Gasco Dgs 1783-002 Rev 2 Concrete Construction

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ABU DHABI GAS INDUSTRIES LTD. (GASCO)

CONCRETE CONSTRUCTION

DGS 1783-002 REV 2

TABLE OF CONTENTS

1. GENERAL .................................................................................................................................................................. 4

1.1 INTRODUCTION ............................................................................................................................................................. 4 1.2 PURPOSE ..................................................................................................................................................................... 4 1.3 DEFINITIONS ................................................................................................................................................................ 4

2. CODES AND STANDARDS.......................................................................................................................................... 4

3. REFERENCE DOCUMENTS ......................................................................................................................................... 7

4. DOCUMENT PRECEDENCE ........................................................................................................................................ 7

5. SPECIFICATION DEVIATION/CONCESSION CONTROL ................................................................................................ 8

6. QUALITY ASSURANCE/QUALITY CONTROL ............................................................................................................... 8

7. DOCUMENTATION ................................................................................................................................................... 8

7.1 MATERIAL SOURCES ...................................................................................................................................................... 8 7.2 MATERIAL DETAILS........................................................................................................................................................ 8

8. SUBCONTRACTORS/VENDORS ................................................................................................................................. 9

9. HANDLING ............................................................................................................................................................... 9

10. SURVEYING .......................................................................................................................................................... 9

11. EXISTING SERVICES AND FACILITIES ...................................................................................................................... 9

12. EXCAVATION AND BACKFILL ............................................................................................................................... 10

13. SUBGRADE PREPARATION .................................................................................................................................. 10

14. BLINDING ........................................................................................................................................................... 10

15. MATERIALS......................................................................................................................................................... 10

15.1 CONCRETE ................................................................................................................................................................. 10 15.2 ANCHOR BOLTS .......................................................................................................................................................... 10 15.3 WATERSTOPS ............................................................................................................................................................. 11 15.4 EMBEDMENTS ............................................................................................................................................................ 11 15.5 STEEL REINFORCEMENT ................................................................................................................................................ 11 15.6 EXPANSION JOINTS ...................................................................................................................................................... 12 15.7 FORMS ..................................................................................................................................................................... 12 15.8 CURING COMPOUND ................................................................................................................................................... 12 15.9 PROTECTIVE COATINGS - ABOVE AND BELOW GROUND ........................................................................................................ 13

16. FORMWORK ....................................................................................................................................................... 16

17. FIXING OF REINFORCEMENT ............................................................................................................................... 19

18. FIXING OF MISCELLANEOUS ITEMS AND EMBEDMENTS ..................................................................................... 20

18.1 ANCHOR BOLTS........................................................................................................................................................... 20 18.2 WATERSTOPS ............................................................................................................................................................. 21 18.3 EMBEDMENTS AND EXPANSION JOINTS ............................................................................................................................ 21

19. CONCRETE PREPARATION AND PLACEMENT ...................................................................................................... 21

20. FINISHING .......................................................................................................................................................... 25

20.1 UNFORMED SURFACES ................................................................................................................................................. 25 20.2 FORMED SURFACES ..................................................................................................................................................... 26

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21. CURING .............................................................................................................................................................. 28

21.1 GENERAL ................................................................................................................................................................... 28 21.2 CURING PERIOD .......................................................................................................................................................... 28 21.3 CURING OF TOP SURFACES ............................................................................................................................................ 28 21.4 CURING OF VERTICAL SURFACES ..................................................................................................................................... 28 21.5 CURING OF INACCESSIBLE AREAS .................................................................................................................................... 28

22. CONCRETE REPAIR .............................................................................................................................................. 29

23. PROTECTIVE COATING APPLICATION .................................................................................................................. 29

24. ACCEPTANCE ...................................................................................................................................................... 29

25. PROTECTION OF PROPERTY AND PERSONNEL .................................................................................................... 29

26. CLEAN UP ........................................................................................................................................................... 30

27. CATHODIC PROTECTION FOR STEEL IN CONCRETE .............................................................................................. 30

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1. GENERAL

1.1 Introduction

The CONTRACTOR shall provide the services required for the concrete work.

1.2 Purpose

This specification provides minimum installation requirements for the concrete work.

1.3 Definitions

Where used in this specification, the following terms shall have the meanings indicated below unless otherwise clearly indicated by context of their use.

COMPANY: ABU DHABI GAS INDUSTRIES LTD. (GASCO)

CONCESSION REQUEST: A deviation requested by the CONTRACTOR or VENDOR, usually after receiving the contract package or purchase order. Often, it refers to an authorization to use, repair, recondition, reclaim, or release materials, components or equipment already in progress or completely manufactured but which does not meet or comply with COMPANY requirements. A CONCESSION REQUEST is subject to COMPANY approval.

CONTRACTOR: the party(s) which carries out all or part of the design, engineering, procurement, construction, commissioning or management of the PROJECT.

PROJECT: (To be defined)

MANUFACTURER/VENDOR/SUPPLIER: The party(s) which manufactures and/or supplies the material/equipment, and provides technical documents/drawings and services to perform the duties specified by COMPANY/CONTRACTOR.

SUBCONTRACTOR/SUBVENDOR: The party(s) which carries out all or part of the design, procurement, installation and testing of the System(s) as specified by the CONTRACTOR/VENDOR.

DESIGNER: The Engineering Division of the CONTRACTOR or the Consultant which performs the design of the element in question.

PROJECT MANAGEMENT TEAM (PMT): The COMPANY authorized party responsible for the overall day-to-day execution of the Project. PMT is to serve as a Liaison between COMPANY and the CONTRACTOR(S) on the Project.

SHALL: Indicates a mandatory requirement

SHOULD: Indicates that the requirement is strongly recommended to be adhered to

DRAWINGS: Drawings provided by the CONTRACTOR/ VENDOR.

