers shall conform to the requirements of BS 6093 or ASTM D1751 or equivalent if

they are bituminous type or to the requirements of ASTM D3575 or BS EN ISO 7214 or

equivalent if they are polymer foam type.

2 The joint filler shall be fixed to the required dimensions of the joint cross-section and shall

provide a firm base for the joint sealer.

3 When required between two concrete surfaces as a resilient movement joint, the filler shall

be an approved granulated cork bound with insoluble synthetic resin.

4 When required between blockwork and concrete as a low density movement joint filler or for

building details it shall be an approved bitumen impregnated fibreboard or preformed closed

cell polyethylene.

12.3.3 Joint Sealants

1 All joints to be sealed shall be formed and the groove grit blasted to remove all traces of

deleterious materials such as form oil or curing compounds and also to remove any surface

laitance from the sides of the joint. The joint shall be dry prior the application of priming.

Where the use of grit blasting is not possible the Contractor may propose alternative

methods subject to the approval of the Engineer.

2 The back of the joint shall receive a debonding tape or polyethylene foam backer cord in

order to provide the correct depth to width ratio and prevent three sided adhesion.

3 The areas adjacent to the joint shall be protected using masking tape.

4 The sides of the joint shall be primed with the relevant primer as recommended by the

sealant manufacturer and the sealant material applied in accordance with the manufacturers

instructions.

5 The sealant material shall be a non-biodegradable multicomponent pitch polyurethane

elastomeric joint sealant, carefully selected as appropriate for the specific climatic and

environmental exposure conditions expected. Alternative types of sealant will be considered,

including epoxy-polyurethane, rubber bitumen and acrylic, subject to the requirements of the

specification and the approval of the Engineer.

6 Where the joint sealant is to be in contact with a protective coating the Contractor shall

satisfy the Engineer that the sealant and protective coating are compatible

7 Sealants shall exhibit the following properties:

(a) Movement accommodation factor 25 %

(b) Shore ‘A’ hardness 20 - 25

(c) Solids content 100 %

(d) Service temperature range 0 oC to 90

oC

(e) Chemical resistance to Sewage, Sabkha, Mineral acids and Alkalis

(f) Width to depth ratio 2:1

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8 Where shown on the Drawings sealants shall also be suitable for use with potable water.

9 All surface preparation, priming, mixing and application shall be carried out in strict

accordance with the manufacturer’s instructions.

10 The sealant shall have a proven track record of no less than ten years under similar local

conditions.

12.4 SLIP BEARINGS

12.4.1 General

1 Slip bearings shall be preformed low friction bearing strips to form a thin sliding joint.

2 They shall be extruded from specially formulated polyethylene to form a durable lamina

resistant to sewage, mineral acids and alkalis, solvents and weathering.

3 Slip bearings shall be applied in two layers with the bottom layer bonded to the substrate with

a high quality solvent borne adhesive based on polychloroprene rubber. The substrate shall

be clean and free from deleterious materials such as form oil or curing compounds and

surface laitance. The surface shall be level and even along the full length of the joint

4 The applied loads for slip bearings shall not exceed 0.7 MPa.

5 Operating temperatures shall be up to 80 C

6 The coefficient of friction shall not exceed 0.15

12.5 WATERSTOPS

12.5.1 General

1 Waterstops and associated materials shall be by a manufacturer with a minimum of ten years

experience in the field of engineering waterproof products.

2 PVC waterstops shall be suitable for storage, handling, installation and service within a range

of 15 C to 65 C.

12.5.2 Waterstops

1 The waterstop shall be a high performance system forming a continuous network as shown

on the Drawings.

2 Site jointing is to be limited to butt joints and shall be performed strictly in accordance with

the manufacturer’s instructions.

3 Centrally placed waterstops shall employ centre bulbs/shutter stop with ribs on the web

sections.

4 Externally placed waterstops shall have ribs on either side of the centre of the waterstop. The

water bar used at the location of expansion joints shall have a bulb in the centre to

accommodate the movements.

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5 Waterstops shall have a minimum thickness of 3 mm.

6 The minimum test performance data for PVC waterstops shall be as follows:

Tensile strength >12 MPa

Elongation at break 300 %

Hardness Shore ‘A’ 80 to 90

7 The materials shall be tested in accordance with BS 2571 or BS 2782 or CRD–C572 or

ASTM D2240.

12.5.3 Butyl Rubber Waterstops

1 Butyl rubber waterstops shall have the properties stated in Table 12.1 when tested in

accordance with BS 903.

Table 12.1

Properties Requirements of Butyl Rubber Waterstops

BS 903

Property

Requirements

Part A1 Density 1100 kg/m3 (± 5 %)

Part A26 Handness 60-70 IRHD

Part A2 Tensile Strength Not less than 17.5 N/mm2

Part A2 Elongation at break point Not less than 450 %

Part A/6 Water Absosption (48 hours immersion) Not exceeding 5 %

2 Butyl rubber waterstops shall be suitable for storage, handling, installation and service within

a temperature of 0 °C to 40 °C

12.5.4 Water Swelling Gaskets

1 Where active sealing is required for critical areas, waterstops shall be hydrophilic polymer

modified chloroprene rubber strips. The rubber strips shall conform to the following properties

as applicable:

(a) Water pressure resistance : 5 Bar (50 m)

(b) Expansion in contact with water : 2 x original SRE

(c) : Reversible

(d) Application Temperatures : - 30 to + 70 °C

2 The selected rubber strips shall be available for three exposures:

(a) Fresh Water

(b) Seawater

(c) Chemicals (if the condition demands or upon the Engineer’s request)

The supplier shall furnish references upon request of the Engineer.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 13: Inspection and Testing of Hardened Concrete

13 INSPECTION AND TESTING OF HARDENED CONCRETE .................................. 2

13.1 GENERAL ............................................................................................................... 2

13.1.1 Scope 2

13.1.2 References 2

13.1.3 Submittals 2


13.1.5 Non-Compliance of Work 3

13.1.6 General Fieldwork Requirements 4

13.2 CONCRETE CORES ............................................................................................... 4

13.2.1 General 4

13.2.2 Drilling Cores 5

13.2.3 Testing for Strength 6

13.2.4 Assessment of Strength 7

13.3 REINFORCEMENT COVER MEASUREMENTS ..................................................... 7

13.4 ULTRASONIC PULSE MEASUREMENTS .............................................................. 8

13.4.1 General 8

13.4.2 Selection of Test Locations 8

13.4.3 Execution of Tests 8

13.4.4 Estimated In-Situ Cube Strength 9

13.5 RADIOGRAPHY OF CONCRETE ........................................................................... 9

13.6 SURFACE HARDNESS ........................................................................................... 9

13.6.1 General 9

13.6.2 Method of Test 9

13.6.3 Equipment 10

13.6.4 Reporting 10

13.7 CHEMICAL CONTENT .......................................................................................... 10

13.7.1 Sampling 10

13.7.2 Laboratory Testing 11

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13 INSPECTION AND TESTING OF HARDENED CONCRETE

13.1 GENERAL

13.1.1 Scope

1 This Part of the specification covers the inspection, sampling and testing of hardened

concrete.

2 Related Section and Parts are as follows:

This Section


13.1.2 References

1 The following standards are referred to in this part of the specification:

ACI 214.4R ................. Guide for Obtaining Cores and Interpreting Compressive Strength

Results

ACI 318 ERTA ............ Building Code Requirements for Structural Concrete (ACI 318-08) and

Commentary

ASTM C42 .................. Standard Test Method for Obtaining and Testing Drilled Cores and

Sawed Beams of Concrete

ASTM C823 ................ Standard Practice for Examination and Sampling of Hardened

Concrete in Constructions

BS 1881-124 .............. Testing concrete. Methods for analysis of hardened concrete

BS 1881-204, ............. Testing concrete. Recommendations on the use of electromagnetic

covermeters


BS EN 12504-1 .......... Testing concrete in structures cored specimens taking, examining and

testing in compression

BS EN 12504-2 .......... Non-destructive testing. Determination of rebound number

BS EN 12504-3:2005 Testing concrete in structures. Determination of pull-out force

BS EN 12504-4 .......... Determination of ultrasonic pulse velocity

BS EN 13791 .............. Assessment of in-situ compressive strength in structures and precast

concrete components


concrete core .

13.1.3 Submittals

1 The Contractor shall submit to the Engineer his quality assurance procedures for the

particular parts of the testing work that will be carried out.

2 The Contractor shall submit for the Engineer’s approval the curriculum vitae (CV) of the

supervisor proposed for the work.






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3 The Contractor shall through testing agency prepare a factual report that identifies the test

methods used and the test results. The report shall also identify any unusual results or

pertinent information relating to the testing. The report shall be presented in hard and

electronic copies.

4 For each of the test results the Contractor shall identify the precision or repeatability of the

particular sampling and testing method. This shall be as given from experience of the

particular test by the laboratory or as expected from information in the particular test

standard.

5 In-place tests will be valid only if the tests have been conducted using properly calibrated

equipment in accordance with recognized standard procedures and acceptable correlation

between test results and concrete compressive strength has been established and is

submitted.

6 Non-destructive tests shall not be used as the sole basis for accepting or rejecting concrete,

but they may be used to “evaluate” concrete when the standard-cured strengths fail to meet

the specified strength criteria


1 All field and laboratory testing of concrete shall be carried out by an independent laboratory

approved by the Engineer.

2 The evaluation of concrete in structure is needed when an existing structure is to be modified

or redesigned; to assess structural adequacy when doubt arises about the compressive

strength in the structure due to defective workmanship, deterioration of concrete due to fire or

other causes;when an assessment of the in-situ concrete strength is needed during

construction; to assess structural adequacy in the case of non-conformity of the compressive

strength obtained from standard test specimens; assessment of conformity of the in-situ

concrete compressive strength when specified in a specification or product standard.

13.1.5 Non-Compliance of Work

1 If the 28 d works test cubes as defined in clause 6.6 of this Section fail to meet the minimum

criteria, the Engineer shall direct the Contractor to carry out in-place methods to estimate the

concrete strength by non-destructive testing, in-situ drilling of concrete cores or load testing.

2 The parts or elements of the structure made from the defective batch or batches of concrete

as represented by the works test cubes shall be identified by the Engineer and based on this

information the Engineer shall instruct the Contractor on the required number and position of

concrete cores.

3 The Engineer shall review the concrete core test results in conjunction with BS EN 13791 or

ACI 318 whichever is applicable to the structural design.

4 Based on this assessment the Engineer shall decide the acceptability of the concrete in the

structural element and may either:

(a) accept the concrete

(b) instruct that certain remedial works are carried out

(c) instruct that the element is replaced.

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13.1.6 General Fieldwork Requirements

1 The Contractor shall make all arrangements to provide safe stable access to testing

locations.

2 When gaining access to testing locations and whilst testing the Contractor shall take care not

to damage the structure or leave it in an untidy or unclean state.

3 The Contractor shall take precautions to ensure that cooling water from concrete coring/other

operations is discharged such as not to cause a mess or damage the interior or exterior parts

of the structure.

4 The Contractor shall be responsible for arranging the water supply required for testing.

5 The Contractor shall arrange for a suitable power supplies. Where testing is being carried out

on an occupied structure a power supply from the building services may not available and the

Contractor shall make arrangements for power supply and extension leads of adequate

length.

6 The Contractor shall appoint a qualified field supervisor to co-ordinate and manage the field

work. The supervisor shall have not less than five years experience of such work.

7 Before starting the work, the Engineer with the Contractor’s supervisor will mark the positions

where field testing is to be carried out. A unique referencing system to identify each sample

or testing location will be adopted, and this will either be referenced on sketch plans or

drawings or by a detailed description used throughout the report to identify test locations.

8 If testing is being carried out on an occupied structure the Contractor shall co-ordinate with

the owner or operator of the structure to arrange the detailed programme for the works and

gain access to the various parts of the structure.

9 As soon as laboratory test results are available these shall be submitted by hand or faxed to

the Engineer in draft form. The testing laboratory, or technical bureau assigned by the testing

agency, assigned by the contractor shall provide a technical report providing visual

information and analysing the tests conducted.

10 All core holes, dust sample holes and exploratory investigation areas shall be reinstated with

a proprietary non shrink cementitious repair mortar. The preparation of the hole or area

before reinstatement shall be carried out as per the recommendation of the repair mortar

supplier.

11 Before filling any core holes, dust sample holes or exploratory investigation areas, the

Contractor shall allow the Engineer time to inspect these areas and obtain written

confirmation from the Engineer before filling.

13.2 CONCRETE CORES

13.2.1 General

1 The drilling and testing of cores shall be carried out in accordance with BS EN 13791 & BS

EN 12504-1, or GSO ISO 1920-6 or ASTM C42 and ACI 214.4 whichever is applicable to the

structural design.

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2 All of the supplementary information listed by the relevant standards shall be included in the

test report with photographs of the cores.

3 An assessment of in-situ compressive strength for a particular test region shall be based on

at least 3 cores. Consideration shall be given to any structural implications resulting from

taking cores. The diameter of concrete core shall be at least 100 mm for strength evaluation

unless clear spacing of reinforcement is less than 100 mm and approved by Engineer.

4 The preferred minimum core diameter is three times the nominal maximum size of the

coarse aggregate, but it shall be at least two times the nominal maximum size of the coarse

aggregate

5 The Engineer will advise the required number and locations of cores. If the results of the

initial coring are inconclusive, the Engineer may instruct that further cores be taken at certain

locations.

6 Unless otherwise directed by the Engineer, the Contractor shall ensure that coring does not

cut through any reinforcing steel. The required diameter and depth of concrete cores shall be

as stated in table 13.1

Table 13.1

Minimum Depth of Sampling of Concrete for Testing Purposes1 (ASTM C823)

Types of Construction Thickness of

Section, m

Minimum Depth to Be

Sampled, m

Slabs, pavements, walls, linings, foundations,

structural elements accessible from one side

only

0.3 or less entire depth

0.3 or greater 0.3

Suspended slabs2, walls, conduits,

foundations, structural elements exposed to

the atmosphere at two or more sides;

concrete products

0.15 or less entire depth

0.15 – 0.6 one half the thickness or

0.15 whichever is greater

Massive sections 0.6 or greater 0.6

1 The requirements of table 13.2.1 may not provide the quantities or dimensions of samples

that are required for all tests, in that case, the necessary additional quantity of concrete in

pieces of appropriate minimum size should be taken at each sampling location.

2 When suspended slabs are cored, it is desirable to leave the lower 25 mm uncored, so as

not to lose the core by its falling from the barrel and to make it easier to patch the core hole.

13.2.2 Drilling Cores

1 Before beginning coring operations the Contractor shall use a proprietary cover meter to

identify the position of steel reinforcing bars at the testing location.

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2 The Engineer may instruct that the core is taken through the concrete without hitting any

reinforcement or the Engineer may instruct that the core is taken in a position where it is

expected reinforcement will be cut in order to provide a sample of the reinforcement to check

its condition. The locations of all drilling points shall be chosen so that the core contains no

steel parallel to its length.

3 Before capping, the core shall have a length of at least 95 % of its diameter. Once prepared

for test the core shall have a length at least equal to the diameter and not more than 1.2

times its diameter.

4 Cores of both 100 mm and 150 mm nominal diameters may be tested provided that the

aggregate size does not exceed 20 mm and 40 mm respectively. Where possible 150 mm

cores should be taken to reduce the variability due to drilling and increase the reliability of the

testing, unless reinforcement is congested and the use of 100 mm cores will reduce the

possibility that the core will contain steel or it is necessary to restrict the sampling to a length

of less than 150 mm.

5 Where the size of the section precludes the use of 100 mm or 150 mm cores, smaller cores

may be used with the permission of the Engineer.

6 During drilling operations, a log of observations that may affect the interpretation of core

samples shall be prepared.

7 If instructed by the Engineer, immediately after the core has been cut and removed and the

structure a carbonation test will be carried out by using a 1 or 2 % solution of phenolphthalein

poured over the cut surface. A photograph shall be taken of the cut core with the

phenolphthalein solution applied to provide a record of the test.

8 If during the drilling of the core, the core collapses due to weak honeycombed or defective

concrete, the Contractor shall stop the drilling operation and carry out testing at an adjacent

location as advised by the Engineer. If when testing at the second location, the core again

breaks due to honeycombed or defective concrete the freshly cut core shall be retained for

reference and a note made of the condition.

13.2.3 Testing for Strength

1 The compressive strength of field concrete cores shall be assessed in accordance with BS

EN 13791.

2 The details of the concrete core in accordance with BS EN 13791 shall be recorded and two

photographs on either side of the core taken.

3 Where there is reinforcement in the core, the size and the type of bar shall be noted along

with its cover to the concrete surface, the condition of reinforcing bars shall be noted with a

detailed description of any corrosion of the reinforcement.

4 Before carrying out the compressive strength testing of the cores, the Contractor shall inform

the Engineer to allow him to witness the testing if required.

5 Crushed core samples shall be retained by the laboratory and only disposed of after written

approval by the Engineer.

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13.2.4 Assessment of Strength

1 The estimated in-situ strength of the concrete shall be calculated from the core result using

BS EN 13791, ACI 214.4 or ACI 318 whichever is applicable by the structural design.

13.3 REINFORCEMENT COVER MEASUREMENTS

1 The measurement of cover to reinforcing steel and other metallic items in concrete shall be

carried out in accordance with BS 1881 Part 204 using an electromagnetic device that

estimates the position depth and size of the reinforcement.