2. CODES AND STANDARDS

The following Codes, Standards and Specifications apply to this Specification. When an edition date is not indicated for a Code or Standard, the latest edition and addenda in force at time of contract award shall apply. Material and equipment shall be as specified or an equal approved by the COMPANY.

Where there are conflicts between the requirements of different Specifications, Codes and Standards the most stringent criteria shall apply.

BRITISH STANDARDS INSTITUTION (BSI)

BS 2571 General Purpose Flexible PVC compounds for moulding and extrusion

BS 4449 Steel for the reinforcement of concrete Weldable reinforcing steel Bar, coil and de-coiled product

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BS 4482 Steel wire for the reinforcement of concrete products

BS 4483 Steel fabric for the reinforcement of concrete

BS 8110 Structural use of Concrete

BS 8666 Scheduling, dimensioning, bending and cutting of steel reinforcement for concrete

BS EN 1008 Mixing water for concrete

BS EN ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles. Specifications and test methods

BS EN ISO 8501 Preparation of steel substrates before application of paints and related products

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM A36/A36M Standard Specification for Carbon Structural Steel

ASTM A123/A123M Standard Specification for Zinc (Hot-Dip Galvanizing) Coatings on Iron and Steel Products

ASTM A143/A143M Practice for Safeguarding against Embrittlement of Hot-Dip Galvanized Structural Steel Products and Procedure for Detecting Embrittlemet

ASTM A153/A153M Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware

ASTM A194/A194M Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both

ASTM A320/A320M Alloy/steel Bolting Materials for Low-Temperature Service

ASTM A563M Carbon and Alloy Steel Nuts [Metric]

ASTM A615/A615M Specification for Deformed and Plain Carbon Steel Bars for Concrete Reinforcement

ASTM C171 Specification for Sheet Materials for Curing Concrete

ASTM C309 Liquid Membrane-Forming Compounds for Curing Concrete

ASTM C531 Test method for Linear Shrinkage and Coefficient of Thermal Expansion of Chemical Resistant Mortars, Grouts, Monolithic Surfacings and Polymer Concretes

ASTM C642 Test Method for Density, Absorption, and Voids in Hardened Concrete

ASTM C672/C672M Test Method for Scaling Resistance of Concrete Surfaces Exposed to Deicing Chemicals

ASTM C836 Specification for High Solids Content, Cold Liquid-Applied Elastomeric Waterproofing Membrane for Use with Separate Wearing Course

ASTM C882/C882M Test Method for Bond Strength of Epoxy-Resin Systems Used with Concrete by Slant Shear

ASTM C920 Specification for Electrometric Joint Sealants

ASTM C944/C944M Test Method for Abrasion Resistance of Concrete or Mortar Surfaces by the Rotating-Cutter Method

ASTM D36 Test Method for Softening Point of Bitumen Ring-and-Ball Apparatus)

ASTM D395 Test Methods for Rubber Property-Compression Set

ASTM D412 Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers Tension

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ASTM D543 Test Methods for Index of Refraction of Transparent Organic Plastics

ASTM D570 Test Method for Water Absorption of Plastics

ASTM D638 Test Method for Tensile Properties of Plastics

ASTM D882 Standard Test Method for Tensile Properties of Thin Plastic Sheeting

ASTM D903 Standard Test Method for Peel or Stripping Strength of Adhesive Bonds

ASTM D994 Specification for Preformed Expansion Joint Filler for Concrete (Bituminous Type)

ASTM D1000 Test Methods for Pressure-Sensitive Adhesive Coated Tapes Used for Electrical and Electronic Applications

ASTM D1004 Standard Test Method for Initial Tear Resistance of Plastic Film and Sheeting

ASTM D1751 Structural Construction (Non-Extruding and Resilient Bituminous Types)

ASTM D1876 Standard Test Method for Peel Resistance of Adhesives (T-Peel Test)

ASTM D2240 Test Method for Rubber Property-Durometer Hardness

ASTM D4073 Test Method for Tensile-Tear Strength of Bituminous Roofing Membranes

ASTM D4260 Practice for Acid Etching Concrete

ASTM D4262 Test Method for PH of Chemically Cleaned or Etched Concrete Surfaces.

ASTM D4263 Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method

ASTM D4541 Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers

ASTM E96/E96M Test Method 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

ASTM F1554 Specification for Anchor Bolts, Steel, 36, 55 and 105-ksi Yield Strength

ASTM F436M Hardened Steel Washers [Metric]

ASTM F568M Carbon and Alloy Steel Externally Threaded Metric Fasteners

AMERCIAN CONCRETE INSTITIUTE (ACI)

ACI 207.1 R Guide to Mass Concrete

ACI 304.2R Placing concrete by Pumping Methods

ACI 305.1 Hot Weather Concreting

ACI 308R Guide to Curing Concrete

ACI SP-66 ACI Detailing Manual

ACI 117 Tolerances for Concrete Construction and Materials and Commentary

ACI 318 Building Code Requirements for Structural Concrete and Commentary

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ADDITIONAL STANDARDS

ASME B1.1 Unified Inch Screw Threads (UN and UNR Thread Form)

AASHTO T259 Method of Test for Resistance of Concrete to Chloride Ion Penetration

INTERNATIONAL ORGANISATION FOR STANDARDIZATION

ISO 9001 Quality Management Systems Requirements

ISO 9004 Managing for the sustained success of an organization - A quality management approach

AMERICAN WELDING SOCIETY (AWS)

AWS D1.4/D1.4M Structural Welding Code - Reinforcing Steel

3. REFERENCE DOCUMENTS

The following reference documents, to the extent specified herein, form a part of this specification. When an edition date is not indicated for a document, the latest edition in force at the time of contract award shall apply.

Design General Specifications:

DGS 1486-002 Excavation and Backfill for Underground Installations

DGS 1783-001 Concrete Supply

DGS 1783-003 On-Site Testing Laboratory

DGS 6600-010 Painting

DGS 1674-001 Design, Installation, Commissioning and Monitoring of Cathodic Protection for Plant Facilities

DGS 1300-175 Galvanizing

DGS 1882-001 Structural Design Basis

Standard Drawings:

STD-1781-002-001 Anchor Bolts Materials Fabrication Marking

STD-1781-002-002 Anchor Bolts Type T

STD-1781-002-003 Anchor Bolts Type R

STD-1781-002-004 Anchor Bolts Type S

STD-1781-002-005 Anchor Bolts Type Z

STD-1781-002-006 Membrane Protection to Concrete Foundations and Pedestals

Other Documents:

CIRIA Publication C577 Guide to the Construction of Reinforced Concrete in the Arabian Peninsula

CIRIA Publication C660 Early age thermal cracks control in concrete

4. DOCUMENT PRECEDENCE

It shall be the CONTRACTORS responsibility to be, or to become, knowledgeable of the requirements of the referenced Codes and Standards.

The CONTRACTOR shall notify the COMPANY of any apparent conflict between this specification, the related data sheets, the Codes and Standards and any other specifications noted herein.

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Resolution and/or interpretation precedence shall be obtained from the COMPANY in writing before proceeding with the design/manufacture.

In case of conflict, the order of precedence shall be:

Purchase Order or Contract including Project Drawings and Specifications

Design General Specifications and Standards

Industry Codes and Standards

5. SPECIFICATION DEVIATION/CONCESSION CONTROL

Deviations from this specification are only acceptable where the CONTRACTOR has listed in his quotation the requirements he cannot, nor does not wish to comply with, and the COMPANY has accepted in writing the deviations before the order is placed.

In the absence of a list of deviations, it will be assumed that the CONTRACTOR complies fully with this specification.

Any technical deviations to the Purchase Order and its attachments including, but not limited to, the Design General Specifications shall be sought by the CONTRACTOR only through CONCESSION REQUEST format. CONCESSION REQUESTS require COMPANYs review/approval, prior to the proposed technical changes being implemented. Technical changes implemented prior to COMPANY approval are subject to rejection.

6. QUALITY ASSURANCE/QUALITY CONTROL

The CONTRACTOR shall have in effect at all times, a QA/QC program which clearly establishes the authority and responsibility of those responsible for the quality system. Persons performing quality functions shall have sufficient and well defined authority to enforce quality requirements that initiate, identify, recommend and provide solutions to quality problems and verify the effectiveness of the corrective action.

CONTRACTORs Quality Management Systems shall comply with all the requirements of ISO 9001 Quality Management Systems Requirements and ISO 9004 Managing for the sustained success of an organization A quality management approach.

A copy of the CONTRACTORs QA/QC program shall be submitted to the COMPANY with its quotation for review and concurrence prior to award. If CONTRACTORs QA/QC program is ISO 9000 certified, then only a copy of the ISO 9000 certificate is required. In addition, if VENDORS facility is ISO certified, QA audit requirements will be waived in favor of ISO 9000 registrar audits, unless the COMPANYs trend analysis program indicates areas of concern.

The CONTRACTOR shall identify in documents to its VENDORs and SUBCONTRACTORs all applicable QA/QC requirements imposed by the COMPANY, and shall ensure compliance. On request, CONTRACTOR shall provide objective evidence of its vendor and subcontractor QA/QC activities.

7. DOCUMENTATION

7.1 Material sources

Refer to specification for concrete supply n dgs 1783 001. All material sources shall be approved by company. All materials must be selected from the approved sources.

7.2 Material Details

The contractor shall submit full details of each proposed material in sufficient time to allow detailed company review.

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Submittals shall include the following:

MANUFACTURER's details

Fully detailed data sheet showing all chemical and physical information.

Recent test results (not more than 3 months old)

Detailed technical assessment

Details of MANUFACTURER's Quality Assurance System.

Details of MANUFACTURER's Quality Control procedures.

The CONTRACTOR shall submit an Affidavit of Compliance before beginning construction. The affidavit shall confirm that all material meets the requirements of this Specification.

8. SUBCONTRACTORS/VENDORS

The CONTRACTOR shall assume unit responsibility and overall guarantee for the concrete construction.

It is the CONTRACTORs responsibility to enforce all Purchase Order and Design General Specification requirements on its SUBCONTRACTORS / VENDORS.

The CONTRACTOR shall submit all relevant SUBCONTRACTORS / VENDORS engineering data to the COMPANY.

The CONTRACTOR shall obtain and transmit all SUBCONTRACTORS / VENDORS warranties to the COMPANY.

9. HANDLING

(NOT APPLICABLE)

10. SURVEYING

1. The contractor shall extend all lines and grades as required for the work from bench marks and base lines.

2. The contractor shall co-operate in preserving all control bench mark monuments and stakes, and other markers establishing lines, elevations, slopes, etc. The CONTRACTOR/ SUBCONTRACTOR shall replace at no cost to the company, monuments, stakes, and other markers which he disturbs or destroys during the course of his work.

3. The company may check lines, grades, and locations established by the contractor. The contractor shall be responsible for the accuracy of their work.

11. EXISTING SERVICES AND FACILITIES

1. Before beginning work, the contractor shall ascertain the nature and location of all existing above and underground services and facilities on site and in adjacent areas by inspecting available plans or, if necessary, by hand excavation. The company will make available, for review, any existing layout drawings which cover the area of work. Contractor will be responsible for confirmation, or otherwise, of any such information given.

2. The contractor shall take every precaution including providing temporary supports, bridging, shoring, and safety barriers to protect the existing services and facilities from damage or interference during construction. The contractors precautions shall be subject to approval by the company.

3. The contractor shall notify the company in writing if any previously unrecorded services or other objects are discovered before or during construction. The contractor shall record and give to the company accurate description, dimensions, location, and elevations related to reference datum and other relevant details of such services.