2 The locations for checking cover and the spacing between measurements shall be advised

by the Engineer based on the objective of the investigation. The Contractor shall carry out

calibrations of the electric magnetic device for a particular bar size to allow the bar diameter

to be measured.

3 While testing, the orientation of steel bars shall be checked.

4 The electromagnetic device shall incorporate scale or digital display range and shall be

calibrated in accordance with BS 1881 Part 204. When calibrated in this manner the

indicated cover to steel reinforcement shall be accurate to within 5 % or 2 mm which ever

is the greater over the working range given by the manufacturer.

5 The cover meter shall be used in accordance with the manufacturers instructions and checks

on the zero carried out as specified.

6 The search head shall be traversed systematically across the concrete, and, where

reinforcement is located, rotated until the maximum disturbance with electromagnetic field is

indicated by the meter.

7 The cover to the reinforcement shall be noted along with the axis of the reinforcement. The

cover shall also be recorded on the concrete surface with chalk or a suitable non-permanent

marking pen.

8 Care should be taken to avoid interference from other metallic sources or magnetic material.

9 The cover meter checks shall be carried out by an operator with five years experience.

10 The test report on cover shall include the following information:

(a) date

(b) time and place of test

(c) description of the structure or component under investigation

(d) location of test areas

(e) make and type of cover meter used

(f) date of last laboratory calibration of cover meter

(g) details of site calibration of cover meter, indicated values of cover

(h) estimated accuracy of quantitative measurements

(i) configuration of steel reinforcement

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13.4 ULTRASONIC PULSE MEASUREMENTS

13.4.1 General

1 The ultrasonic velocity test equipment shall be capable of measuring the transit time of a

pulse vibration through concrete. The length of the pulse part between the transducer

equipment shall be measured, and the pulse velocity calculated.

2 Ultrasonic pulse velocity testing shall be carried out in accordance with the provisions of BS

EN 12504-4.

3 Velocities shall be measured at a number of locations around a structure and a velocity

contour of the structure established. A minimum of 40 velocities shall be measured for each

structural element.

13.4.2 Selection of Test Locations

1 Wherever possible direct transmission arrangements shall be used. The transducers shall be

mounted on a specially formed moulded surface.

2 The minimum path length shall be 100 mm for concrete in which the nominal maximum size

of aggregate is 20 mm or less and 150 mm for concrete in which the nominal maximum size

of aggregate is between 20 mm and 40 mm. but the path length shall not be longer than

required to detect small regions of bad concrete.

3 Where concrete contains steel the pulse velocity shall be adjusted in accordance with the

requirement of BS EN 12504-4.

4 Locations that contain reinforcement directly along or close to the pulse paths shall be

avoided.

5 Where repositioning is not possible the semi-direct transmission measurement, where

transducers are placed on adjacent faces of the concrete, may be used.

13.4.3 Execution of Tests

1 Positions chosen for the test locations shall be clearly and accurately marked on the surface

of the concrete.

2 The surface of the concrete shall be shall be cleaned and free from grit and dust. Path

lengths shall be determined to an accuracy of 1 % and a suitable couplant (such as grease)

applied to each of the test points.

3 Pulse transit times shall be measured by a skilled operator, with a minimum of five years

experience in the use of the equipment.

4 Pulse velocity measurement equipment shall be in accordance with the requirements of BS

EN 12504-4.

5 Test results shall be examined and any unusual readings repeated carefully for verification or

amendment.

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13.4.4 Estimated In-Situ Cube Strength

1 A correlation shall be established between the cube crushing strength of the particular mix

used in the structure and the pulse velocity.

2 Where it is not possible to obtain cubes with the same mix design as the original structure a

combination of coring and ultrasonic pulse velocity testing may be carried out at the direction

of the Engineer, where the cores are used to provide the correlation information required for

the interpretation of the ultrasonic pulse velocity tests.

13.5 RADIOGRAPHY OF CONCRETE

1 Gamma rays and high energy X-rays, which illustrate by radiographs the concrete defects:

The testing shall be carried out in accordance with the requirements of BS 1881-205 or

equivalent.

13.6 SURFACE HARDNESS

13.6.1 General

1 Testing of concrete surfaces for hardness using rebound hammers shall be carried out in

accordance with BS EN 12504-2.

2 The rebound hammer shall only be used for estimation of concrete strength where a specific

correlation is carried out of the concrete from the structure being tested; this shall be from

works test cubes or cores taken from the structure.

3 The correlation between concrete strength and the rebound number shall be carried out in

accordance with BS EN 12504-2. The precision of the correlation curve between the mean

rebound number and strength shall be stated and this shall be used when reporting any

strength interpretations from surface hardness readings. The use of general manufacturers’

correlation or calibration curve for strength shall not be used.

4 It should be noted that the rebound hammer number only provides information on a surface

layer of approximately 30 mm in depth of the concrete and that this should be quoted in the

test report.

5 The rebound hammer maybe used to establish the uniformity of the finish products or similar

elements in a structure at a constant age, temperature, maturity and moisture condition.

13.6.2 Method of Test

1 A minimum of 12 readings shall be taken to establish a single surface hardness at a

particular location.

2 The reading shall be on a regular grid between 20 mm to 50 mm spacing over an area not

exceeding 300 mm by 300 mm.

3 The mean of each set of readings shall be calculated including abnormally high and

abnormally low results unless there is good reason to doubt the validity of a particular

reading.

4 The coefficient of variation and the standard deviation of the readings shall be reported.

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13.6.3 Equipment

1 The rebound hammer shall be a proprietary type that has been used successfully and

serviced for a minimum of five years.

2 The hammer shall comprise of a mass propelled by a spring that strikes a plunger in contact

with the surface.

3 The manufacturers’ literature shall identify the impact energy and contact area of the plunger

for the hammer.

13.6.4 Reporting

1 The test report shall affirm that the hardness was determined in accordance with BS EN

12504-2 and shall provide the following information:

(a) date time and place of test

(b) description of structure and location of test

(c) details of concrete

(d) type of cement

(e) cement content

(f) type of aggregate

(g) type of curing

(h) age of concrete

(i) type of compaction of concrete

(j) forming of surface

(k) moisture condition of the surface

(l) carbonation state of surface

(m) any suspected movement of the concrete under test

(n) direction of test

(o) any other factors that are considered significant in influencing the hardness readings.

2 The details of the rebound hammer correlation with strength including the mean, range,

standard deviation and coefficient and variation of each reading shall also be included.

13.7 CHEMICAL CONTENT

13.7.1 Sampling

1 The Engineer shall instruct the depth increments over which the dust samples are to be

taken, the types of chemical testing to be carried out and the quantity of sample required.

2 The depth of sample shall not be less than the concrete cover to the reinforcement and at

least 50 mm from the surface of concrete. In presence of reinforcement, the chemical

content shall be tested at least at two levels before and after the depth of reinforcement from

the surface of concrete.

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3 To provide uniform samples of cement matrix and aggregate, three separate holes shall be

drilled at one location. The diameter of the holes shall be between 12 and 20 mm.

4 Care shall be taken to discard the material from any render or finish unless this is specifically

required under the investigation.

5 Care shall be taken to ensure that dust increments are accurately measured by marking the

drill bit.

6 The dust samples increments shall be carefully transferred to plastic bags and sealed to

avoid contamination. Each sealed bag shall be uniquely identified by the sample identification

and depth increment.

13.7.2 Laboratory Testing

1 Residual split samples of dust from the field investigation shall be retained until the Engineer

has reviewed the chloride test results. The Engineer may instruct that repeat tests are carried

out on certain samples.

2 Chloride testing of concrete dust samples shall be by an acid soluble method in accordance

with BS 1881 Part 124. The results shall be reported to two decimal places.

3 Sulphate testing of concrete dust samples shall be in accordance with BS 1881 Part 124,

using an acid soluble method.

END OF PART

QCS

QCS 2014 Section 05: Concrete Page 1 Part 14: Protective Treatments for Concrete

14 PROTECTIVE TREATMENTS FOR CONCRETE ................................................... 2

14.1 GENERAL ............................................................................................................... 2

14.1.1 Scope 2

14.1.2 References 2

14.1.3 Submittals 2


14.1.5 Preinstallation and Co-ordination 4

14.1.6 Delivery, Storage and Handling 4

14.1.7 Protection 4

14.1.8 General Requirements for all Treatments 5

14.1.9 Final Inspection 5

14.2 EPOXY COATING ................................................................................................... 5

14.2.1 General 5

14.2.2 Surface Preparation 5

14.2.3 Materials 6

14.2.4 Application 6

14.3 WATERPROOF MEMBRANE ................................................................................. 6

14.3.1 General 6

14.3.2 Materials 7

14.3.3 Waterproof Membrane 7


14.4 PENETRATIVE PRIMER ......................................................................................... 8

14.4.1 General 8

14.4.2 Material 8



14.5 PROTECTIVE COATING ........................................................................................ 9

14.5.1 General 9


14.5.3 Material 10


14.6 PLASTIC SHEET LINER FOR CONCRETE STRUCTURES ................................. 11

14.6.1 General 11

14.6.2 Shop Drawings and Submittals 11

14.6.3 Liner Material Requirements 11

14.6.4 Plastic Sheet Liner Strip Properties 12

14.6.5 Basic Sheet Dimensions 12

14.6.6 Liner Details 12

14.6.7 Installation 13

14.6.8 Testing Requirements 13

14.6.9 Special Requirements 14

14.6.10 Joints in Lining for In-Situ Concrete Structures 15

14.6.11 Testing and repairing damaged surfaces 15

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14 PROTECTIVE TREATMENTS FOR CONCRETE

14.1 GENERAL

14.1.1 Scope

1 This Part covers the materials and application requirements for coatings for concrete

surfaces including epoxy coatings, waterproof membranes, penetrative primers, protective

coatings, and coatings and treatments for specialist applications where there is a harsh

environment.


This Section

Part 1, ............. General

14.1.2 References


ASTM D412 ................ Test Methods for Vulcanized Rubbers and Thermoplastic Elastomers

Tension

ASTM D543 ................ Test Method for Resistance of Plastics to Chemical Reagents

ASTM D570 ................ Test Method for Water Absorption of Plastics

ASTM D638 ................ Test Method for Tensile Properties of Plastics (Metric)

ASTM D746 ................ Test Method for Brittleness Temperature of Plastics and Elastomers

by Impact

ASTM D882 ................ Test Methods for Tensile Properties of Thin Plastic Sheeting

ASTM D1000 .............. Test Method for Pressure Sensitive Adhesive Coated Tapes Used for

Electrical and Electronic Applications

ASTM D1004 .............. Test Method for Initial Tear Resistance of Plastic Film and Sheeting

ASTM D4541 .............. Test Method for Pull Off Strength of Coatings Using Portable Adhesion

Testers

ASTM E 96 ................. Test Methods for Water Vapor Transmission of Materials

ASTM E154 ................ Test Methods for Water Vapor Retarders Used in Contact with Earth

Under Concrete Slabs, on Walls, or as Ground Cover

BS 1881 ...................... Testing Concrete


CIRIA Technical Note 130, Protection of Reinforced Concrete by Surface Treatments.

ISO 9000 .................... Quality management and quality assurance standards

ISO 9001 .................... Quality systems - Model for quality assurance in design, development,

production, installation and servicing

14.1.3 Submittals

1 The Contractor shall submit manufacturers' specifications, installation instructions and other

data to show compliance with the requirements of this part of the specification and the

Contract Documents.

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2 The Contractor shall submit samples of all materials to be used in the works before delivery

of material to Site. Samples of membrane waterproofing shall be 300 mm square. Samples

of liquid components shall be a minimum of one litre.

3 The Contractor shall submit comprehensive test results for the protective coating system as

per the tests in the specification which shall clearly indicate whether the values are mean

values measured in current production or minimum values which the property does not fall

below.

4 The Contractor shall clearly state the chemical composition of the material and the process

by which protection is given to the concrete.

5 In addition to the test methods identified in this clause of this specification, the Engineer may

require the Contractor to carry out further tests to different standards.

6 If the Contractor wishes to propose a material which has been tested to alternative

standards, the Contractor shall submit correlation tests showing the comparable values of the

two test methods. These test results shall be comprehensive giving full details of the sample

conditioning, preparation, method of test, criteria for assessment etc.

7 The Contractor shall submit comprehensive information of previous applications of the

material in similar conditions and environments. This information shall include: project name,

type/grade of material used, quantity of material used, name of client, name of consultant,

name of Contractor. If requested by the Engineer, the Contractor shall supply the contact

details of the client, consultant or Contractor where the material was previously installed.

8 The Contractor shall submit a guaranty for the protective coating system and the

workmanship. The guaranty shall be worded to reflect the required performance of the

material and shall be approved by the Engineer. The guaranty shall be worded to include the

phrase ‘the Contractor shall, at the convenience of the Employer, effect all repairs and

replacements necessary to remedy defects all to the complete satisfaction of the Engineer’.

Unless stated otherwise in the contract specific documentation, the performance guaranty

shall be for a period of ten years except for the penetrative primer which shall be for a period

of five years.

9 The use of alternatives may be considered by the Engineer. If the Contractor wishes to

propose such systems, a technical submission shall be made which shall include a

comprehensive justification giving an explanation of why the proposed system is equivalent

or superior to the one designated.


1 The protective coating system shall be supplied by a manufacturer who is certified to the

ISO 9000 series of quality standards. The Contractor shall submit to the Engineer a copy of

the ISO 9000 series certificate that clearly states the scope of the certification.

2 The protective coating system shall be supplied by a manufacturer who provides technical

assistance on the suitability for the application and installation for the material. For the initial

use of the material on Site, the Contractor shall arrange for the technical representative of

the manufacturer to be present to demonstrate the correct use of the material.

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3 The protective coating system shall be applied by a contractor or subcontractor who is

certified to the ISO 9000 series of quality standards. The Contractor shall submit to the

Engineer a copy of the ISO 9000 certificate that clearly states the scope of the certification.

the Engineer may permit the use of an applicator who is not certified to ISO 9000 if the

applicator works to a quality system that is approved by the Engineer.

4 The works shall be executed by an approved specialist subcontractor having a minimum of 5

years successful experience in the installation of the specified material. Only tradesmen

experienced with the installation of the materials specified shall be used.

14.1.5 Preinstallation and Co-ordination

1 After approval of all materials and before installation, a prework conference with the Engineer

shall be held at the Site. The meeting shall be attended by representatives of the Engineer,

Contractor, subcontractor, and manufacturer.

2 The parties shall:

(a) review drawings, specifications and approved materials

(b) correct conflicts, if any, between approvals and specification requirements

(c) examine Site conditions, including inspection of substrate, material labels and

methods of storing materials

(d) review installation procedures and scheduling

(e) review protection methods for finished work from other trades.

3 Before applying the coating system to the permanent works the Contractor shall carry out a

small trial of the coating system for the review and approval of the Engineer.

14.1.6 Delivery, Storage and Handling

1 Materials shall be delivered in their original, tightly sealed containers or unopened packages,

all clearly labelled with the manufacturer's name, brand name, and number and batch

number of the material where appropriate. Materials and equipment shall be stored as

directed in a neat and safe manner.

2 Storage areas shall comply with the manufacturers requirements with regard to shade,

ventilation and temperature limits and shall be located away from all sources of excess heat,

sparks or open flame. Containers of liquid material shall not be left open at any time in the

storage area.

3 Materials not conforming to these requirements will be rejected by the Engineer and shall be

removed from the Site and replaced with approved materials.

4 The Contractor shall deliver materials to Site in ample time to avoid delay in job progress and

at such times as to permit proper co-ordination of the various parts.

14.1.7 Protection

1 The Contractor shall protect the protection system installation from damage during the

construction period so that it will be without any indication of abuse, defects or damage at the

time of completion.

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2 The Contractor shall protect the building/structure from damage resulting from spillage,

dripping and dropping of materials.

3 The Contractor shall prevent any materials from running into and clogging drains.

4 Materials and plant shall not be stored on any newly constructed floor without the permission

of the Engineer.

5 Impervious membranes shall be laid as protection to all concrete surfaces in contact with the

soil and shall consist of tanking or similar accepted material, based on soil investigation

report.

6 All foundations shall be provided with protection such as epoxy coatings or similar other

accepted equivalents so that concrete is not exposed to harmful effects of soil, chlorides etc.

14.1.8 General Requirements for all Treatments

1 Protective treatments shall be applied where designated in the contract specific

documentation.

2 All protective coating systems to be used shall be applied strictly in accordance with the

manufacturers recommendations.

3 The Contractor shall take all necessary precautions against fire and other hazards during

delivery, storage and installation of flammable materials specified herein and comply any

regulations imposed by the Civil Defence Department of the Ministry of the Interior in respect

of the storage and use of hazardous materials required under this section.

4 The Engineer shall specify the required final colour of the coating and the Contractor shall

submit samples showing the colour before ordering the materials.

14.1.9 Final Inspection

1 Upon completion of the installation, an inspection shall be made by a representative of the

material manufacturer in order to ascertain that the system has been properly installed.

14.2 EPOXY COATING

14.2.1 General

1 The coating shall be a decorative flexible high solids, epoxy polyurethane coating applied in

two coats to a dry film thickness of 200 m minimum.