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4. A certificate or permit shall be obtained from the company, indicating that services have been cut off and made safe and specifying any services or other facilities adjacent to site including related safety aspects and measures which must be maintained during the execution of the work. The contractor shall confirm independently that service have in fact been cut off and made safe.

5. When the contractor needs to block drainage paths during construction, they shall provide temporary or permanent alternate routing during construction and restore the drainage to the satisfaction of company when construction is complete.

6. When the contractor accidentally damages existing structures or facilities, they shall repair or replace them at no cost and to the satisfaction of company.

12. EXCAVATION AND BACKFILL

All excavation and backfill work associated with the concrete work shall be in accordance with the specification for excavation and backfill for underground installations, DGS 1486-002 and the site specific geotechnical report.

13. SUBGRADE PREPARATION

All subgrade preparation work associated with the concrete work shall be in accordance with the Specification for Excavation and Backfill for Underground Installations, DGS 1486-002 and the site specific geotechnical report.

14. BLINDING

1. All concrete works, except concrete paving, shall be placed on a minimum 75 mm thickness of blinding concrete. The extent of the blinding concrete shall be such that all member protective coating can be applied in accordance with the manufacturers recommendations.

2. The sub-grade for blinding shall be uniform and smooth and have no indentations in the surface to receive concrete. A vapor barrier of 1000 gauge (0.25mm) polyethylene shall be applied on the sub-grade and shall be installed and sealed at laps in strict accordance with MANUFACTURER's instructions.

15. MATERIALS

15.1 Concrete

15.1.1 Concrete shall be in accordance with the specification for concrete supply, DGS 1783-001.

15.1.2 Concrete testing shall be in accordance with the specification for on-site testing laboratory, DGS 1783-003.

15.2 Anchor Bolts

15.2.1 Anchor bolt material shall be in accordance with ASTM F1554. Anchor bolts design and types shall be as per the following standard drawings:

STD-1781-002-001 Anchor Bolts Materials Fabrication Marking

STD-1781-002-002 Anchor Bolts Type T

STD-1781-002-003 Anchor Bolts Type R

STD-1781-002-004 Anchor Bolts Type S

STD-1781-002-005 Anchor Bolts Type Z

15.2.2 Nuts shall be heavy hex conforming to ASTM A563M. All anchor bolts shall be fitted with two nuts.

15.2.3 Washers shall be plain hardened round washers conforming to ASTM F436M.

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15.2.4 Nuts and bolts shall have cut threads conforming to ASME B1.1. Bolt threads shall have class 2a fit, and nut threads shall have class 2b fit.

15.2.5 Thread series for bolt diameters up to and including 100 mm shall be unified coarse.

15.2.6 When required, anchor bolts shall be placed in sleeves. Sleeves shall be manufactured of schedule 40 pipe, polystyrene or neoprene as indicated on the design drawings.

15.2.7 Anchor bolts, nuts, washers and sleeves shall be in accordance with the type, dimensions and details indicated on the drawings.

15.2.8 Bolts, nuts and washers shall be hot-dipped galvanized in accordance with ASTM A143 and ASTM A153. Bolts shall be rethreaded and nuts retapped after galvanizing.

15.2.9 Bolts, nuts and washers shall be cleaned and the threads shall be greased or oiled before shipment.

15.2.10 Chemical adhesive anchors, where indicated on the drawings, shall use an epoxy resin adhesive with suitable hardener. Material approval shall be obtained from the company prior to incorporating into the work. Contractor shall develop applicable standard to companys approval.

15.3 Waterstops

15.3.1 Waterstops shall be factory preformed ribbed type 10 mm minimum thickness in accordance with BS 2571 for PVC or ASTM D395 and ASTM D2240 for rubber as specified on the drawings.

15.3.2 Minimum width of waterstop shall be 230 mm for concrete section greater than 200mm wide and 150mm for concrete section less than 200 mm.

15.4 Embedments

15.4.1 Embedment material shall be in accordance with ASTM A36/A36M or as indicated on the drawings.

15.4.2 Embedment material shall be hot-dipped galvanized in accordance with ASTM A123/A123M or BS EN ISO 1461, and Design General Specification for Galvanizing, DGS 1300-175 or painted in accordance with Design General Specification for Painting DGS 6600-010 as per COMPANY approval.

15.5 Steel Reinforcement

15.5.1 Steel reinforcement material shall be in accordance with Design General Specification for Structural Design Basis, DGS 1882-001.

15.5.2 Steel reinforcement shall be cut and bent accurately to the dimensions and shapes shown on the drawings in accordance with BS 8666 or ACI SP-66. No heating or welding shall be allowed.

15.5.2.1 All cutting and bending of the steel reinforcement shall be complete before final positioning prior to concrete placement.

15.5.2.2 All cutting and bending of the steel reinforcement shall be carried out at a specially commissioned bar bending shop established at the site under control of contractor for production and quality.

15.5.3 The contractor shall provide copies of the manufacturer's certificates of test results for each batch of reinforcement steel ordered and supplied to the site. Each batch held at the site shall be identified and traceable to such certificates.

15.5.4 Reinforcing spacers shall be used to insure the correct spacing of the reinforcing from the outside edge of the structural designed section. The spacers shall be company approved proprietary reinforcement spacers manufactured from an inert material (such as UPVC). Concrete spacers shall not be used, even when they are cast from the same design mix as the actual concrete foundation.

15.5.5 Reinforcing spacers between reinforcing layers shall consist of steel reinforcing cut and bent to insure the tolerances as specified in BS 8666 or ACI SP-66.

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15.5.6 Fabric reinforcement shall comply with the requirements of BS 4483 or ASTM A184, made with cold reduced steel wire complying with BS 4482. The weights and dimensions shall be as indicated on the drawings and shall be supplied in flat sheets.

Rolls of fabric reinforcement will not be accepted.

15.5.6.1 Fabric reinforcement shall be bent accurately to the required shapes before the fabric is laid in position.

15.5.6.2 All bending and cutting shall be done cold and no heating or welding shall be allowed.

15.5.7 All reinforcement shall be stored under cover on timber over concrete or steel crib support suitably spaced and of sufficient height to keep the steel at least 200 mm above ground level. Reinforcement shall be protected from all aggressive elements, including chlorides and moisture, by covering with suitable protection material. It shall be neatly separated in sizes and clearly marked with its diameter.

15.6 Expansion Joints

15.6.1 Joint filler shall be premolded asphalt impregnated fiberboard per ASTM D994, or premolded nonextruding type material per ASTM D1751.

15.6.2 Joint sealer for paving and other horizontal applications shall be elastic type material conforming to ASTM C920 Grade P, Class 25, use T (or else I, if submerged in liquid). Primer shall be applied as recommended by the MANUFACTURER. Sealer and primer shall be installed in strict accordance with the MANUFACTURERs instructions.

15.6.3 Joint sealer for vertical or overhead joints shall be elastic type material conforming to ASTM C920 Grade NS, Class 25, use NT (or use I, if submerged in liquid). Primer shall be applied as recommended by the MANUFACTURER. Sealer and primer shall be installed in strict accordance with the MANUFACTURERs instructions.

15.7 Forms

15.7.1 Form faces shall be made of marine plywood, steel or GRP. Plywood materials shall be new when brought to the construction site and shall be properly coated, protected, and maintained throughout their use. Materials that are damaged, cracked, weathered or otherwise unsuited for producing smooth, uniformly textured formed surfaces shall be rejected.

15.7.2 Internal form ties shall be permanently embedded metal non cavity type and shall have removable ends. Outer ends of the permanently embedded portions of form ties shall be at least 75 mm from adjacent outer concrete faces. Non fabricated wire shall not be used.

15.7.3 The forms shall be coated with approved chloride free form release oil.

15.7.4 Insulated formwork to control concrete temperature differentials in thick sections shall be used where determined necessary by trial, calculation or whenever directed by the company.

15.8 Curing Compound

15.8.1 Curing compound shall be white-pigmented in accordance with ASTM C 309 (type ii) and shall be accompanied by a certificate from an approved institute, stating:

Exact range and method of application

Physical and chemical composition

Positive and negative side effects

Proportioning at application

No chlorides

Compatibility with proposed surface treatment

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The efficiency of the curing membrane shall be demonstrated by testing trial panels for absorption using Senbetta and Scholer method.

The use of curing compound shall be restricted to areas where the use of water is not practical.

15.9 Protective coatings - above and below ground

All concrete, except the top side of general paving, shall be coated per the appropriate system described below.

All membranes/coatings shall be applied at not less than seven days and not more than 28 days after curing is completed.

Concrete surfaces shall be dry and free from contamination such as oil, grease, loose particles, surface laitance, form release agents and curing compounds. Concrete surfaces shall be lightly grit blasted or power washed if/as required by the coating MANUFACTURER.

Honey combing, blowholes, hairlines cracks and other surface imperfections shall be filled and repaired prior to any coating application.

Where concrete will be exposed to aggressive chemicals such as acids, brine, hot fumes, etc., special protection systems such as acid resistant brick or epoxy coatings will be specified on the Engineering drawings.

All coating systems and extents of coating will be shown on the Engineering drawings.

The coating MANUFACTURER shall submit a detailed installation procedure that includes the requirements for surface preparation, priming, application, curing and protection.

If the Concrete Construction SUBCONTRACTOR does not have a minimum of 5 years experience in the preparation and installation of the protective concrete coatings, then the Concrete Construction SUBCONTRACTOR shall subcontract the application of all concrete coatings to a Specialty Applicator SUBCONTRACTOR, who has above-specified experience and capability.

All coatings shall be installed in strict accordance with the MANUFACTURERs instructions. This shall include the MANUFACTURERs recommendations for surface preparation, priming, application, curing and protection.

A Vendor representative of the coating MANUFACTURER shall visit the site prior to the commencement of the concrete coating application, for meetings with the Concrete Construction SUBCONTRACTOR and Specialty Applicator SUBCONTRACTOR (if the Concrete Construction SUBCONTRACTOR does not have the above-specified experience and capability) to ensure that the MANUFACTURERs recommendations and instructions are understood and followed.

All submissions of membrane and coating shall be accompanied by independent test certification that verifies the properties of the submitted product(s).

The coatings of this specification may not apply to concrete buildings. For the coating of buildings refer to the applicable architectural specification.

15.9.1 Below ground protective coating

All below ground concrete shall be fully encapsulated with one layer of a minimum 1.5mm thick self-adhesive rubber/bitumen high density polyethylene laminated waterproof membrane.

The membrane shall be capable of resisting tears and punctures from normal construction activities, rebar chairs, concrete spacer blocks, etc. and capable of being exposed to weather and UV light for up to 30 days prior to casting concrete.

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The membrane shall have the following minimum properties:

Property Standard Limit

Elongation of Film ASTM D638 170%

Tear resistance :

Longitudinal

Transverse

ASTM D4073

270N/mm

270N/mm

Adhesion to primed concrete ASTM D1000 >1.8 N/mm

Adhesion to self - Lap Adhesion ASTM D1000 >1.8 N/mm

Puncture resistance ASTM E154 Min 225N

Moisture Vapor Transmission ASTM E96 1000C

Tensile Strength:

Longitudinal

Transverse

ASTM D638

6.3 N/mm

4.8 N/mm

The membrane shall extend to 50 mm below the level of high point of finished grade or paving as shown on STD-1781-002-006.