14.2.2 Surface Preparation

1 The surface of the concrete shall be free from oil, grease, loose particles, decayed matter,

moss or algae growth and general curing compounds. All surface contamination and surface

laitance shall be removed by high pressure water jetting or sweep blasting.

2 Blow holes and areas of substantial pitting shall then be filled with a solvent free thixotropic

epoxy resin fairing coat. The mixing and application of this coat shall be in accordance with

the product manufacturer’s recommendations.

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3 Where surface cracking is apparent these cracks shall be chased, by an approved

mechanical means, to the depth of the crack. A thixotropic epoxy resin shall be applied using

a trowel, scraper or filling knife ensuring that full compaction is achieved into the chased

section and providing a flush finish with the concrete surface. A minimum period of 24 h shall

be allowed before applying any subsequent protective coating systems.

14.2.3 Materials

1 External above ground coating materials shall provide protection against chlorides and

carbonation, and be UV and abrasion resistant.

2 The above ground coating shall be applied over the below ground coating and shall continue

for a minimum of 150 mm above the ground level.

3 The epoxy coating shall be UV stable.

4 The finished coating shall be pinhole free and have a total minimum dry film thickness of

200 m.

5 The materials used in the coating system shall comply with the following requirements:

Solids content > 85 %

Service temperature -20 C to 70 C Tensile strength (DIN 53504) 4 MPa Resistance against crack (DIN 53515) 6 MPa Adhesion to concrete (ASTM D-4541) greater than 3.5 MPa Compressive strength (ASTM D-695) 90 MPa (neat resin) Tensile elongation (ASTM D-638) 6-8 % (neat resin) Water absorption (MIL D-24613) Nil Abrasion resistance (ASTM C-501) 50 mg Compressive strength (ASTM C-579) 97 MPa @ 7 days Thermal coefficient of expansion (ASTM C-531) 46.8 x 10

-6 mm/mm/degree C

14.2.4 Application

1 Where required by the Engineer, trial areas not exposed in the finished work shall first be

treated using the selected materials.

2 The exposed concrete surfaces as defined in the documents or as agreed with the Engineer

shall be treated with the material.

3 The coating shall be applied by spray, roller or brush to achieve a finish acceptable to the

Engineer.

4 In all operations of storage, mixing and application, the Contractor is to comply with the

health and safety recommendations of the manufacturer and governing authorities.

14.3 WATERPROOF MEMBRANE

14.3.1 General

1 This Subpart covers the use of waterproof membrane for general protection to buried

concrete.

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2 Where indicated on the Drawings or directed by the Engineer, concrete in contact with the

ground shall be protected by a preformed flexible self-adhesive bituminous type membrane.

3 The laying, lapping and sealing of the membrane shall be in accordance with the

manufacturer’s instructions.

14.3.2 Materials

1 The material shall be an externally applied waterproof membrane shall be an impervious,

cold applied flexible laminated sheet, consisting of multilayer high density cross-laminated

polyethylene film with a backing of self-adhesive rubber bitumen compound, protected with

silicone coated release paper.

2 Primer for Sheet Membrane: As recommended by the manufacture of the sheet membrane.

3 Protection Board: Provide a minimum 6 mm thick asphalt protection board manufactured

from selected aggregates, bound in modified bitumen encased between two layers of

strengthened asphalt paper. The bituminous material shall be a minimum of 1.0 mm thick

and the membrane shall be capable of bridging crack widths in the substrate up to 0.6 mm

wide.

14.3.3 Waterproof Membrane

1 The material shall be suitable for use in the Gulf region the compound shall be specially

formulated for hot climates and shall have proven experience in the Middle East.

2 The waterproofing material shall conform to the standards detailed in Table 14.1

Table 14.1

Waterproof Membrane Property Requirements

Property Standard Value

Elongation Film ASTM D638 Longituduial 210 %

Transverse 160 %

Tear resistance ASTM D1004 Longitudinal 340 MPa

Transverse 310 MPa

Adhesion to primed concrete ASTM D1000 1.8 MPa

Elongation compound ASTM D1000 1.8 MPa

Puncture resistance ASTM E154 220 N over 65 mm

Water resistance ASTM D570 After 24 h. 0.14 %

After 35 d 0.95 %

Environmental resistance ASTM D543

Moisture vapour transmission rate ASTM E96 0.3g/M2 24 h

Minimum thickness 1.0 mm.

14.3.4 Application

1 Waterproofing membranes placed on vertical concrete faces shall be protected by preformed

asphalt board.

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2 Boards shall be bonded onto position with high quality solvent borne contact adhesive based

on polychloroprene rubber.

3 The Contractor shall co-ordinate the installation of waterproofing membrane with floor drains,

equipment bases and other adjacent work and mask adjacent work to prevent soil marks.

4 Areas where waterproofing is applied shall be protected from all traffic and where necessary

backfilling. All damage to finished portions of the waterproofing membrane shall be either

repaired or replaced, or both, in a manner acceptable to the Engineer.

14.4 PENETRATIVE PRIMER

14.4.1 General

1 The system shall be a penetrating hydrophobic treatment that protects concrete from both

water and chloride intrusion, while permitting water vapour transmission.

2 The treatment shall significantly reduce the absorption of water and water borne salts but

allow the transmission of water vapour from the substrate.

3 The treatment shall not produce any discoloration of the substrate and shall have excellent

resistance to weathering.

14.4.2 Material

1 The material shall be a low viscosity silane-siloxane system which penetrates deeply into a

porous substrate and reacts to produce a bonded hydrophobic lining to the pores.

2 The material shall be resistant to petrol, oil, and atmospheric contaminants such as car

exhaust fumes and industrial exhausts.


1 The surface shall be dry, free from oil and grease, loose particles, decayed matter, algae

growth and curing compounds.

2 If the concrete surface is newly cast and has a very smooth finish, the surface shall be

roughened by sand or grit blasting, water blasting or some mechanical means. The Engineer

shall decide if this means of preparation is required.

3 Moss or algae growth on the surface shall be removed using a proprietary fungicidal wash in

accordance with the manufacturer’s recommendations.

4 Concrete finishing required shall be completed before the application of the treatment.

5 Cracks of width greater than 0.2 mm shall be filled in accordance with the manufacturer’s

recommendations.

14.4.4 Application

1 Unless directed otherwise by the Engineer the treatment shall be applied a minimum period

of 24 h after the wet curing period, and shall be surface dry.

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2 The Contractor shall carry out tests to verify the depth of penetration of the material. These

tests shall be carried out on specimens of the actual mix design and shall use coloured dyes

to trace the penetration of the material.

3 Where fine cracking has occurred in the concrete (at a width not greater than 0.3 mm for

reinforced concrete and 0.2 mm for water retaining structures) an additional four 'stripe coats'

of the treatment shall be applied before the main treatment.

4 The application of the material on surfaces shall be by a low pressure spray direct from the

can. Under no circumstances should thinning of the material be carried out.

5 The rate of application shall ensure that the surface is completely saturated. The

impregnated coating shall be applied to two or more flood coats each flood coat shall be a

minimum of 0.4 l/m2.

6 The material shall be applied strictly in accordance with the manufacturers instructions and

as follows:

(a) the material shall be applied by a fine nozzle spray

(b) application will not be permitted when the ambient air temperature is above 35 C or

in windy conditions

(c) the surface shall be cleaned by a stiff brush or compressed air to remove all loose

deposits

(d) concrete to be treated shall be surface dry for a minimum period of 24 h before

impregnation

(e) membranes, joint sealers and cast in concrete ancillaries shall be masked off before

treatment

(f) application shall be made by saturation flooding

(g) the interval between application shall be at least 6 h

(h) treated areas shall be protected from sea water and rain for 6 h after treatment.

14.5 PROTECTIVE COATING

14.5.1 General

1 The coating system shall be used for the protection of new or existing reinforced concrete

structures against carbonation or chloride induced corrosion.

2 The system shall comprise of a penetrating, reactive primer and an acrylic polymer top coat

system to minimise ingress of acidic gases, chlorides and water.


1 Before application, all surfaces must be dry and free from oil, grease, loose particles,

decayed matter, moss or algae growth and general curing compounds.

2 All such contamination and laitence must be removed by the use of grit blasting, high

pressure water jetting or equivalent mechanical means.

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3 Before proceeding to apply the protective coatings, all surfaces which are not to be coated

but which may be affected by the application of the coating shall be fully masked and, in

particular, flora and fauna shall be protected.

4 Blow holes and areas of pitting shall be made good with a one part modified cementitious

material and allowed to cure in accordance with the manufacturer's recommendations. In

particular, the application shall be in accordance with the manufacturer's recommendations,

with respect to the maximum application thickness.

14.5.3 Material

1 The materials are required to provide in-depth protection against carbonation and chloride

penetration whilst permitting water vapour transmission from the concrete.

2 The primer shall be a low viscosity silane-siloxane system which penetrates deeply into a

porous substrate and reacts to produce a bonded hydrophobic lining to the pores.

3 The material employed for the coating shall comply with the following requirements:

Wet film thickness 400 µm Dry film thickness 200 µm Carbon Dioxide diffusion resistance R Value at 325 microns > 161 metres. (Taywood Engineering Laboratories) Water vapour transmission (Taywood Engineering Laboratories) Shall be more than 13 g/m

2.d

Reduction in chloride ion penetration 94 % minimum at 28 d (BS 1881 : Part 124) Tear Resistance (ASTM D624) 7.3 kN/mm

2

Crack bridging (BRE Method) 5.1 mm Chloride Ion Diffusion (Taywood Engineering Labororatories) 3.63 x 10

-10 cm

2/sec.

4 Where test methods are not specified, the procedure for establishing compliance with the

above criteria shall be agreed with the Engineer.

5 The Contractor is required to adhere strictly to the manufacturer's recommendations

regarding the use, storage, application and safety rules in respect of the approved materials.

14.5.4 Application

1 Where required by the Engineer, trial areas not exposed in the finished work shall first be

treated using the selected materials. These trial areas shall be noted on the Drawings and

shall be carried out using the type of materials, mixing procedures and applications that will

be used on the contract and shall be approved by the Engineer before the Contractor

commences with the general work.

2 The exposed concrete surfaces as defined in the documents or as agreed with the Engineer

shall be conditioned by the application of a penetrating hydrophobic treatment. The primer

shall be allowed to dry in accordance with the manufacturer's requirements.

3 The Contractor shall then apply two coats of pigmented topcoat in accordance with the

manufacturer's instructions. The finished coating shall be pinhole free and have a total

minimum dry film thickness of 150 m. The colour and finish is to be as agreed with the

Engineer.

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4 The coating shall be applied by spray, roller or brush to achieve a finish acceptable to the

Engineer.

5 In all operations of storage, mixing and application the Contractor shall comply with the health

and safety recommendations of the manufacturer and governing authorities.

14.6 PLASTIC SHEET LINER FOR CONCRETE STRUCTURES

14.6.1 General

1 This Subpart covers the supply and installation of sheet liners in reinforced concrete

structures.

2 The liner must be continuous and free of pinholes both across the joints and in the liner itself.

3 All work for and in connection with the installation of the lining in concrete pipe and structure,

and the field sealing and welding of joints, will be done in strict conformity with all applicable

specifications, instructions, and recommendations of the lining manufacturer.

14.6.2 Shop Drawings and Submittals

1 The Contractor shall submit to the Engineer for approval the following:

(a) liner schedule

(b) material certifications

(c) test results

(d) material samples

(e) the manufacturer of the lining will submit an affidavit attesting to the successful use

of its material as a lining for sewer pipes and structures for a minimum period of

five years in service conditions recognised as corrosive or otherwise detrimental to

concrete.

14.6.3 Liner Material Requirements

1 The sheet liner shall be manufactured from, high molecular weight PVC or PE resin and

other components necessary to make a material of permanent flexibility suitable for a liner in

concrete pipes and structures in sewerage service. The weld strips and the joint strips shall

be made from like material. For PVC and PE sheet liners, the actual resin used in

manufacture must constitute not less than 99 % of the resin used in the formulation.

2 Copolymer resins will not be permitted.

3 All plastic sheets including locking extensions, all joints and welding strips shall be free of

cracks, asperities and other defects that may affect the protective properties of the material.

4 The properties of PVC and PE sheet are shown in Table 14.2

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Table 14.2

Properties of PVC and PE Sheet Liners

Property Test Method Requirement

PVC Elongation at break ASTM D638/882 300 % Tensile Strength ASTM D638/412 15 MPa Low Temp. Brittleness ASTM D746 0°C

PE Elongation at break ASTM D638/882 Exceeds 600 % Tensile Strength ASTM D638/412 10-20 MPa Low Temp. Brittleness ASTM D746 -75 °C

14.6.4 Plastic Sheet Liner Strip Properties

1 Except at shop welds, all plastic sheet liners and strips shall have the properties shown in

Table 14.3 when tested at 25 °C.

Table 14.3

Properties of Plastic Sheet Liner Strips

Property Requirement

Tensile strength 15 MPa

Elongation at break 200 %

Shore Durometer 1 s 50 - 60 5 (with respect to 10 s

35 - 50 5)

Weight change 1.5 %

14.6.5 Basic Sheet Dimensions

1 The minimum thickness of the material shall be as shown in Table 14.4

Table 14.4 Plastic Sheet Liner Minimum Dimensions

Material Thickness Structures

Sheet with locking extensions 4.0 mm

Sheet, plain 2.3 mm

Joint strip 1.9 mm

Weld strip 2.4 mm

14.6.6 Liner Details

1 Locking extensions (T-shaped) shall be of the same materials as that of the liner and shall be

integrally extruded with the sheet.

2 Locking extensions shall be approximately 65 mm apart and shall be at least 10 mm high.

3 Sheets not used for shop fabrication into larger sheets shall be shop tested for pinholes using

an electrical spark tester set at 9000 V per 1.0 mm thickness of lining minimum. Holes shall

be repaired and retested.

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14.6.7 Installation

1 Installation of the lining, including preheating of sheets in cold weather and the welding of all

joints, shall be performed in accordance with the recommendations of the manufacturer.

2 The lining to be held snugly in place against inner forms by means of steel banding straps or

other means recommended by the manufacturer.

3 Concrete that is to be poured against the lining shall be vibrated, spaded, or compacted in a

careful manner to protect the lining and produce a dense, homogenous concrete, securely

anchoring the locking extensions into the concrete.

4 In removing forms care shall be taken to protect the lining from damage. In particular:

(a) sharp instruments not to be used to pry forms from lined surfaces.

(b) when forms are removed, any nails that remain in the lining to be pulled, without

tearing the lining, and the resulting holes clearly marked.

(c) form tie holes to be marked before ties are broken off and all areas of serious

abrasion or damage shall be marked.

5 All nail and tie holes and all cut, torn, and seriously abraded areas in the lining shall be

patched as follows:

(a) patches made entirely with welding strip to be fused to the liner over the entire patch

area

(b) larger patches may consist of smooth liner sheet applied over the damaged area with

adhesive

(c) all edges must be covered with welding strip fused to the patch and the sound lining

adjoining the damaged area.

6 Hot joint compounds, such as coal tar, shall not be poured or applied to the lining.

7 The Contractor shall take all necessary measures to prevent damage to the installed lining

from equipment and materials used in or taken through the work.

14.6.8 Testing Requirements

1 Samples taken from sheets, joints or weld strips shall be tested to determine material

properties. Determination of tensile strength and elongation shall be in accordance with

ASTM D 412 using Die B. Determination of indentation hardness shall be in accordance with

ASTM D 2240 using a Type D Durometer, except that a single thickness of material and

indentation hardness shall be made on 25 mm by 75 mm specimens. Thickness of

specimens shall be the thickness of the sheet or strip.

2 The measurement of initial physical properties for tensile strength, weight, elongation and

indentation hardness shall be determined before chemical resistance tests.

3 Chemical resistance tests shall be carried out to determine the physical properties of the

specimens after exposure to chemical solutions. Test specimens shall be conditioned to

constant weight at 43 °C before and after submersion in the solutions detailed in Table 14.5

for a period of 112 d at 25 3 °C.

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4 Volumetric percentages of concentrated reagents of CP grade: At 28 day intervals,

specimens shall be removed from each chemical solution and tested. If any specimen fails to

meet the 112 day exposure, the material will be subject to rejection.

5 Pull test for locking extensions: Liner locking extensions embedded in concrete shall

withstand a test pull of at least 18 kN/m, applied perpendicularly to the concrete surface for a

period of 1 min, without rupture of the locking extensions or withdrawal from embedment.

This test shall be made at a temperature between 21 °C to 27 °C inclusive.

6 Shop-welded joints: Shop-welded joints, used to fuse individual sections of liner together,

shall be a least equal to the minimum requirements of the liner for thickness, corrosion

resistance and impermeability. Welds shall show no cracks or separations and shall be

tested for tensile strength. Tensile strength measured across the welded joint in accordance

with ASTM D 412 using Die B shall be at least 15 MPa. Test temperature shall be 25 3 C

and the measured minimum width and thickness of the reduced section shall be used.

7 Spark test: All liner shall be shop tested for holes with a spark tester set to provide from

15 000 to 20 000 V. Sheets having holes shall be satisfactorily repaired in the shop before

shipment from the manufacturer’s plant.

8 The Contractor shall provide the Engineer with certified copies of test reports before the

shipment of the product to the Site.