All foundations shall be installed on a support/membrane system consisting of the following layers (placed in same sequence):

Vapor barrier, polyethylene of 1000 gauge (0.25mm) thick

75mm minimum thick layer of blinding concrete

1.5mm membrane as described above

30mm layer of screed concrete.

When there is a valid reason and after obtaining the COMPANY approval, the screed could be replaced with equivalent hard (incompressible), polypropylene based (or similar) protection board (not less than 5mm thick).

All below ground membranes and coatings shall be protected from damage due to construction activities and backfilling by covering with a protection board of 3.5 mm bitumen impregnated fiberboard or 12 mm thick bitumen impregnated soft board.

Small miscellaneous foundations such as stair/ladder footings, non-equipment footings less than 2m by 1m in plan, and non-hydrocarbon piping service pipe sleepers less than 300mm wide by 500 mm overall depth shall be coated with 500 microns Dry Film Thickness (D.F.T) non-solvented coal tar epoxy.

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The coating shall have the following minimum properties:


Solids Content 100%

Specific Gravity 1.35

Water Absorption ASTM D570 Nil

Adhesion Strength ASTM D4541 >1.0 N/mm

Abrasion resistance ASTM C944 0.1 g

Linear Shrinkage ASTM C531 50%

Reduction in chloride

ion penetration

AASHTO T259 > 92%

Moisture Vapor Transmission 45g/m2 24hrs

Reduction in water absorption ASTM C642 >82%

CO2 diffusion resistance equivalent thickness of concrete (Taywood Method)

>500mm

Chloride ion diffusion coefficient

(Taywood Method)

No chloride diffusion after 60 days

Bond Strength ASTM D4541 >1.0 N/mm2

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For areas subject to chemical / hydro carbon spillage, the concrete surfaces shall be protected with an epoxy coating system consists of the following:

a. Primer coat compatible with subsequent coats as per MANUFACTURER recommendations.

b. One coat of a solvent free Epoxy coating to a D.F.T. of 200 microns

c. Two coats of chemical and U.V. resistant polyurethane resin coating to D.F.T. of 75 microns each coat.

The finished coating shall be pinhole free and have a total minimum D.F.T. of 350 microns.

The coating shall have the following minimum properties:

Solvent free Epoxy coating:


Solid contents 100%



Resistance to chloride ion

penetration (Taywood Method)

100%

Resistance to CO2 diffusion No Carbonation

Polyurethane top coating:


Solid contents >50%



Resistance to chloride ion

penetration (Taywood Method)

100%

Resistance to CO2 diffusion 1.0 x 10-7

cm2/s

Chemical Resistance Good.

15.9.3 Testing

All testing of the materials used in the concrete mixes as well as the testing of fresh and hardened concrete will be performed by the Testing Laboratory.

For the requirements of the testing laboratory and the type and frequency of testing refer to Design General Specification for On-Site Testing Laboratory, DGS 1783-003.

16. FORMWORK

1. The CONTRACTOR/SUBCONTRACTOR shall provide details of the methods and materials proposed for formwork for each section of the work. Details of formwork to produce special finishes are to be submitted for approval in writing to the company before any materials are brought on to the site.

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2. Forms shall be constructed from sound material of sufficient strength, properly braced, strutted and shored to ensure rigidity throughout the placing and compaction of the concrete without visible deflection. All formworks shall be water tight to prevent grout loss.

3. Formwork shall be constructed to provide the correct shape, lines and dimensions of the concrete shown on the drawings. Due allowance shall be made for any deflection which will occur during the placing of concrete within the forms.

4. Forms shall be so constructed that they can be removed without shock or vibration to the concrete.

5. The design and construction of formwork shall be in accordance with ACI 301 and ACI 347 or BS Standards.

6. Chamfer strips 25 mm x 25 mm shall be placed in forms to bevel all salient edges and corners except bottom edges of foundations.

7. Temporary openings shall be provided where necessary to drain away water and to assist in the removal of rubbish.

8. Before concrete is placed, all formwork and supports shall be thoroughly cleaned.

9. The formwork shall be coated with an approved chloride free form release oil and all excess shall be carefully removed. Form release oil shall not be allowed to come into contact with concrete already placed, with reinforcement or other embedded items.

10. Concrete shall not be placed until the relevant formwork has been inspected and approved. This shall not relieve the contractor from the requirements as to soundness, finish and accuracy specified elsewhere.

11. Formwork shall be constructed so that the concrete surfaces will conform to the tolerance limits listed in table below:

Under no circumstances shall concrete cover be reduced below the minimum given in this specification.

Tolerances for Formed Surfaces

1. Variation from plumb:

A. In the lines and surfaces of columns, piers, walls, and in arises:

In any 3000 mm of length 7 mm

Maximum for the entire length 20 mm

B. For exposed corner columns, control-joint grooves, and other conspicuous lines:

In any 6000 mm length 7 mm


2. Variation from the level or from the grades specified in the contract documents:

A. In slab soffits, ceilings, beam soffits and in arises, measured before removal of supporting shores:

In any 3000 mm of length 7 mm

In any bay or in any 6000 mm length 9 mm


B. In exposed lintels, sills, parapets, horizontal grooves, and other conspicuous lines:

In any bay or in 6000 mm length 7 mm


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3. Variation of the linear building lines from established position in plan and related positions of columns, walls, and partitions:

In any bay 10 mm

In any 6000 mm length 10 mm


4. Variation in the sizes and location of sleeves, floor openings, and wall openings 7 mm.

5. Variation in cross-sectional dimensions of columns and beams and in the thickness of slabs and walls:

Minus 7 mm

Plus 13 mm

6. Footings

A. Variations in dimensions in plan:

Minus 13 mm

Plus 30 mm

B. Misplacement or eccentricity:

2 per cent of the footing width in the direction of misplacement but not more than 30 mm

C. Thickness

Decrease in specified thickness 5 percent

Increase in specified thickness 5 percent

7. Variation in steps:

A. In a flight of stairs:

Riser 3 mm

Tread 7 mm

B. In consecutive steps:

Riser 2 mm

Tread 3 mm

Tolerances apply to concrete dimension only and not to positioning of vertical reinforcing steel, dowels or embedded items.

12. The formwork shall be removed in accordance with ACI 301 and ACI 347 or BS 8110, part I, section 6, except as stated hereunder.

13. Forms shall be removed in such a manner as to not damage the concrete. No forms shall be removed until the concrete has gained sufficient strength to support itself.

14. At no stage shall the loosening or removal of formwork interrupt or prevent the immediate and continuous curing of the concrete.

15. Centers and props may be removed when the member being supported has gained sufficient strength to carry itself and the load to be imposed on it with an acceptable factor of safety.

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16. The following table provides the minimum periods which must elapse between the completion of the concreting operations and the removal of formwork.

17. The following minimum periods before striking shall be adhered to:

Vertical sides of beams, walls, columns - lift not exceeding 1.2 m

24 hrs.

Construction joints 24 hrs.

Vertical sides of beams, walls, lift exceeding 1.2 m 36 hrs.

Tank walls 48 hrs.

Soffits of main slabs (Props left under) 6 days

Soffits of main beams (Props left under) 14 days

Beams and main slabs(Removal of props - depending on back propping arrangement and calculations)

21 days

After removal of formwork no remedial works shall be attempted until the work has been inspected by the COMPANY.

18. Providing the concrete strength is confirmed by tests on cubes, cured and stored under the same environmental conditions, formwork supporting cast in-situ concrete may be struck when the cube strength is 25 MPa or twice the stress to which it will be subjected, whichever is the greater, provided that such earlier striking will not result in unacceptable deflections due to shrinkage, creep, etc. Self-supporting member forms may be removed after 7 days provided concrete strength is at least 70% of design strength as determined by field-cured specimens or other approved methods.

19. For thick sections, formwork shall be left in place for the required period determined by trial and/or calculation.

17. FIXING OF REINFORCEMENT

1. The reinforcement shall be positioned as indicated on the drawings. Spacers of suitable size shall be used to hold the reinforcement in position and provide the specified covers.

2. Corner bars in columns and beams shall be tied for the entire length of the lap so that the minimum cover requirements are achieved and the true alignment of the reinforcement is maintained.

3. Reinforcing shall be tied with 1.0 mm to 1.4 mm soft annealed galvanized wire.

4. Welding of reinforcement is prohibited unless noted on the drawings and approved by the company. Reinforcement with unauthorized welds shall be removed and replaced. Where indicated and approved the welds shall be tested to confirm adequacy. Where indicated and approved, the welding shall be in accordance with AWS D1.4, a weld procedure shall be submitted and approved, and the welds shall be tested to confirm adequacy

5. Robust plastic spacers shall be used in the following situations:

Walls

Elevated Slabs

Beams

Columns

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6. As a minimum, the concrete cover to the reinforcement shall be as specified herein. Cover is to the outside of all reinforcement.

APPLICATION MINIMUM CONCRETE COVER (mm)

Concrete cast against or permanently exposed to earth (all below grade structures)

75

Concrete exposed to weather (all above grade structures not enclosed by a temperature and humidity controlled building)

60

Concrete not exposed to weather (located within a temperature and humidity controlled building)

50

Notes:

1) Where any individual structural element falls within two or more categories then the most stringent criteria shall apply for the entire element.

2) Where there is limitation for the thickness of concrete elements (e.g. due to architectural design of building), the specified cover for concrete exposed to weather (60mm) and for concrete not exposed to weather (50 mm) could be reduced to 50 mm and 40mm respectively, after obtaining the necessary COMPANY approval.

Spacers shall be robust proprietary plastic spacers with a proven record of satisfactory performance in the field and which do not deform under the load of the reinforcement cage or displace and fail to provide the specified cover. Oversize spacers shall not be used to give more than the specified cover as this compromises the structural design of the member.

7. Required covers shall not be reduced by provision of protective coatings, membranes or by membrane protective screed.

8. The reinforcement steel condition shall conform to ACI 301 until the time of placement of concrete. If the reinforcement steel develops rust due to delay in placement of concrete it shall be sweep blasted using grit meeting the requirements of BS EN ISO 8501 Part 3 until it is free from loose mill scale or rust, oil, grease and other harmful matter immediately before inclusion in the works. The steel after cleaning shall remain within the limits of over and under weight allowed in BS 4449 or ASTM A615/A615M.

9. After installation all reinforcement exposed for more than 7 days shall be protected from contamination before and between pours by wrapping the formwork with suitable sheeting.

10. All reinforcement shall be washed clean, using water suitable for producing concrete, prior to placement of concrete.

11. All fabric shall be lapped for a minimum length of 300 mm unless otherwise stated on the drawings and tied together on both the longitudinal and transverse wires. All lapping shall be sufficient for the steel to develop its full strength.

12. If for any reason reinforcing bars are to be impounded or stored on site for long periods of time, a protective sacrificial coating or spray of corrosion inhibitor shall be used. If the coating will reduce the reinforcing/concrete bond, the coating shall be entirely removed prior to installation in the formwork.

18. FIXING OF MISCELLANEOUS ITEMS AND EMBEDMENTS

18.1 Anchor bolts

18.1.1 Anchor bolts shall be placed as indicated on the drawings before concreting.

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18.1.2 A template shall always be used to hold the anchor bolts in their correct position. The template shall be of rigid construction and fabricated from a suitable robust material. Anchor bolts shall not come in contact with the reinforcing steel.

18.1.3 Welding of anchor bolts to reinforcing steel shall not be permitted. Forging and heating of anchor bolts is not allowed.