Table 14.5

Chemical Resistance Tests

Chemical Solutions Concentration

Sulphuric Acid 20 %

Sodium Hydroxide 5 %

Ammonium Hydroxide 5 %

Nitric Acid 1 %

Ferric Chloride 1 %

Soap 0.1 %

Detergent (Linear alkyl benzyl sulphonate or LAS) 0.1 %

Bacteriological BOD not less than 700 mg/l

Phosphoric Acid 50 %

14.6.9 Special Requirements

1 Liner sheets to be closely fitted and properly secured to the inner forms.

(a) sheets that are to be cut to fit curved and warped surfaces shall use a minimum

number of separate pieces

(b) a 50 mm wide water resistant tape or welding strip shall be welded on the back of butt

joints to prevent wet concrete from flowing around the edges.

2 Unless otherwise shown on the Drawings, the lining will be returned at least 75 mm at the

surfaces of contact between the concrete structure and items not of concrete and

(a) the same procedure will be followed at joints where the type of protective lining is

changed or the new work is built to join existing unlined concrete

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(b) at each return, the returned liner will be sealed to the item in contact with the plastic

lined concrete with an adhesive system

(c) if the liner cannot be sealed with this adhesive because of the joint at the return being

too wide or rough or because of safety regulations, the joint space shall be densely

caulked with lead wool or other approved caulking material to a depth of 50 mm and

finish with a minimum of 25 mm of an approved corrosion resistant material.

14.6.10 Joints in Lining for In-Situ Concrete Structures

1 Field joints and Lining at joints shall be free of all mortar and other foreign material and shall

be clean and dry before joints are made.

2 All welding is to be in strict conformance with the specifications of the lining manufacturer.

14.6.11 Testing and repairing damaged surfaces

1 All surfaces covered with lining, including welds, will be tested with an approved electrical

holiday detector with the instrument set at 9000 V per 1.0 mm of lining minimum:

(a) all welds shall be physically tested by a non-destructive probing method

(b) all patches over holes, or repairs to the liner wherever damage has occurred.

2 Each transverse welding strip which extends to a lower edge of the liner will be tested by an

approved testing agency at the cost of the Contractor.

(a) the welding strips will extend 50 mm below the liner to provide a tab.

(b) a 5 kg pull will be applied to each tab. The force will be applied normal to the face of

the structure by means of a spring balance

(c) liner adjoining the welding strip will be held against the concrete during application of

the force

(d) the 5 kg pull will be maintained if a weld failure develops until no further separation

occurs.

(e) defective welds will be retested after repairs have been made

(f) tabs shall be trimmed away neatly by the installer of the liner after the welding strip has

passed inspection.

(g) inspection will be made within two days after joints has been completed in order to

prevent tearing the projecting weld strip and consequent damage to the liner from

equipment and materials used in or taken through the work.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 15: Hot Weather Concreting

15 HOT WEATHER CONCRETING ............................................................................. 2

15.1 GENERAL ............................................................................................................... 2

15.1.1 Scope 2

15.1.2 References 2

15.1.3 Definition of Hot Weather 2

15.1.4 System Description 3

15.1.5 Submittals 3

15.2 PLACING TEMPERATURE ..................................................................................... 3

15.3 PLANNING CONCRETING ..................................................................................... 4

15.4 MIX DESIGN ........................................................................................................... 4

15.5 TEMPERATURE CONTROL ................................................................................... 4

15.5.1 General 4

15.5.2 Aggregates 4

15.5.3 Water 5

15.5.4 Cement 5

15.5.5 Addition of Ice 5

15.5.6 Liquid Nitrogen 6

15.6 BATCHING AND MIXING ........................................................................................ 6

15.7 TRANSPORTATION ............................................................................................... 6

15.8 PLACING AND FINISHING ..................................................................................... 6

15.9 CURING AND PROTECTION .................................................................................. 7

15.10 INSPECTION AND TESTING .................................................................................. 7

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15 HOT WEATHER CONCRETING

15.1 GENERAL

15.1.1 Scope

1 This Part covers the precautions to be taken for hot weather concreting for all structural

concrete except blinding concrete, where a minimum compressive strength is specified.


This Section



Part 8 .............. Transportation and Placing of Concrete

Part 10 ............. Curing

15.1.2 References

ACI 305R-91 ............... American Concrete Institute , Hot Weather Concreting

ASTM C1064 .............. Measuring the Temperature of Concrete

BS EN 1992-1-1 ......... Eurocode 2, Design of concrete structures. General rules and rules for

buildings

BS EN 480 .................. Admixtures for concrete, mortar and grout. Test methods

BS EN 934 .................. Admixtures for concrete, mortar and grout

15.1.3 Definition of Hot Weather

1 The requirements of the following clauses of the specification are applicable during the hot

weather period in Qatar.

2 The hot weather period shall be defined as starting when the maximum ambient air shade

temperature on the Site exceeds 35 C for three consecutive days. The end of the hot

weather period shall be defined as the period when the maximum air shade temperature is

below 35 C on three consecutive days.

3 The Contractor shall establish a thermometer on Site that records the ambient air shade

temperature. The thermometer shall be established at a position to provide representative air

temperature for the Site conditions. If requested by the Engineer the Contractor shall arrange

for the calibration of the Site thermometer.

4 Hot Weather” shall mean any combination of the following conditions that tends to impair the

quality of freshly mixed or hardened concrete by accelerating the rate of moisture loss and

rate of cement hydration, or otherwise causing detrimental results such as:

(a) High ambient temperature (when the shade temperature is above 40 deg C on a rising

thermometer, 43 deg C on a falling thermometer),

(b) High concrete temperature,

(c) Low relative humidity,

(d) High wind speed

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(e) the rate of evaporation exceeds 0.75 kg/m2/h

15.1.4 System Description

1 The Contractor shall undertake hot weather concreting procedures that are effective in

controlling the following potential problems associated with concreting in hot weather:

(a) increased water demand of the mix

(b) increased rate of slump loss

(c) increased rate of setting

(d) increased tendency for plastic shrinkage cracking

(e) decreased long-term strength

(f) increase tendency for drying shrinkage and cracking

(g) increased tendency for differential thermal effects with consequent cracking

(h) decreased durability from cracking where there is increased permeability.

15.1.5 Submittals

1 The Contractor shall prepare weekly in advance his proposed concreting programme

showing the quantities to be placed and the anticipated placing hours.

2 At least one month before the start of the hot weather period the Contractor shall submit his

specific proposals for the control of the concrete temperature for the constituent materials;

cement, water aggregates.

3 Where required the Contractor shall submit to the Engineer his proposals for the use of liquid

nitrogen for cooling which shall include details of previous project application and the

intended methods to be used and quantities of liquid nitrogen.

15.2 PLACING TEMPERATURE

1 This Subpart of the specification applies at all times of the year and at all times of the day.

2 Maximum fresh concrete temperature (at placement) shall not exceed 32°C unless

construction testing to verify a proposed concrete mixture will function satisfactorily at a

concrete temperature greater than 32°C. No concrete shall be placed if the concrete

temperature is above 35°C

3 Concrete shall not be placed if the shade temperature exceeds 40ºC.

4 The temperature of each truck of concrete shall be measured using either a glass, dial type

or electronic thermometer, just before the placing of the concrete and the temperature

recorded on the delivery ticket. The maximum temperature at placing shall apply to the entire

load of concrete in the truck or conveyer.

5 The Contractor shall allow for the increase in concrete temperature in the period from

dispatch from the plant while in transportation or whilst awaiting placement on Site and take

adequate measures to ensure the maximum temperature is not exceeded.

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15.3 PLANNING CONCRETING

1 During the hot weather period as defined in Clause 15.1.3 of this Part, the Contractor shall

plan concreting operations such that no concreting takes place between the hours of

10:00 hours and 17:00 hours.

2 The Contractor shall arrange concrete pours such that the programme of works can be

achieved without concreting during the period from 10:00 hours to 17:00 hours.

3 The Contractor shall nominate one member of his staff to be the co-ordinator for the supply

of concrete. The co-ordinator’s responsibilities shall include ensuring the batched rate

matches that of delivery and placement and the preparations needed before commencing a

concrete pour.

15.4 MIX DESIGN

1 In the hot weather period, the Contractor shall review all concrete mix designs to ensure that

the design slump or workability specified is achieved without increase in the mix water

content. The Contractor shall make modifications to the mix design to allow for increased

slump loss during transportation in hot weather.

2 This shall be achieved by adjusting the proportion of admixture, plasticiser or super

plasticiser. The permitted range of admixture shall be clearly stated on the concrete mix

design with nominal values for cold weather and hot weather use.

3 Under no circumstances will the addition of extra water that increases the water cement ratio

be permitted during hotter weather.

4 All concrete materials and proportions used in periods of hot weather shall be those that have

a satisfactory record of use in such conditions.

15.5 TEMPERATURE CONTROL

15.5.1 General

1 The Contractor’s specific proposals for the control of the concrete temperature shall include

extent and type of shading of aggregates, method of chilling mix water and procedures for

batching and mixing, transportation, placing and finishing, curing and protection.

2 These shall include calculations in accordance with ACI 305R, clause 3.1 “estimating

concrete temperature”. The Contractor shall calculate the temperature of freshly produced

concrete based on the input temperatures of the constituent materials and the weights from

particular mix designs. The calculations shall make allowance for the rise in temperature

between mixing and placing due to the transportation and waiting period. The calculations

shall successfully demonstrate that the temperature can be maintained below 32 C at the

point of placing.

15.5.2 Aggregates

1 All practical means shall be employed to keep the aggregates as cool as possible.

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2 Stockpiles of aggregates shall be shaded from direct sunlight. Shades shall extend beyond

the edge of aggregate storage areas and stockpile layouts shall be such that direct sunlight is

not incident on the aggregates. Shades shall be constructed to allow access for mechanical

shovels or means of conveyance. Shades and stockpiles shall be constructed so as to permit

the free flow of air over the aggregates. Embedded cooling pipes may also be used to cool

the aggregate.

3 Sprinkling of coarse aggregates to reduce temperature by evaporation or direct cooling shall

not be permitted.

15.5.3 Water

1 Mix Water shall be cooled by storing in underground tanks or insulated tanks above ground.

2 The water shall be chilled by the use of proprietary chillers or the addition of ice to the water

tank. Measures shall be taken to ensure that ice pieces are not inadvertently deposited

directly into the mixer.

3 Water shall not be chilled below a temperature of 5 C.

4 Tanks, pipes or trucks used for the storage or transportation of water shall be insulated and

painted white.

5 The mechanical refrigeration equipment and insulated water storage shall be adequate for

the anticipated hourly and daily production rates of concrete during the hot weather period.

6 Mixing water may also be chilled by injection of liquid nitrogen into an insulated holding tank,

such procedures shall be to the approval of the Engineer.

7 Ice shall be completely melted in mixing water prior to adding water to the mixer.

15.5.4 Cement

1 The use of freshly ground cement at very high temperatures is not permitted.

2 The cement shall be kept below the temperature which there is a tendency of false set.

3 Under no conditions shall the temperature of the cement exceed 75 C when it enters the

mixture.

4 The Contractor shall make arrangements for storage on Site to allow cooling of freshly

ground and delivered cement.

15.5.5 Addition of Ice

1 Crushed shaved or chipped ice can be used as part of the mixing water for reducing the

concrete temperature.

2 The maximum nominal size of ice particles shall be 10 mm and all the ice must be melted

before the completion of mixing of the concrete in the pan.

3 To ensure proper concrete mixing the maximum proportion by substitution shall be 75 % of

the batch water requirement.

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4 Crushed ice shall be stored at a temperature that will prevent lumps from forming by

refreezing of particles.

5 The batching plant shall incorporate a mechanical system for correctly proportioning and

weighing the ice to be added to the mixture.

6 The quantity of ice shall be deducted from the total batch water.

7 The Contractor shall ensure there are adequate quantities of ice in suitable refrigerated

storage on the Site at the plant to meet the anticipated daily and hourly production rates of

concrete during the hot weather period.

15.5.6 Liquid Nitrogen

1 Freshly mixed concrete maybe cooled by the injection of liquid nitrogen.

2 Care shall be taken to ensure that the concrete directly adjacent the injection nozzle is not

frozen.

3 The use of liquid nitrogen for cooling concrete shall include a nitrogen supply vessel and

injection facility for the batching plant or one or more injection stations for truck mixers.

4 The system may be set up at the Site for injection just before placing.

5 Proper safety precautions as advised by the supplier of the liquid nitrogen shall be used.

15.6 BATCHING AND MIXING

1 The drums of concrete mixer trucks shall be painted white to minimise solar heat gain.

2 Where a truck mixer has been left standing in the sun, the empty drum shall be sprayed with

water and the drum flushed out with cold water before batching. Care shall be taken to

ensure all water is removed from the drum before batching.

3 The temperature of the concrete shall be checked after discharge from the mixer and written

on the delivery ticket. Temperature check shall be carried out at the plant on the concrete

floor for every 50 m3 produced or every hour which ever is the minimum.

4 A water-reducing, set-retarding chemical admixture conforming to the requirements of BS EN

480 Parts 1, 2 and 4 may be used in varying proportions under different air temperature

conditions.

15.7 TRANSPORTATION

1 The transportation, placing, compaction and finishing of concrete shall be at the fastest

possible rate. Delivery of concrete to the Site shall be properly scheduled to match the rate of

placement and compaction.

15.8 PLACING AND FINISHING

1 If the temperature of the first truck of concrete of a particular pour is above the specification

maximum temperature limit then placing shall not commence.

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2 If a pour is in progress and the temperature of a particular truck exceeds the maximum

permitted temperature the placing may be allowed to continue at the discretion of the

Engineer in order to avoid the possible development of a cold joint.

3 However, no further concreting pours shall take place until the Contractor has submitted

revised calculations, in accordance with ACI 305R clause 3.1 to demonstrate that the

maximum temperature will not be exceeded in the future. Before beginning new pours the

temperature of the concrete constituent materials shall be monitored to verify that they meet

the assumptions of the calculations.

15.9 CURING AND PROTECTION

1 Curing and protection shall conform to the requirements of Part 10 of this Section.

2 Evaporation shall be minimised, particularly during the first few hours subsequent to placing

concrete, by suitable means such as applying moisture by fog spraying or any other means

acceptable to the Engineer.

15.10 INSPECTION AND TESTING

1 All thermometers used for the measurement of concrete temperature shall be calibrated

weekly against a glass mercury thermometer. Calibration shall be carried out over the

temperature range of 10 C to 100 C using a water bath with ice or heating.

2 The method used to determine acceptance of temperature controlled concrete should be in

accordance with ASTM C1064.

3 All concrete test specimens for strength or other purposes shall be carefully protected and

cured.

4 Specimens shall be protected from accidental damage by plant personnel or equipment on

Site.

5 Specimens shall be kept moist by the addition of water or covering by suitable curing

materials.

6 The exact time of preparation of the specimen on Site shall be noted and the time when it is

transferred to the laboratory. These times shall be written on the test report.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 16: Miscellaneous

16 MISCELLANEOUS .................................................................................................. 2

16.1 GENERAL ............................................................................................................... 2

16.1.1 Scope 2

16.1.2 References 2

16.2 PAVEMENT QUALITY CONCRETE ........................................................................ 3

16.2.1 Scope 3

16.2.2 Mix Designs 3

16.2.3 Cement 4

16.2.4 Water 4

16.2.5 Aggregates 5

16.2.6 Admixtures 5

16.2.7 Air content 5

16.2.8 Density 5

16.3 CEMENTITIOUS GROUT ........................................................................................ 6

16.3.1 General 6

16.3.2 Material 6

16.3.3 Workmanship 6

16.4 SCREEDS ............................................................................................................... 7

16.4.1 Scope 7

16.4.2 General 7

16.5 CELLULAR CONCRETE ......................................................................................... 9

16.6 REPAIR OF CONCRETE ........................................................................................ 9

16.6.1 General 9

16.6.2 Honeycombing or Spalling 9

16.6.3 Crack injection 11

16.7 POLYESTER RESIN CONCRETE (PRC) - PIPING SYSTEMS FOR NON-

PRESSURE DRAINAGE AND SEWERAGE ......................................................... 13

16.7.1 General 13

16.7.2 Resin 13

16.7.3 Minimum strength 14

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16 MISCELLANEOUS

16.1 GENERAL

16.1.1 Scope

1 This Part deals with miscellaneous items related to concrete works including pavement

quality concrete, no fines concrete, lightweight concrete, cementitious grout, screeds, repair

of concrete and guniting.


This Section

Part 2, .............. Aggregate

Part 3, .............. Cementitious Material

Part 4, .............. Water

Part 5, .............. Admixture



Part 8, .............. Transportation and Placing of Concrete

Part 9, .............. Formwork

Part 10, ............ Curing

Part 15, ............ Hot Weather Concreting.

16.1.2 References


ACI 506, ..................... Guide to Shotcrete

ASTM C989 –10, ........ Standard Specification for Slag Cement for Use in Concrete and

Mortars

BS 146, ....................... Portland-blast furnace cement

BS 812, ....................... Testing aggregates

BS 1881, ..................... Testing concrete

BS 2782, ..................... Methods of testing plastics

BS 3892, ..................... Pulverised fuel ash

BS 4551, ..................... Methods of testing mortars, screeds and plasters

BS 5075, ..................... Concrete admixtures

BS 6319, ..................... Testing of resin and polymer / cement compositions for use in

construction

BS 6610, ..................... Specification for pozzolanic pulverised-fuel ash cement.

BS 8203, ..................... Code of practice for installation of resilient floor coverings.

BS 8500, ..................... Concrete

BS EN 197-1, ............. Cement. Composition, specifications and conformity criteria for

common cements

BS EN 480, ................. Admixtures for concrete, mortar and grout. Test methods (parts: 1, 2,

4, 5, 6, 8, 10, 11, and 12)

BS EN 934, ................. Admixtures for concrete, mortar and grout (parts: 2, 6)

BS EN 998, ................. Specification for mortar for masonry

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BS EN 1744-1, ........... Tests for chemical properties of aggregates. Chemical analysis

BS EN 12350, ............. Testing fresh concrete

BS EN 12390-5, ......... Flexural strength of test specimens

BS EN 12620, ............. Aggregates for concrete

EN 197-4:2004 ........... Cement. Composition, specifications and conformity criteria for low


EN 197-4, ................... Cement. Composition, specifications and conformity criteria for low


EN 12350, .................. Testing fresh concrete

EN 1744-1, ................. Tests for chemical properties of aggregates. Chemical analysis

GSO EN 206-1, .......... Concrete Specification, performance, production and conformity

SHW 1000 .................. Specification for Highway Works – UK ROAD PAVEMENTS –

CONCRETE MATERIALS

16.2 PAVEMENT QUALITY CONCRETE

16.2.1 Scope

1 This Subpart covers the mix design for concrete used for aircraft aprons and roadworks as

surface slabs, continuously reinforced concrete roadbase, and wet lean mix except cement

bound granular material used as a roadbase or sub-base or as a backfill material for

excavations.

16.2.2 Mix Designs

1 Concrete in rigid or composite pavements shall be one of the grades given in Table 16.1

below, in accordance, with the pavement design shown on the Drawings or as directed by the

Engineer.

2 All concrete for use in pavements shall be designed mixes or equivalent standard mixes in

accordance with the relevant clauses of BS 8500 and GSO EN 206-1, except where

otherwise specified.

3 Prescribed mixes may be used for rapid construction with the approval of the Engineer.

Table 16.1

Pavement Grades

Pavement Layer

BS 8500 and

GSO EN 206-

1Designed

Mix

BS 8500 and

GSO EN 206-1

Standard Mix

Surface Slabs

Unreinforced Concrete C40

Jointed Reinforced Concrete ( JRC ) C40

Continuously Reinforced Concrete Pavement ( CRCP ) C40

Continuously Reinforced Concrete Roadbase ( CRCR ) C40

Ground Anchorage Beam C40

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Pavement Layer

BS 8500 and

GSO EN 206-

1Designed

Mix

BS 8500 and

GSO EN 206-1

Standard Mix

Wet Lean Mix Concrete 4 C20 ST4



Wet Lean Mix Concrete 1 C7.5 ST1

16.2.3 Cement

1 The general term 'cement' in this Part means the materials shown below.

Cement Complying with

Cement. Composition, specifications and conformity criteria for common cements

EN 197-1

Portland blast furnace cement BS 146 or EN 197-4

Specification for pozzolanic pulverised-fuel ash cement (grades C20 or below)

BS 6610

2 The use of a combination of Portland cement and ground granulated blast furnace slag is

permitted subject to the approval of the Engineer. In such cases, the Engineer will stipulate

the minimum combined cementitious material content required for the mix.

3 The use of a combination of Portland cement and pulverised fuel ash (PFA) is permitted

subject to the approval of the Engineer. In such cases, the Engineer will stipulate the

minimum combined cementitious material content required for the mix. PFA shall be in


4 The use of microsilica in the mix designs will be permitted if approved by the Engineer.

5 The Engineer will stipulate the minimum combined cementitious material content required for

the mix where PFA or GGBFS are used.

6 The maximum proportion of ground granulated blastfurnace slag with Portland cement shall

be as per Table 6.6 of Part 5.6.

7 In combination with Portland cement, the proportion of PFA by mass to the total cement shall

be as per Table 6.6 of Part 5.6.

8 The limit of chloride content of the concrete shall be as stated in Table 6.5 of Part 5.6.

9 The minimum cement content for concrete pavements shall be preapproved by Qatar

Standards.

16.2.4 Water

1 Water for use in the making and curing of concrete shall conform to the requirements of Part

4 of this Section.

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2 The water content shall be the minimum required to provide the agreed workability for full

compaction of the concrete to the required density, as determined by trial mixes or other

means approved by the Engineer..

16.2.5 Aggregates

1 The requirements of Part 2 of this specification will govern, except as modified below.

2 Aggregates for all pavement concrete shall be complying with BS EN 12620

3 Alternatively coarse aggregate of recycled and secondary aggregate materials may be used

to replace up to 50% by mass of coarse aggregate

4 The nominal size of coarse aggregate shall not exceed 40 mm. When the spacing between

longitudinal reinforcement is less than 90 mm, the nominal size of coarse aggregate shall not

exceed 20 mm.

5 If requested by the Engineer, the Contractor shall carry out tests on the proposed aggregate

combination to check for the possibility of alkali silica reaction. Such tests shall be carried out

in accordance with the procedure laid down in Part 2 of this Section.

16.2.6 Admixtures

1 Plasticisers or water reducing admixtures shall comply with BS 5075, BS EN 480 and BS EN

934. Admixtures containing calcium chloride shall not be used.

2 Other chloride-free admixtures may be used with the approval of the Engineer.

16.2.7 Air content

1 The total quantity of air in air-entrained concrete as a percentage of the volume of the mix

shall be 5 1.5 % for mixes of nominal aggregate size 20 and be 4 1.5 % for mixes of

nominal aggregate size 40.

2 The air content shall be determined at the point of delivery by a pressure type air meter in

accordance with BS EN 12350-7, at the rate of one determination per 300 m2 of slab or at

least six times per day whichever is the greater, in conjunction with tests for workability and

strength. For areas less than 300 m2, the rate shall be at least one determination to each 20

m length of slab or less constructed at one time or at least three times per day. If the air

content is outside the specified limits, a further determination shall be made immediately on

the next available load of concrete before discharging. If the air content is still outside the

limit, the Contractor shall immediately adjust the air content of the concrete to improve its

uniformity, before further concrete is used in the Works.

3 The air-entraining agent shall be added at the mixer, by an apparatus capable of dispensing

the correct dose within the tolerance for admixtures given in EN 206-1, and so as to ensure

uniform distribution of the agent throughout the batch during mixing.

16.2.8 Density

1 The density of concrete Grades greater than C30 shall be such that without air-entrainment

the total air voids are not more than 3 %. With air entrainment, the total air voids shall be not

more than 8 %, for 20 mm aggregate or 7 % for 40 mm aggregate.

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2 The density of concrete Grades B15 and B20, mix ST4 or below shall be at least 95 %, of the

theoretical maximum dry density.

16.3 CEMENTITIOUS GROUT

16.3.1 General

1 This Subpart covers a general purpose non-shrink cementitious grout. The grout shall be

used to where it is necessary to eliminate shrinkage when filling the void between a base

plate and a substrate such as in the grouting of stanchion bases, anchorage fixings, including

masts, anchor bolts and fence posts.

2 The grout shall be supplied by a reputable construction chemical company as a single pack

prepackaged cement based product which is chloride free.

3 For a particular application, the Contractor shall submit a method statement detailing how the

formwork will be placed and the points where the grout will be poured.

4 Before beginning work on large repetitive works, the Contractor shall arrange for a site trial of

the materials and methods with the suppliers representative being present to train the

Contractor’s personnel in the correct use of the material.

16.3.2 Material

1 The grout shall be suitable for filling gaps of thickness up to 100 mm and shall be free flowing

and non shrink.

2 Positive volumetric expansion shall take place while the grout is plastic by means of gaseous

expansion to avoid shrinkage and cracking.

3 The compressive strength of the grout when tested in accordance with BS EN 12390-3 shall

be a minimum of 25 MPa at 24 h, 40 MPa at 7 d and 50 MPa at 28 d.

4 The grout shall exhibit a high early strength gain yet not be subject to cracking or other

detrimental effects.

5 At ambient temperatures above 35 C, cool water shall be used for mixing the grout before

placing.

16.3.3 Workmanship

1 The storage handling and pouring of the grout shall be in strict accordance with the

manufacturer’s instructions.

2 The substrate surface shall be free from oil grease or loose or partially bonded material.

3 If the concrete surface is defective or has laitance it shall be cut back to a sound base.

4 Bolt holes and fixing pockets shall be blown clean of dirt or debris.

5 The substrate shall be soaked with fresh potable water before grouting, although immediately

before grouting, free water shall be removed and blown out of bolt holes or pockets.

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6 Grout shall not be placed in a gap of less than 25 mm for base plates larger than 1 m wide.

For larger base plates or flow areas the manufacturers instructions shall be followed.

7 Base plates and metallic items shall be clean and free from oil, grease, or scale.

8 Vent holes shall be provided to allow the release of air from isolated spots.

9 Formwork shall be made leak proof by the use of form rubber strip or mastic sealant between

the constructive formwork and joints. Formwork shall extend above the required pour height

and if necessary shall be extended to allow a hydrostatic head to aid placement.

10 The grout shall be mixed mechanically with a slow speed drill fitted with a high-shear mixer.

11 The quantity of water to be added to the preweighed bags shall be enough to give the

desirable consistency as trowelable or flowable.

12 Mixing shall take place for a minimum of 5 min.

13 The grout shall be placed within the time limit specified by the manufacturer depending on

the actual application temperature.

14 Grout shall be poured from one side and it shall be verified that the grout has flowed under all

of the base plate with no voids. Pouring from several sides shall not be permitted.

15 Exposed areas of grout shall be thoroughly cured in accordance with Part 10 of this Section.

16.4 SCREEDS

16.4.1 Scope

1 This Subpart covers screeds that provide by means of a layer of mortar a level surface in

flooring applications and to provide falls on flat concrete roofs.

16.4.2 General

1 Screeds shall be suitable for application onto a concrete substrate.

2 The screeds shall be suitable for receiving surface finishes which may arrange from thin

flexible sheeting to ceramic tiling. The screed is not intended to be the final wearing surface.

3 Screed mortars shall generally comprise sand and cement modified by additives or

substituted by other materials such as polymers in order to provide specific performance

requirements.

4 For screeds of thickness greater than 40 mm it is permissible to incorporate a proportion of

10 mm aggregate.

5 Aggregates used for screeds shall not contain deleterious materials such as coal or iron

particles which may affect the finish the surface of the screed.

6 Admixtures for mortar screeds shall assist workability or alter rates of setting and hardening

and shall comply with the appropriate part of BS EN 480 and BS EN 934.

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7 Polymer based additives may be used to improve adhesion and strength of thin or featured

screeds, these shall be based on polyvinyl acetate (PVA) styrene bituene rubber (SPR) or

acrylic polymers.

8 Ready to use sand cement screeds shall comply with the material requirements BS EN 998.

9 Screeds with a rapid drying time to enable earlier floor finishes to be applied shall be used

strictly in accordance with the manufacturers’ instructions.

10 The interface of the screed in the concrete substrate shall be specified as one of the

following options by the Engineer:

(a) Monolithic with the concrete base: The screed shall be applied within 3 hours of

placing the concrete base.

(b) Bonded to the concrete base: Screed shall be laid onto a concrete base which is

hardened and is subsequently been prepared to receive the screed, the minimum

thickness of the screed shall be 25 mm and the maximum thickness 40 mm.

(c) As an unbonded screed: The screed shall be laid on a separating layer.

(d) As a floating screed: The screed shall be laid on an insulating material.

11 The cement and sand screed mix shall have the minimum amount of water added to give

sufficient workability and allow the material to be thoroughly compacted.

12 Pan type mixes shall be used to ensure efficient mixing of materials, the cement to aggregate

ratio shall be between 1 to 3 and 1 to 4.5 by weight. The mixing of the sand cement, water

and admixtures shall ensure a thorough homogeneous mixture with no balling up of the

cement.

13 Screeds shall be laid either between carefully levelled and trued batons or between strips of

screed laid and compacted to a finished level.

14 For bonded screed where a high degree of bond is required the surface laitance of the

concrete base shall be mechanically removed to expose the coarse aggregate. A thin layer

of neat cement grout shall be applied to the prewetted or dampened concrete and the screed

applied and compacted while the grout is wet.

15 Screeds shall be fully compacted by heavy hand or mechanical tamping. The screed at joints

around the perimeter shall be particularly well compacted to avoid breaking out and curling.

16 Screeds thicker than 50 mm shall be laid in two approximately equal layers; screed shall be

kept protected by waterproof sheeting for at least 7 days after laying.

17 Sheet and non ceramic tiling finishes shall only be applied after the screed has cured and

necessary strength achieved.

18 If requested by the Engineer the Contractor shall carry out a soundness and impact test in


19 Screeds shall be laid in bays of a size to minimise thermal moisture contraction. Contraction

or movement joints shall be provided as appropriate, where shown on the drawings or as

directed by the Engineer. Bays shall be laid alternatively.

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20 Bay sizes shall be approximately 15 m2 for 100 mm thick screed and 12 m2 for 75 mm thick

screed.

16.5 CELLULAR CONCRETE

1 Cellular Concrete (CC) is conventional concrete, where natural aggregate (gravel) is

exchanged for an insulation medium, namely air, embedded in an organic and bio-

degradable foam. It behaves, like conventional concrete, in particular concerning curing,

hardening and most important "ageing ". CC infinitely increases its strength by hydration as

long as exposed to humidity in the atmosphere.

2 CC offer more thermal insulation and a substantially higher fire-rating than conventional

concrete.

3 Minimum compressive strengths shall be 4.0 MPa.

4 The required density and strength of the CC shall be specified on the drawings and approved

by the Engineer.

5 The method of production of Cellular Concrete shall be shown on the drawings or directed by

the Engineer. The Contractor shall submit full technical details of the materials and method of

production for the CC along with a list of previous projects where the particular system has

been used.

6 After source approval of the material and system the Contractor shall submit a mix design for

the CLC for the approval of the Engineer. After the review and approval of the mix theoretical

mix design the Contractor shall carry out a trial mix to check the workability of the fresh

concrete and to allow samples to be made for compressive strength and density.

7 The Engineer may also instruct that tests are carried out for abrasion resistance and thermal

insulation properties.

8 Cellular Concrete shall not be used for structural reinforced members.

16.6 REPAIR OF CONCRETE

16.6.1 General

1 The extent and nature of the defects in concrete shall be established in accordance with Part

15 of this Section. Based on these results the Engineer shall confirm the acceptability of the

work and whether remedial works are required.

2 If remedial works are required the Contractor shall submit a detailed method statement

identifying the specific materials to be used and the sequence of activities for the repair.

3 Only proprietary proven materials that form part of a standard repair system shall be used.

16.6.2 Honeycombing or Spalling

1 Where there is honeycombed concrete or concrete damaged by physical forces such as

impact that has caused spalling, the concrete shall be replaced using a high strength free

flowing cementitious micro-concrete.

2 The areas of repair shall be marked out and agreed with the Engineer.

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3 All honeycombed, loose, cracked or friable concrete in these areas shall be removed until

sound concrete is reached. Due account shall be taken of propping or other instructions

given by the Engineer regarding sequences of removal and repair.

4 The equipment and methods used to break out the concrete shall be such that no reinforcing

steel or other embedded items such as conduits, lifting sockets, or other inserts are loosened

or damaged unless so directed by the Engineer.

5 Where the removal of concrete by mechanical means is difficult due to reinforcement

congestion, then the use of high pressure water jetting shall be considered and necessary

provisions for protecting the rest of the structure shall be made.

6 The prepared void shall be profiled so that entrapment of air is avoided during the repair

process using fluid micro-concrete.

7 The minimum depth of repair shall be 40 mm throughout. The perimeter of the area to be

repaired shall first be cut to a depth of 10 mm using a suitable tool. Feather edges will not be

accepted.

8 The prepared concrete surface shall be sound and clean and free of loose particles, dust and

debris.

9 Where exposed reinforcement is sound, it shall be mechanically cleaned of rust and loose

millscale.

10 Reinforcement damaged during the removal of concrete or the preparation process shall, if

required by the Engineer, be repaired or replaced.

11 Adequate formwork shall be provided in accordance with of Part 9 of this Section. This shall

be securely fixed to withstand the hydraulic pressures of the fluid micro-concrete repair

material without distortion or movement during placement.

12 The formwork shall be watertight at all joints between panels and between the formwork and

the existing concrete surface so as to prevent grout leakage.

13 The formwork shall be constructed from appropriate materials as agreed with the Engineer to

achieve the required finish.

14 Formwork surfaces that are to be in contact with the repair micro-concrete shall be treated

with a suitable mould release agent. This shall be used in accordance with the

manufacturer's recommendations.

15 The entry point of the feed pipe into the form shall be at the lowest point of the void. Sufficient

hydrostatic head or pumping pressure shall be maintained to ensure that the void is filled

completely and no air remains entrapped.

16 Where necessary, provision shall be made for controllable bleed points to prevent air

entrapment and enable the extent of flow of the repair material to be assessed.

17 The formwork shall be inspected by the Engineer and, if approved, filled with clean water

which demonstrates that the formwork is grout-tight and saturates the prepared concrete

surfaces. The formwork shall be then be completely drained and resealed

18 In situations where the completed repair will be subjected to constant immersion an epoxy

bonding agent shall be applied in accordance with the manufacturers’ instructions.

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19 Both the Compressive strength and Flexural strength shall be at a water:powder ratio of 0.18

and tested at 20 oC

20 The thermal conductivity and the elastic modulus of the repair material shall be compatible

with the host concrete.

21 If requested by the Engineer, recent test results of the material for the following properties

shall be submitted:

(a) thermal conductivity

(b) elastic modulus, BS 1881

(c) expansion characteristics, ASTM C 827, CRD 621-82A

(d) flow characteristic, UK DOT BD 27/86 paragraph 4.6 B.

22 The micro-concrete shall be mixed and placed in accordance with the manufacturer's

recommendations, particularly with regard to water content, mixing equipment and placing

time.

23 As far as possible the placing of the micro-concrete shall be continuous. The mixing

operation shall be timed so that there is minimal interruption in the material flow. If, however,

placing is interrupted, the operation shall recommence as soon as possible while the repair

material retains its flow characteristics.

24 The formwork shall not be removed until the repair micro-concrete has achieved a

compressive strength of at least 10 MPa or as directed by the Engineer.

25 Immediately after removal of the formwork the repair area shall be cured in accordance with

Part 10 of this Section.

26 The repair material shall:

(a) be shrinkage compensated in both liquid and cured states

(b) contain no metallic expansion system

(c) be prepacked and factory quality controlled

(d) be a free-flowing cementitious material that has a coefficient of thermal expansion fully

compatible with the host concrete and which complies with the requirements of Table

16.3.

Table 16.3

Property requirements of micro concrete

Property Test Method Minimum Value

Compressive strength BS EN 12390-3 @ 28 d 50 MPa

Flexural strength BS 4551 @ 28 d 10 MPa

Anchorage bond BS 8110 Passes

16.6.3 Crack injection

1 This clause of the specification covers non-active cracks within concrete elements caused by

shrinkage or other structural movement. Non-active cracks shall be injected with a low-

viscosity epoxy resin to fill and seal the crack and restore the structural integrity.

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2 Before to starting the injection operation it shall be established by testing and investigation

work that cracks manifest within concrete elements due to either or both shrinkage or

structural movement are non-active.

3 The extent of the cracks to be filled will be as directed by the Engineer. The cracks to be

filled shall be marked out in detail on the concrete elements by the Contractor and agreed

with the Engineer before proceeding.

4 The extent of the work may be adjusted by the Engineer as the project proceeds, according

to the conditions found.

5 Grease, oil or other contaminants shall be removed. Algae and other biological growth shall

also be removed by scrubbing with bactericide or detergent and clean water. If necessary,

wire brushes shall be used.

6 Loose or spalling areas of concrete, laitance, traces of paint or other coating materials within

the marked out scope of the work shall be removed.

7 All cracks shall be thoroughly cleaned out using clean, oil-free compressed air. Both the

concrete surface and the cracks shall be allowed to dry thoroughly before continuing.

8 The injection nipples shall be fixed at intervals along the length of each crack. The distance

between each nipple will depend on the width and depth of the crack.

9 Spacing shall be close enough to ensure that the resin will penetrate along the crack to the

next point of injection. This will normally be between 200 mm and 100 mm.

10 Each nipple shall be firmly bonded to the concrete surface by using a sealant. The sealant

shall be supplied in two pans (liquid base and hardener system). The two components shall

be thoroughly mixed together for 3 to 4 min until a putty-like consistency is achieved.

11 The mixed sealant shall be applied to the metal base of each surface-fixed nipple. They shall

be pressed firmly into place and held for several seconds until secure. The mixed sealant

shall be applied around each embedded nipple, ensuring a complete seal is made. In this

way, all the nipples shall be fixed along the length of the crack.

12 In the case of a wall or slab which is cracked all the way through, nipples shall be located on

both sides with those at the back placed at midway points between those it the front.

13 The surface of the cracks between the nipples shall be sealed with a band of sealant 30 to

40 mm wide and 2 to 3 mm thick. Both sides if cracks which go all the way through a wall or

slab shall be sealed in this way.

14 The prepared cracks shall be allowed to cure for 12 to 24 h. At low ambient temperatures

(5 °C to 12 °C) the curing time will be extended and the Contractor shall ensure that the

surface sealant has adequately cured before continuing.

15 One end of the injection hose shall be attached to the lowest nipple on vertical cracks or to

either end of horizontal cracks.

16 Each crack shall be treated in a single, continuous operation. Sufficient material shall

therefore be made ready before the commencement of the work.

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17 The Contractor shall to ensure that sufficient cracks are prepared to provide effective use of

the mixed material.

18 The preparation, mixing and application of the materials shall be undertaken in strict

accordance with the manufacturer's recommendations. The Contractor is to ensure that all

necessary tools and equipment are on Site.

19 Both the compressive strength and flexural strength shall be tested at 7 d.

20 The material shall exhibit excellent bond to concrete and when tested for tensile adhesion the

failure shall be in the concrete and not at the interface.

21 The injection resin shall be of a prepackaged or preweighed type and only the use of full units

will be allowed. No part packs or on-Site batching will be allowed under any circumstances.

22 In all operations of storage, mixing and application, the Contractor shall comply with the

health and safety recommendations of the manufacturer and governing authorities.

23 The injected system shall be allowed to cure for 24 h and shall be left undisturbed for this

time.

24 The nipples and bands of surface sealant shall then be removed and damaged areas made

good to the satisfaction of the Engineer.

25 The injection material shall be compatible with the host concrete and shall have the

properties shown in Table 16.4 when tested in accordance with the relevant standards.

Table 16.4

Property Requirement for Epoxy Crack Injection Material

Property Method Minimum Value

Compressive strength BS 4551, BS 2782 BS 6319 70 MPa

Flexural strength BS EN 12390-5

16.7 POLYESTER RESIN CONCRETE (PRC) - PIPING SYSTEMS FOR NON-

PRESSURE DRAINAGE AND SEWERAGE

16.7.1 General

1 Polyester resin concrete is a mixture formed from aggregates and fillers which are bound

together using a polyester resin (also called Polymer concrete pipes), as defined in ISO

18672-1 or ASTM D 6783 with the amendments given below.

2 Polyester resin concrete is permitted for use in infrastructure drainage and sewage systems

(pipes, manhalls, soakways).

16.7.2 Resin

1 The resin used in the pipe system and manufactured as per ISO 18672-1shall have a

temperature of deflection of at least 85 °C, when tested in accordance with Method A of

ISO 75-2 with the test specimen in the edgewise position. It shall also conform to the

applicable requirements of EN 13121-1.

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2 The resin used in the pipe system and manufactured as per ASTM D 6783 shall have a

minimum deflection temperature of 85°C when tested at 1.82 MPa following Test Method

D648. The resin content shall not be less than 7 % of the weight of the sample as determined

by Test Method D2584.

16.7.3 Minimum strength

1 The minimum strength classes for different pipe shapes are given below.

Table 16.4

Minimum strength classes for pipes designated PRC-OC or PRC-TC

Nominal size DN

Strength class Sc

N/mm

PRC-OC PRC-TC

150 ≤ DN ≤ 500 180 180

600 ≤ DN ≤ 1000 145 160

1200 ≤ DN≤ 3000 120 145

Table 16.5

Minimum strength classes for pipes designated PRC-OE or PRC-TE

Nominal width/height

WN/HN

Strength class Sc

N/mm

PRC-OE PRC-TE

300/450 ≤ WN/HN ≤ 600/900 180 180

700/1050 ≤ WN/HN ≤ 1000/1500 145 160

1200/1800 ≤ WN/HN ≤ 1400/2100 120 145

Table 16.6

— Minimum strength classes for pipes designated PRC-OK or PRC-TK

Nominal size

DN

Strength class Sc

N/mm

PRC-OK PRC-TK

800 ≤ DN ≤ 1000 145 160

1200 ≤ DN ≤ 1800 120 145

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 17: Structural Precast Concrete

17 STRUCTURAL PRECAST CONCRETE .................................................................. 2

17.1 GENERAL ............................................................................................................... 2

17.1.1 Scope 2

17.1.2 References 2

17.1.3 Submittals 3

17.1.4 Qualifications 4


17.1.6 Quality Control 5

17.1.7 Testing 6

17.1.8 Delivery, Storage and Handling 7

17.1.9 Design Loadings, Actions and Structural Members Selection 7

17.2 MATERIALS ............................................................................................................ 8

17.2.1 General 8

17.2.2 Reinforcing Bars 8

17.2.3 Bearing Pads 8

17.2.4 Embedded Steel 8

17.3 FORMING ............................................................................................................... 8

17.3.1 General 8

17.3.2 Tolerances 9

17.4 INSTALLATION ....................................................................................................... 9

17.4.1 General 9

17.4.2 Survey 9

17.4.3 Guying, Bracing and Shoring 9

17.4.4 Adjustment and Correction 9

17.4.5 Erection Tolerances 10

17.4.6 Welding 10

17.4.7 Grouting 10

17.4.8 Field Cutting 10

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17 STRUCTURAL PRECAST CONCRETE

17.1 GENERAL

17.1.1 Scope

1 The work included in this Section comprises furnishing all plant, labour, equipment,

appliances and materials and performing all operations in connection with Structural Precast

Concrete Work.


This Section


Part 3 ............... Cementitious materials

Part 5 ............... Admixtures

Part 6 ............... Property requirements

Part 7 ............... Concrete Plants

Part 8 ............... Transportation and placing of concrete

Part 9 ............... Formwork

Part 10 ............. Curing

Part 11 ............. Reinforcement

Part 15 ............. Hot weather concreting

17.1.2 References

1 The following standards and other documents are referred to in this Part:

AASHTO .................... Standard Specification for Highway Bridges, Section 25

ACI 523.2R ................. Guide for Precast Cellular Concrete Floor, Roof, and Wall Units

ACI 533R .................... Guide for Precast Concrete Wall Panels

ACI 533.1R ................. Design Responsibility for Architectural Precast-Concrete Projects

ACI 543R .................... Design, Manufacture, and Installation of Concrete Piles

ACI 550.1R-09 ............ Guide to Emulating Cast-in-Place Detailing for Seismic Design of

Precast Concrete Structures

ASCE/SEI 7-05 ........... Minimum Design Loads for Buildings and other Structures

ACI 318-11 ................. Building Code Requirements for Structural Concrete

BS 8110 ...................... The structural use of concrete.

BS EN 1991-1-4 ......... Eurocode 1. Actions on structures. General actions. Wind actions

BS EN 1992-1-1 ......... Eurocode 2. Design of concrete structures. General rules and rules for

buildings

ISO 9000, .................. Quality management systems. Fundamentals and vocabulary

Prestressed Concrete Institute (PCI) , Manual 116

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17.1.3 Submittals

1 Manufacturer's Literature:

(a) the Contractor shall provide copies of manufacturer's specifications and installation instructions for each item of proprietary material to be used, showing compliance with this specification. Information on equipment, embedded items and other accessories shall also be provided.

2 Design Mixes:

(a) copies of mix designs with support material

(b) the requirements of the mix design shall be in accordance with Parts 6 and 7 of this Section.

3 Product Design Criteria:

(a) loadings for design:

(i) initial handling and erection stresses

(ii) all dead and live loads as specified on the contract drawings or as required

(iii) all other loads specified for the member where they are applicable.

4 Product Design Calculations:

(a) the design calculations shall be performed by a Structural Engineer experienced in precast concrete design. They shall cover all stages of handling, transportation and erection. The design shall be carried out in accordance with the requirements of BS EN 1992-1-1 or relevant ACI codes, and shall be accepted by the Engineer.

(b) calculations for the design of precast members shall be supported by a statement explaining the principle of design and type of analysis adopted

(c) the influence of individual members in achieving the overall stability of the structure should be considered

(d) computer programmes used in the designs shall be fully described and details of input and printout shall be presented in a manner which can be readily understood and the following requirements shall be met:

(i) programme manuals and instructions to programme users shall be made available to the Engineer upon request

(ii) where such programme cannot be demonstrated by the Contractor to have been fully checked or where the Engineer considers it necessary, the Contractor shall run such test examples as the Engineer may choose, in order to verify the completeness and accuracy of the programme

(e) members that are exposed to the weather shall be designed to provide for the movement of components without damage, failure of joint seals, undue stress on fasteners or other detrimental effects when subject to seasonal or cyclic day/night temperature ranges

(f) precast systems shall be designed to accommodate construction tolerances, deflection of other building structural members and the clearance of intended openings

(g) calculate structural properties of framing members in accordance with BS 8110 or BS EN 1992-1-1, or relevant ACI codes.

5 Shop Drawings. The Contractor shall provide the following information for the approval of the Engineer:

(a) layout plans and detailed fabrication and placement drawings for each structural precast element

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(b) shop drawings are to include the following information:

(i) size, grade, profile and dimensions of all materials used

(ii) connection and anchorage details

(iii) lifting devices, locations and handling limitations

(iv) steel reinforcement details

(v) all openings, sleeves, inserts and other provisions in full co-ordination with all trades in the Contract

(vi) identification marks.

6 Erection Procedures:

(a) detailed outline of sequence and methods of erection including but not limited to types, capacities and numbers of cranage, methods of support and transportation.

7 Fabrication Records:

(a) A record shall be kept for every piece of precast element produced showing the following:

(i) type and number

(ii) date of pour

(iii) concrete test results

(iv) shop drawing reference number

(v) type and duration of curing

(vi) date of delivery to Site

(vii) date of fixing in position.

8 Test Reports:

(a) copies of all testing and inspection reports.

9 Trial Panels:

(a) the Contractor shall produce trial panels in accordance with the requirements of Part 10 of this Section.

(b) trial panels shall be retained for reference purposes for the acceptance of the production work.

17.1.4 Qualifications

1 Structural precast work shall be executed by an approved specialist Subcontractor for casting and also for transportation, handling and erection.

2 The Contractor may execute this work himself if he can satisfy the Engineer that he has sufficient experience and expertise in this field. As a minimum the Contractor shall:

(a) provide satisfactory evidence that his tradesmen and their supervisory personnel engaged in such work have successful experience with work comparable to that shown and specified

(b) provide details of organised quality control and testing procedures.


1 The precast concrete supplier shall have a quality assurance scheme that meets ISO 9000 or equivalent.

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2 All work shall be performed to secure for the project homogeneous concrete having the required strength, surface finish, materials, durability, and weathering resistance, without planes of weakness or other structural defects, and free of honeycombs, air pockets, voids, projections, offset of plane and other defacements of concrete.

3 No alterations or substitutions of the structural systems shown on the Drawings are permitted unless otherwise specified.

4 The Contractor shall supervise and co-ordinate all phases of the structural precast concrete construction process and be responsible for the complete manufacturing process.

5 All methods of manufacture and practices of handling raw materials and manufactured concrete shall be reviewed by the Engineer before execution of the structural precast concrete work, at least 14 days before the beginning of precasting work.

6 Only materials of known quality shall be incorporated in the work.

7 All materials shall be properly selected, reviewed and approved by the Engineer before use, and maintained during shipment, storage and use.

8 Construction systems and techniques shall be properly selected, reviewed and approved by the Engineer before use, and maintained throughout the complete structural precast concrete construction phase.

9 Adequate spare equipment, parts, additional components and repair facilities shall be available for all tools and equipment.

10 Regardless of approvals by the Engineer, the Contractor shall be responsible for all materials and methods of structural precast concrete work.

11 If work does not meet the specified requirements, the Contractor shall at no additional cost to the Employer:

(a) implement removal, replacement or remedial work

(b) revise procedures or materials to prevent recurrence of unacceptable work.

17.1.6 Quality Control

1 The Contractor shall prepare and provide his quality control programme for structural precast

concrete work with particular attention to details, pre-checking processes, procedures and

close supervision, and in particular the Contractor shall:

(a) in order to assure that proper work is performed to prevent later corrective actions,

assign at least one experienced supervisor full time to provide quality control for

structural precast concrete work

(b) the assignment will not relieve the Contractor's other quality control personnel of their

duties relative to the quality control of the structural requirements and surface finish of

the structural precast concrete work.

2 The Contractor shall arrange for the training of his quality control personnel who will perform

quality control of structural precast concrete work and whose training shall include but not be

limited to:

(a) materials evaluation

(b) special mix design techniques

(c) mix placement

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(d) vibrator selection and use

(e) formwork details formwork protection

(f) release agent use

(g) reinforcing steel

(h) detailing and installation

(i) finishing equipment and techniques

(j) corrective procedures and protection of completed work.

3 The Contractor's quality control personnel shall be responsible for verifying all details

necessary to produce the final structural design objectives.

4 The Contractor's quality control personnel shall also verify the quality of the structural precast

concrete work and guide the production of results which will be within acceptable physical

tolerances

17.1.7 Testing

1 Concrete shall be tested as specified in Part 6 of this Section.

2 The Contractor shall:

(a) furnish labour required to facilitate testing

(b) inform the Engineer with at least one day's advance notice when concrete is to be

placed

(c) provide storage facilities for concrete test cubes

(d) provide material samples and access to materials as required for testing.

3 Should the batching plant be located more than 500 meters away from the site offices, the

Contractor shall provide suitable transport acceptable to the Engineer, for the sole use of the

Engineer's staff.

4 The Contractor shall station a qualified technician at the casting site to continuously test,

inspect and report on the following:

(a) that concrete testing is being carried out in accordance with the requirements of Part 6

of this Section

(b) check the following and verify conformance with specified requirements and approved

shop drawings:

(i) all reinforcing bars

(ii) all embedded items

(iii) all formwork

(c) check all openings and provisions for co-ordination with all trades in the Contract as

shown on approved shop drawings.

5 The Contractor shall provide facilities and equipment for the conducting of all tests specified

herein except for the strength test which should be carried out by an approved independent

testing agency.

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17.1.8 Delivery, Storage and Handling

1 The structural precast elements shall be removed from the form without damaging or over

stressing and stored or placed for transportation on a stable bed that will not allow distortion

of the member.

2 Separate stacked members with suitable battens and bracing.

3 Mark each member with an identifying reference or piece mark, and the date of casting.

4 All piece marks are to be correlated with test reports and plan layouts or erection drawings.

5 The structural precast element shall be transported with sufficient battens, bracing, and

supports so as to prevent over-stress by vibration or impact loadings. The Contractor shall

submit his proposed method of transportation to the Engineer for approval.

6 Structural precast units shall be stored, handled and transported in a manner that will avoid

undue strains, hair cracks, staining, or other damage.

7 The Contractor shall deliver the units from the casting site to the project Site in accordance

with schedule and proper setting sequence.

8 Structural precast units shall be stored free of the ground and protected from wind or rain

splashes.

9 The units shall be covered and protected from dust, dirt or other staining materials.

10 During fabrication, construction and after erection, the Contractor shall protect the castings to

avoid the possibility of damage.

17.1.9 Design Loadings, Actions and Structural Members Selection

1 The provisions of this Clause shall apply if the Contractor is responsible for the design of the

structural precast units.

2 The precast elements shall be designed to withstand all loading conditions against which

strength and serviceability must be measured.

3 Vertical loads shall include the self-weight of precast elements, floor coverings and live loads

as indicated on the contract drawings.

4 The wind loads shall be calculated based on the wind speed provided in Section 1 part 1

clause 1.5.2.

5 Account shall be taken of the loads and deformation caused by temperature and time

dependent deformations. For such purpose 55 °C temperature variation and 90 % relative

humidity should be considered for all members, except exterior elements and facade

elements shall consider 85 oC.

6 Precast elements shall be designed in accordance with BS EN 1992-1-1 or relevant ACI

code. Design tensile stresses should not exceed the design flexure tensile stress of concrete,

at the particular age of the concrete.

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7 Nominal cover to steel including links must meet the durability requirement of severe

condition of exposure and to meet requirement for 2 h period of fire resistance, as provided

for in BS EN 1992-1-1 or relevant ACI code.

8 Total deflection of precast elements should be limited to 1/350 of the span of this element.

9 Plan and design for openings for building services, where required or necessary.

17.2 MATERIALS

17.2.1 General

1 The Contractor shall obtain cement, aggregates and water from a single source, sufficient to

complete the entire structural precast concrete work to assure regularity of appearance and

uniformity of colour.

2 The Contractor shall provide all materials in accordance with and meet all applicable

requirements of this section.

17.2.2 Reinforcing Bars

1 Reinforcing bars shall conform to the requirements of Part 11 of this Section

17.2.3 Bearing Pads

1 These shall be Elastomeric neoprene, conforming to AASHTO Standard Specifications for

Highway Bridges (Section 25) with the following stipulations:

(a) use unfactored loads for design

(b) maximum compressive stress, 0.70 MPa

(c) maximum shear stress, 0.07 MPa

(d) maximum shear deformation, 1/2 thickness

(e) maximum compressive strain, 15 %

17.2.4 Embedded Steel

1 All embedded items shall be of stainless steel Grade 316L.

17.3 FORMING

17.3.1 General

1 Forms and casting beds are to be firmly seated so as not to deflect or be displaced under

concreting or tensioning loads.

2 Correct for thermally induced strains or forces.

3 For member penetrations larger than 150 mm, coring or field cutting is not permitted unless


4 Clean and coat forms with release agent before installation or reinforcing or embedments.

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17.3.2 Tolerances

1 Permissible deviations of formed surfaces are not to exceed tolerances outlined in PCI

Manual 116, with items as summarised or modified in Table 17.1

Table 17.1

Tolerances for Structural Precast Concrete

Description Tolerance

Dimensions

Length: 5 mm

Width: 3 mm

Thickness: Stem 3 mm; Flange 2.0 mm.

Embedment or penetration location: 0.2 %

Straightness: 3 mm. for 300 cm

End squareness: 3 mm

17.4 INSTALLATION

17.4.1 General

1 The Contractor’s erection responsibilities include the safe and proper placing, aligning, and

levelling of the structural precast elements on the accepted bearing surfaces and affecting

their proper fastening.

17.4.2 Survey

1 Before placement of the structural precast elements the Contractor shall survey and maintain

all temporary supports shown or required to control alignment, and deflection.

2 Temporary supports shall be retained until framing elements braced thereby have attained

integral stability in accordance with the design.

17.4.3 Guying, Bracing and Shoring

1 The Contractor shall install in proper sequence and maintain all temporary supports shown or

required to control alignment, deflection and stress levels.

2 Temporary supports shall be retained until framing elements braced thereby have attained

integral stability in accordance with the design.

17.4.4 Adjustment and Correction

1 The Contractor shall compensate and correct for the misaligning affect of temperature, draw

from welding, bolting or erection sequence or grouting.

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17.4.5 Erection Tolerances

1 The following erection tolerances shall apply unless otherwise specified in the Contract:

(a) Variations from plumb 6 mm in 6 m run;

12 mm total in a12 m or longer run

(b) Variation from level or elevation 6 mm in runs;

12 mm in 12 m run; maximum 12 mm at

single locations

(c) Variation from position in plan 12 mm maximum.

(d) Offsets in alignment of adjacent

members at joints 1.5 mm in 3 m run, 6 mm maximum.

17.4.6 Welding

1 Where permission for welding is given by the Engineer, the following shall apply:

(a) welding shall not take place until all adjacent elements to be connected have been

aligned, firmly seated and braced

(b) control of heat build-up by limiting voltage, electrode size, and rate

(c) spalled or heat damaged concrete around weldments shall not be acceptable.

17.4.7 Grouting

1 Joints, gaps and connections shall be filled with grout as shown on the Drawings and as


17.4.8 Field Cutting

1 Field cutting of holes may be done only with the Engineer's concurrence, and only with power

saws or core drills. Steel reinforcement or prestressing strand shall be avoided, where the

reinforcement or strand is damaged the unit shall be repaired to the satisfaction of the

Engineer, or rejected.

2 The maximum hole size shall be 150 mm diameter or as limited by member size or strand

location

3 Any cracks, spalls and sharp corners created by field cutting are to be ground, eased, and

patched with epoxy type bonding and patching compounds.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 18: Prestressed Concrete

18 PRESTRESSED CONCRETE ................................................................................. 2

18.1 GENERAL ............................................................................................................... 2

18.1.1 Scope 2

18.1.2 References 2

18.1.3 Submittals 3

18.1.4 Storage and Handling 3

18.2 PRESTRESSING .................................................................................................... 3

18.2.1 General 3

18.2.2 Wires and Strands 4

18.2.3 Sheaths, Cores and Ducts 5

18.2.4 Anchorages 5

18.2.5 Jacking Equipment 5

18.2.6 Tensioning 6

18.2.7 Grouting 7

18.2.8 Grout Mixer 7

18.2.9 Grout Trials 8

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18 PRESTRESSED CONCRETE

18.1 GENERAL

18.1.1 Scope

1 This section describes the requirements for prestressed post-tensioned concrete, including

materials and procedures for installation, stressing and grouting.


This Section


Part 3 ............... Cementitious Material

Part 4, ........... Water

Part 5, ........... Admixtures

Part 6, ............ Property requirements

Part 7, ........... Concrete Plants

Part 8, ............ Transportation and placing of concrete

Part 9, ........... Formwork

Part 10, ........... Curing

Part 11, ........... Reinforcement

Part 15, ........... Hot weather concreting

Part 16, ........... Miscellaneous

18.1.2 References

ACI 325.7R ------------- Recommendations for Designing Prestressed Concrete Pavements ACI 343R ---------------- Analysis and Design of Reinforced Concrete Bridge Structures ACI 350.3R ------------- Seismic Design of Liquid-Containing Concrete Structures ACI 358.1R ------------- Analysis and Design of Reinforced and Prestressed-Concrete

Guideway Structures ACI 372R ---------------- Design and Construction of Circular Wire- and Strand-Wrapped

Prestressed-Concrete Structures ACI 373R ---------------- Design and Construction of Circular Prestressed Concrete Structures

with Circumferential Tendons ACI 423.3R ------------- Recommendations for Concrete Members Prestressed with Unbonded

Tendons ASTM A881/A881M -- Standard Specification for Steel Wire, Deformed, Stress-Relieved or

Low-Relaxation for Prestressed Concrete Railroad Ties ASTM A882/A882M- -- Standard Specification for Filled Epoxy-Coated Seven-Wire

Prestressing Steel Strand ASTM A641/A641M – Standard Specification for Zinc-Coated (Galvanized) Carbon Steel

Wire

ASTM A416/A416M-10 Standard Specification for Steel Strand, Uncoated Seven-Wire for

Prestressed Concrete

AWWA D110-------------Wire- and Strand-Wound, Circular, Prestressed Concrete Water

Tanks

BS 1881 ...................... Testing Concrete.

BS EN 12350, ............. Testing fresh concrete

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BS EN 12390, ............. Testing hardened concrete

BS 5896, ..................... Specification for high tensile steel wire and strand for the prestressing

of concrete.

BS EN 1992 Eurocode 2: Design of concrete structures

GSO ISO 1920, .......... Testing of concrete

18.1.3 Submittals

1 Samples

(a) a 1 m length sample of strand shall be taken from every 1000 m of strand to be installed in the works with a minimum of one sample of strand per reel, on Site in the presence of the Engineer for strength test at an independent laboratory approved by the Engineer. A reel shall only be accepted if both the breaking load and the 0.1 % proof load of the sample exceed the characteristic load given in BS 5896 Table 6

(b) a minimum of three samples of strand shall be taken at random from each reel of prestressing steel on Site in the presence of the Engineer. The reels on Site shall only be accepted if the relaxation values determined by the tests are equal to or lower than the specified relaxation class of BS 5896.

(c) Sample requirements and frequency for prestressing wire shall meet the requirements of AWWA D110 and ACI 372R.

2 Technical details of the proposed materials and equipment shall be submitted. Details of the jack type and size shall be submitted to allow for clearances to be checked. A calibrated stress-recording device shall be used. Design Data. The Contractor shall submit:

(a) details of the proposed grout mix design

(b) tendon extension calculations

(c) vent pipe spacing and location details.

(d) detailed execution and shop drawings

(e) calculation notes

3 Other Submittals. The Contractor shall also submit:

(a) Curriculum vitae and experience record of the supervisor proposed, who shall have a minimum of five years experience in such a position

(b) Safety procedures, including warning signs, barricades and communication between different stressing locations

(c) The name of the proposed the prestressing company, giving details of previous projects.

18.1.4 Storage and Handling

1 Prestressing steel shall be stored on palettes at least 300 mm above the ground, and be protected from contamination by wind blown sand or rain.

2 Prestressing strand shall be in coils of sufficiently large diameter to ensure that the strand pays off straight.

18.2 PRESTRESSING

18.2.1 General

1 Prestressing operation shall be carried out only under the direction of an experienced and competent supervisor and all personnel operating the stressing equipment shall have been properly trained in its use.

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2 In addition to the normal precautions against accident, which should be taken at all times for

the whole of the Works, special care shall be taken when working with or near tendons which

have been tensioned or are in the process of being tensioned.

3 The system of prestressing used shall be a system approved by the Engineer. Such system

shall be used strictly in accordance with the recommendations of the system manufacturer.

4 Under no circumstances shall equipment or fittings designed for use with one system of

prestressing be used in conjunction with equipment and fittings designed for use with another

system.

5 Prestressing components shall be stored in clean dry conditions. They shall be clean and

free form loose rust and lose mill scale at the time of fixing in position and subsequent

concreting. Slight rusting of the steel, which can be removed by moderate rubbing, is

acceptable, but the surface shall not show signs of pitting.

18.2.2 Wires and Strands

1 All prestressing strands shall be seven-wire super stabilised low relaxation strands with a

Guaranteed Ultimate Tensile Strength (GUTS) of not less than 1770 MPa, complying with BS

5896 or relevant ASTM standards.

2 All prestressing wire shall be cold-drawn, high-carbon wire meeting the requirements of

ASTM A821/A821M, Type B having a minimum ultimate tensile strength of 1,448 MPa

(210,000 psi) prior to galvanizing. Zinc coating for galvanizing shall meet the requirements of

ASTM A641/A641M, with a minimum weight per unit area of uncoated wire surface of 259

g/m2 (0.85 oz/ft2). The minimum ultimate strength of the wire after galvanizing shall be no

less than 1,241 MPa (180,000 psi).

3 All wires or strands to be stressed at the same time shall be taken from the same parcel. The

coil numbers of the steel used for each tendon shall be recorded.

4 Welding of tendons shall not be permitted.

5 All cutting of strands shall be carried out using a high-speed abrasive cutting wheel or friction

saw at not less than one diameter from the anchor. Cutting shall take place only after the

Contractor has submitted the stressing records and the Engineer has approved them in

writing. Flame cutting will not be permitted.

6 Tendons shall be built into the Works strictly in accordance with the system which is being

employed.

7 Sufficient strand shall project from the anchorage to allow jacking to take place at the

stressing end of the tendon.

8 The cable (tendons) or individual strands comprising the cable shall not be kinked or bent.

No strand that has become unravelled shall be used.

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18.2.3 Sheaths, Cores and Ducts

1 Sheaths shall be accurately located both vertically and horizontally as described in the

Specific Project Specification. Unless otherwise described in the Specific Project

Specification the tolerance in the location of the centre line of the sheath shall be within

5 mm.

2 All sheaths and cores shall be maintained in their correct positions during the placing of the

concrete. Unless otherwise agreed with the Engineer, sheaths shall be rigidly supported at

points not less than 50 mm and not more than 500 mm apart. The method of support shall be

to the approval of the Engineer.

3 Where sheaths are used, the number of joints shall be kept to a minimum and sleeve

connectors shall be used for jointing. Each joint shall be adequately sealed against the

ingress of material. Joints in adjacent sheaths shall be staggered by at least 300 mm

4 Sheaths shall be kept free of matter detrimental to the bond between the grout and the

sheath and, except for material sealing a sheath joint, between the sheath and concrete.

5 Within 24 hours of the concrete being placed the Contractor shall satisfy the Engineer that

the tendons are free to move if they are in ducts or that the ducts are free from obstruction.

6 The number and position of grout vents for entry and outlet points and for checking that the

entire length of duct has been adequately grouted, shall be agreed with the Engineer before

the ducts are formed.

7 Vents shall be provided at low points in the tendon profile to allow the disposal of water that

may have collected as a result of rain or curing, for example. The vents shall be sealed

before grouting operations beginning.

18.2.4 Anchorages

1 Anchorages, end blocks and plates shall be positioned and maintained in position during concreting so that the centre line of the duct passes axially through the anchorage assembly.

2 All bearing surfaces shall be clean before concreting and tensioning.

3 Anchoring of prestressing wires shall meet the requirements of AWWA D110 and ACI 372R.

18.2.5 Jacking Equipment

1 All jacking equipment used for stressing operations shall be of the type applicable to the system adopted.

2 Jack and pumps shall be calibrated at an independent facility, in the presence of the Engineer, before beginning stressing operations. Calibration of the equipment shall take place at six-month intervals for equipment permanently present on Site. Whenever new equipment is brought to the Site, or equipment is removed and returned, or serviced, recalibration of the equipment as described will be required.

3 All gauges, load cells, dynamometers and other devices used for measurement shall have a

reading accuracy of within 2 %.

4 Stressing equipment for prestressing wires shall meet the requirements of AWWA D110 and ACI 372R.

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18.2.6 Tensioning

1 The Contractor shall submit details of the proposed stressing loads and stressing sequence

to the Engineer for approval.

2 Tensioning shall be carried out only in the presence of the Engineer or his representative

unless permission has been granted to the contrary.

3 The Contractor shall ensure that personnel carrying out the stressing are provided with

particulars of the required tendon loads, order of stressing and extensions.

4 Immediately before tensioning, the Contractor shall prove that all tendons are free to move

between jacking points.

5 Unless otherwise permitted in the Contract, concrete shall not be stressed until it has

reached at least the age at which two test cubes taken from it attain the specified transfer

strength. The cubes shall be made and tested as described in BS 1881 , BS EN 12350, BS

EN 12390 or GSO ISO 1920. They shall be cured in similar conditions to the concrete to

which they relate to, and in a manner approved by the Engineer.

6 The friction factors assumed for the calculation of tendon extension shall be verified by on

Site measurement of the force-extension relationship of a typical sample of installed tendons.

7 The Contractor shall establish the datum point for measuring extension and jack pressure to

the satisfaction of the Engineer.

8 The tendons shall be stressed at a gradual and steady rate until they attain the force

required.

9 The maximum force exerted on the shall not exceed 75 % of the GUTS of the strand. For the

purposes of cable detensioning, where the installed strand is to be discarded the jacking

force may be increased to 80 % GUTS.

10 The force in the tendons shall be obtained from the readings on a load cell or pressure gauge

and the extension of the tendons measured. The two readings shall conform to the limits set

by the Engineer but in all cases the force in the tendon as computed from the extension

measurement shall be within +5 % to -2 % of the force indicated by the gauging system.

11 When stressing from one end only the pull in at the dead end shall be accurately measured

and the appropriate allowance made in the measured extension at the live end.

12 If the calculated and measured extensions vary from each other by more than 6 % then

corrective action shall be taken. This may involve detensioning and retensioning of the

tendons if required by the Engineer.

13 When the required force, including overloads of short duration, has been applied to the

satisfaction of the Engineer, the tendons shall be anchored. The jack pressure shall then be

relieved in such a way as to avoid shock to the anchorage or tendons.

14 If the pull-in of tendons at the completion of anchoring is greater than that acceptable to the

Engineer, the tendons shall be detensioned and the tendon tensioned again.

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15 The Engineer may direct that the force in any tendon be tested by rejacking. This will only be

instructed if there is doubt that the calibration of tensioning equipment is accurate. Care shall

be exercised by the Contractor during the retensioning to ensure that the jacking load does

not exceed more than 80 % of the GUTS of the strand.

16 If it is necessary to crop the tendons to enable the ducts to be grouted, this shall be delayed

as long as is practicable up to the time of grouting. In all other cases, unless otherwise

agreed with the Engineer, the tendons shall not be cropped less than three days after

grouting.

17 The Contractor shall keep full records of all tensioning operations, including the measured

extensions, pressure gauge or load cell readings and the amount of pull-in at each

anchorage. Copies of these records, on suitable forms, shall be supplied to the Engineer

within 24 hours of each tensioning operation.

18 Tensioning prestressing wires shall meet the requirements of AWWA D110 and ACI 372R

18.2.7 Grouting

1 Grouting shall take place only with the written approval of the Engineer.

2 All ducts shall be thoroughly cleaned by means of compressed air and all anchorages shall

be sealed before grouting.

3 Ducts shall be grouted as soon as practicable after the tendons in them have been stressed

and the Engineer’s written permission to commence has been obtained. Grout shall be

injected in one continuous operation and allowed to flow from the vents until the consistency

is equivalent to that being injected. The maximum time between mixing and injection shall not

exceed 30 min.

4 The ducts shall be completely filled with grout.

5 Vents shall be sealed consecutively in the direction of flow and the injection tube sealed

under pressure until the grout has set. The filled ducts shall be protected to the satisfaction of

the Engineer to ensure that they are not subject to shock or vibration for one day.

6 Two days after grouting, the level of grout in the injection and vent tubes shall be inspected

and made good if necessary.

7 The Contractor shall keep full records of grouting including the date each duct was grouted,

the proportions of the grout and admixtures used, the pressure, details of interruptions and

topping up required. Copies of these records shall be supplied to the Engineer within three

days of grouting.

8 Prestressing wires shall be protected against corrosion and other damage by a shotcrete

cover coat meeting the requirements of AWWA D110 and ACI 372R

18.2.8 Grout Mixer

1 The grout mixer shall produce a grout of colloidal consistency. The grout injector shall be

capable of continuous operation with a sensibly constant pressure up to 0.7 MPa and shall

include a system of circulating or agitating the grout whilst the actual grouting is not in

progress. All baffles to the pump shall be fitted with sieve strainers size BS 14.

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2 The equipment shall be capable of maintaining pressure on completely grouted ducts and

shall be fitted with a nozzle which can be locked off without loss of pressure in the duct.

3 The pressure gauges shall be calibrated before they are first used in the Works and

thereafter as required by the Engineer. All equipment shall be thoroughly washed with clean

water at least once every three hours during grouting operations and at the end of use for

each day.

4 The Contractor shall ensure that standby grouting equipment is available in the event of a

breakdown.

18.2.9 Grout Trials

1 The Contractor shall carry out grouting trails to the satisfaction of the Engineer before actual

grouting taking place.

2 Unless otherwise directed or agreed as a result of grouting trials, the grout shall:

(a) consist only of ordinary Portland cement, water and an approved expansion agent

(b) have a water: cement ratio as low as possible consistent with the necessary

workability. Under no circumstances shall the water: cement ratio exceed 0.4

(c) not be subject to bleeding in excess of 2 % after 3 h or 4 % maximum when measured

at 18 oC in a covered glass cylinder approximately 100 mm diameter with a height of

approximately 100 mm and the water shall be reabsorbed after 24 h.

3 Admixtures containing chloride or nitrates shall not be used. Other admixtures shall be used

only with the written permission of the Engineer and shall be used strictly in accordance with

the manufacturer’s instructions.

4 The grout shall be mixed for a minimum of 2 minutes and until a uniform consistency is

obtained.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 19: Testing of Water Retaining Structures

19 TESTING OF WATER RETAINING STRUCTURES................................................ 2

19.1 GENERAL ............................................................................................................... 2

19.1.1 Scope 2

19.1.2 References 2

19.1.3 Submittals 2

19.1.4 General 2

19.2 TESTING ................................................................................................................. 2

19.2.1 General 2

19.2.2 Cleaning 3

19.3 TESTING PROCEDURE ......................................................................................... 4

19.3.1 Walls 4

19.3.2 Roofs 5

19.3.3 Disposal of Water Used for Testing 5

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19 TESTING OF WATER RETAINING STRUCTURES

19.1 GENERAL

19.1.1 Scope

1 This Part of the specification applies to the testing of structures that are designed with the

intention of retaining water.


This Section

Part 1 ............... General

Part 13 ............. Inspection and Testing of Hardened Concrete

Part 14 ............. Protective Treatments for Concrete

19.1.2 References

BS 8007 ...................... Code of Practice for Design of concrete structures for the retaining of

aqueous liquids

19.1.3 Submittals

1 The Contractor shall record and submit to the Engineer within 24 hours the results of the

watertightness tests carried out.

19.1.4 General

1 Water retaining structures shall be watertight when subjected to external groundwater

pressures or to tests as specified in this Part.

19.2 TESTING

19.2.1 General

1 The Contractor shall test watertightness of water retaining structures including storage

reservoirs and other miscellaneous structures that require to be watertight.

2 All water used for testing shall be potable or irrigation water and the Contractor shall make

arrangements for the supply and disposal of this water.

3 Water retaining structures shall be tested for watertightness after completion, in accordance

with the following method or as directed by the Engineer:

(a) the structure shall be filled with potable or irrigation water in stages not exceeding 1 m

in 24 h held at each water level for such time as the Engineer may require. Should

dampness or leakage occur, the water shall be drawn off and the defects remedied to

the satisfaction of the Engineer

(b) in the case of structures which are subdivided into individual tanks, each individual

tank shall be tested separately. In the case of underground or partially underground

structures, the testing shall take place before application of water proofing membrane,

liner material or perimeter drain, filter material or backfilling is placed against the walls

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(c) in the case of hopper bottomed tanks, this shall be taken to mean that no material is

placed against the vertical external walls of the tank, the sloping walls of the hopper

bottoms of the tanks being assumed built directly against the excavation apart from the

blinding concrete

(d) no placing of material against the walls shall take place until the Engineer has given

his written approval and acceptance of the water retaining structures as watertight

(e) filling shall not take place earlier than 28 d after the casting of the final sections of the

structure which will be stressed by the filling of the structure.

(f) testing shall not be undertaken until the structure to be tested has been; completed

structurally including roof, if any, and has been passed by the Engineer in writing as

satisfactory in all respects other than watertightness, especially in regard to the final

finish of the work

(g) not withstanding the satisfactory completion of the seven day test, leakage, cracks,

and damp patches and sweating visible on the outside faces of the structure shall be

rectified from the water face by an injection system to the approval of the Engineer

(h) repair making the outer face only watertight wall not be accepted, this applies to bobbin

holes also

(i) the structure shall be retested until the watertightness is approved by the Engineer.

(j) should the structure fail a test in the above respects, the Contractor shall immediately

take such steps as may be necessary to:

(i) ascertain the nature and positions of defects or leakage's

(ii) empty the structure

(iii) remedy the defects in a manner approved by the Engineer, employing workers

who are specialists in this class of work

(k) when the remedial work has been completed in the manner approved by the Engineer,

the testing and if necessary rectification shall be repeated until a satisfactory test is

achieved.

(l) if necessary, in extreme cases of lack of watertightness, the Engineer may reject the

structure or portions thereof.

19.2.2 Cleaning

1 All water retaining structures shall, on completion, be carefully cleaned of all debris, to the

complete satisfaction of the Engineer as follows:

(a) shall be brushed down on all internal faces with a stiff broom while still dry

(b) all resulting debris removed

(c) all associated reservoir pipe work shall be cleaned in accordance with the specified

requirements

(d) the structure shall then be flooded with approximately 75 mm of clean water

(e) whole of internal faces shall be carefully brushed down with stiff brooms using the

water continuously until all faces are clean

(f) water shall then be drained off

(g) walls and floors hosed and flushed with clean water until perfectly clean.

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19.3 TESTING PROCEDURE

19.3.1 Walls

1 After completion and cleaning of the structure and all associated pipe work, if any, the

Contractor shall fill the structure up to the top water level and leave for a stabilising period of

21 d in order to allow for absorption and autogenous healing to take place.

2 Water shall be added over this period to maintain the top water level.

3 The Contractor shall ensure that all pipes and specials are available in ample time ahead of

testing.

4 Two sets of evaporation trays shall be provided along with two sets of rain gauges.

5 Levels in the trays and structure shall be made and recorded by a hook gauge with vernier

attachments.

6 Before and during testing, flows in the structure under drainage, if any, shall be monitored,

measured and recorded.

7 Each under drain shall be numbered and observations reported by under drain number to

facilitate analysis of the data.

8 All leaks shall be repaired within one month of their detection.

9 On the twenty-second day, two shallow watertight evaporation trays of area 0.4 m2 shall be

filled with 75 mm of water and placed to float in the structure.

10 The water level in the structure shall be recorded and the test commenced and carried out

over the next 7 d.

11 Readings of water levels in the structure and trays shall be made and recorded every 24 h

over this period.

12 If the water level in the tank falls by more than indicated by the evaporation trays, or other

sign of leakage occurs by the end of the test period then the Contractor shall search and

mark all areas of defect.

13 The structure shall then be emptied and the defects made good as specified herein.

14 After completion of remedial measures the structure shall be refilled and the test repeated.

15 This process shall be repeated until the structure is watertight to the satisfaction of the

Engineer.

16 The fall of water level in the structure over the test period of 7 d, minus the fall accounted for

by evaporation and rainfall shall not exceed 1/500 of the average water depth of the full

structure or 10 mm whichever is less.

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19.3.2 Roofs

1 The roofs of structures shall be tested for watertightness before laying of roof membrane.

2 Roof and fittings shall be hosed down vigorously and this shall be repeated in such a way as

to keep the roof wet for three successive days.

3 Roof and fittings shall be deemed satisfactory for watertightness if no discernible leaks or

damp patches show in the soffit.

4 Roof covering shall be completed as soon as possible after testing.

19.3.3 Disposal of Water Used for Testing

1 The Contractor shall provide suitable means for disposal of water used for testing, such that

no damage results to facilities, structures or property.

2 These means shall be subject to the approval of the Engineer and local authorities.

3 Details shall be submitted to Engineer on request.

4 The Contractor shall be responsible for damage caused by his filling, testing, flushing and

wastewater disposal operations.

END OF PART

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QCS 2014 Section 05: Concrete Page 1 Part 20: Personnel Qualifications and Certification

20 PERSONNEL QUALIFICATIONS AND CERTIFICATIONS ..................................... 2

20.1 GENERAL ............................................................................................................... 2

20.2 AUDITORS .............................................................................................................. 2

20.3 READY MIXED CONCRETE COMPANIES ............................................................. 2

20.3.1 Technical Department 2

20.3.2 Production and Operation Department 4

20.4 TESTING LABORATORIES .................................................................................... 5

20.4.1 Concrete Laboratory Department 5

20.5 CONTRACTORS ..................................................................................................... 6

20.5.1 Concrete Construction Department 6

20.6 CONSULTANTS ...................................................................................................... 7

20.6.1 Site Supervision Department 7

20.6.2 Site Supervision / Design Office Department 7

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20 PERSONNEL QUALIFICATIONS AND CERTIFICATIONS

20.1 GENERAL

1 The qualification requirements given in this part are optional unless otherwise mentioned

below. The purpose of the qualifications is to prepare the industry to cope with the required

quality of construction. The requirements will become compulsory as and when stated by

Qatar Standards.

2 Qualifications shall be approved by Qatar Standards or their representatives.

20.2 AUDITORS

1 Qatar Standards auditors and their approved representatives shall be qualified for inspecting

concrete ready mix plants and testing laboratories.

20.3 READY MIXED CONCRETE COMPANIES

20.3.1 Technical Department

1 Position: Technical Manager / QC Manager

Qualifications:

(a) Concrete specification review and concrete mixture proportioning

(b) Concrete constituent materials, their characteristics, and effects on concrete properties

(c) Fresh and hardened concrete properties

(d) Durability of concrete

(e) Production and delivery of Ready Mixed Concrete

(f) Handling, placing and curing of concrete

(g) Specifying and evaluation of concrete strength

(h) Testing of concrete and its constituents

(i) Quality control procedures and statistical analysis

(j) Hot weather concreting

(k) Troubleshooting concrete problems

2 Position: Site Supervisor

Qualifications:

(a) The supervisor shall be capable of satisfactorily reading, understanding and

performing the below fresh concrete tests:

BS EN 12350-1 .......... Testing fresh concrete - Sampling

ASTM C1064/C1064M Temperature of freshly mixed hydraulic-cement concrete

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BS EN 12350-2 .......... Testing fresh concrete – Slump test

BS EN 12350-6 ......... Testing fresh concrete – Density

BS EN 12390-2 ......... Testing hardened concrete – Making and curing specimens for

strength tests

ASTM C1611/C1611M Standard test method for slump flow of self consolidating concrete

3 Position: Lab Supervisor

Qualifications:


performing the below fresh and hardened concrete tests:

BS EN 12350-1 ......... Testing fresh concrete - Sampling


BS EN 12350-2 ......... Testing fresh concrete – Slump test


BS EN 12350-7 ......... Testing fresh concrete – Air content (Pressure Method)


strength tests


BS EN 12390-3 .......... Testing hardened concrete - Compressive strength of test specimens

BS EN 932-1 ............. Aggregates - Methods of sampling

BS EN 932-2 ............. Aggregates – Methods of reducing laboratory samples

BS EN 933-1 ............. Aggregates – Determination of particle size distribution (and dust

content)

BS EN 1097-6 ........... Aggregates – Determination of particle density and water absorption

BS EN 1097-3 ........... Aggregates – Determination of loose bulk density and voids

ASTM C566 – ............ Method of determination of moisture content

4 Position: Site Technician (compulsory if requested by the Engineer)

Qualifications:

(a) The technician shall be capable of satisfactorily performing the below fresh concrete

tests:






strength tests


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5 Position: Lab Technician (compulsory if requested by the Engineer)

Qualifications:

(a) The technician shall be capable of satisfactorily performing the below fresh and

hardened concrete tests:







strength tests


BS EN 12390-3 ......... Testing hardened concrete - Compressive strength of test specimens




content)




20.3.2 Production and Operation Department

1 Position: Plant/Production/Operation Manager and/or Supervisor

Qualifications:

(a) Properties of concrete and its constituents

(b) Materials management

(c) Plant design, function and maintenance

(d) Batching operations, procedures and dispatching

(e) Materials management and inventory

(f) Safety regulations and procedures

2 Position: Plant Operator

Qualifications:

(a) Basic concrete properties and characteristics of its constituents

(b) Scales, meters and batching sequence and control system

(c) Central mixing and discharging

(d) Tolerances, overweight/underweight controls

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(e) Troubleshooting scales, gates and other plant components

(f) Safety procedures

20.4 TESTING LABORATORIES

20.4.1 Concrete Laboratory Department

1 Position: Laboratory Manager / QC Manager

Qualifications:







(g) Evaluation of concrete strength





2 Position: Supervisor

Qualifications:


performing the below fresh and hardened concrete tests:







strength tests






content)

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3 Position: Technician (compulsory if requested by the Engineer)

Qualifications:

(a) The technician shall be capable of satisfactorily performing the below fresh and

hardened concrete tests:







strength tests






content)




20.5 CONTRACTORS

20.5.1 Concrete Construction Department

1 Position: Site Engineer

Qualifications:

(a) The site engineer shall be capable of satisfactorily reading, understanding and








strength tests


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2 Position: QC Manager/ QC Engineer/ Material Engineer

Qualifications:







(g) Specifying and evaluating of concrete strength





20.6 CONSULTANTS

20.6.1 Site Supervision Department

1 Position: Site Inspector/ Material Inspector

Qualifications:

(a) The site engineer shall be capable of satisfactorily reading, understanding and







strength tests


20.6.2 Site Supervision / Design Office Department

1 Position: Material Engineer

Qualifications:





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(g) Specifying and evaluating of concrete strength





END OF PART