18.1.4 Before installation, anchor bolts shall be de-greased by an approved method.

18.1.5 Unless otherwise specified by equipment/supplier, installation tolerances shall be as follows:

All anchor bolts shall be installed to 2 mm of their design position.

Anchor bolts shall be plumb to +/- 1:100.

Level tolerance to top of bolts shall be - 0 mm + 15 mm.

18.2 Waterstops

The method of joining waterstops shall be in full accordance with the manufacturer's recommendations and shall be performed in a controlled manner.

18.3 Embedments and expansion joints

18.3.1 All sleeves, inserts, anchors, expansion or isolation joint material, waterstops, anchor bolts, conduit, piping, nose angles, ladder rungs, and other embedded items shall be positioned accurately and supported against displacement. Voids in sleeves, inserts, and anchor slots shall be filled temporarily with readily removable material to prevent the entry of concrete into the voids.

18.3.2 Insert plates shall be of the material and size as indicated on the design drawings and shall be installed to the following tolerances.

18.3.3 Insert plates in the horizontal plane shall be installed so as to insure that the variation from level does not exceed 1.5 mm per 300 mm in either direction, and that the center of the surface of the insert is within 0.75 mm of the elevation shown on the drawings.

18.3.4 Insert plates whose least dimension is greater than 300 mm shall have sufficient weepholes to insure full bearing.

18.3.5 The center of the surface of the insert shall be within 1.5 mm of the vertical surface and within 3 mm of the location and elevation as shown on the drawings. Plumbness from top to bottom shall be 5 mm maximum.

19. CONCRETE PREPARATION AND PLACEMENT

1. Suitable means shall be provided to ensure that the temperature of the concrete when deposited does not exceed 30C. The temperature at the point of discharge for thick elements shall not exceed 24C. Thick elements shall be defined as any concrete member that has both plan and cross sectional dimensions exceeding one meter and containing a total volume exceeding six cubic meters.

Concrete placed in ambient air temperatures 27C or higher shall follow ACI 305.1, Specification for Hot Weather Concrete.

2. Concrete shall not be placed when the temperature of reinforcement or forms exceeds 35C, then items shall be sprayed with water complying with Design General Specification for Concrete Supply, DGS-1783-001 prior to placing concrete.

3. Suitable wind breaks shall be erected prior to pouring concrete. These shall be effective in shielding the concrete from drying winds during placing and for the full curing period if curing compound is used or until the wet curing system is in place.

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4. The heat of hydration shall not cause a temperature differential between the interior of the concrete and any outside face greater than 20 degrees c for placements where the least dimension is over 1 meter. The contractor shall develop methods and submit to the company for review and approval, to insure compliance.

5. 24 hours notice shall be given to the company before placing concrete.

6. Spaces to be occupied by concrete shall be clean and free from standing water.

7. Prior to pouring concrete against an adjacent face (construction joint), the face shall be clean and free of dirt, films, paint, coatings or other foreign matter. The reinforcement and water bars carefully cleaned and checked for integrity.

a. The adjacent face shall have all laitance to a depth of 2 to 3mm removed, so as expose the coarse aggregate.

b. Prior to concreting, the concrete surface shall be wetted so that water is not drawn into from the new concrete.

c. If surface retarder has been used on the concrete then the manufacturer shall be consulted to determine the length of time before the surface retarder is washed off.

8. The sequence of pours shall be agreed by the company.

9. The reinforcement and all embedded items shall be adequately secured to prevent movement during the placing or setting of the concrete.

10. The placing of concrete shall be in accordance with ACI 301 or BS 8110, part I section 6.

11. From June 1st until September 30th, approval shall be sought from the company before placing concrete at any time. If approval is received concrete shall not be placed or finished between the hours of 9 a.m. And 6:30 p.m. Concrete installation shall predominantly be at night.

12. Concrete shall be placed in the positions and sequences indicated on the drawings. All concrete shall be placed in forms.

13. The containers that convey the concrete shall at all times be kept clean and free from hardened or partially hardened concrete. Placing equipment shall be thoroughly cleaned at the end of each concreting operation.

14. Concrete, after being discharged from the mixer, shall be transported as rapidly as possible to its final position in the works by means which shall prevent adulteration, segregation, loss or contamination of the ingredients.

15. Concrete placing shall be completed as quickly and efficiently as possible. Curing of exposed concrete surfaces shall be immediately carried out as specified herein.

16. Concrete shall be deposited as nearly as practicable in its final position to avoid segregation due to rehandling or flowing. Concrete shall not be subjected to any procedure that will cause segregation. A competent steel fixer shall be in continuous attendance to adjust and correct the position of any reinforcement or metal item which may be displaced during concreting.

17. The concrete shall be placed and compacted in its final position in the form within 60 minutes of the water being added to the mix. This time of 60 minutes may be increased up to 90 minutes with the use of approved retarders at the discretion and approval of the company, depending on the necessity and circumstances. On no account shall additional water be added after the concrete has left the mixer pan. Re-tempering and further mixing shall not be permitted.

18. If section cannot be placed continuously construction joints shall be located as indicated on drawings or as permitted. Placing shall be carried on at such a rate that the concrete in place is still plastic when integrated with fresh concrete.

19. When a lift of concrete is interrupted and delayed for more than one hour, the surface of the unfinished concrete shall be thoroughly cleaned before fresh concrete is added. The first layer of new concrete placed shall not exceed 150 mm in depth and particular care shall be taken with compaction of this layer to ensure a good bond.

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20. If an interruption of more than one hour occurs, or is anticipated, during the concreting of a long horizontal member, a stop-end shall be installed at a location approved by the company to provide a clean vertical surface of the joint. Concreting within the stop-end shall be continued as far as possible to terminate with a horizontal surface at a suitable level or, preferably, to complete the full height of the pour.

With vertical sections, the unfinished concrete shall be finished off with a clean surface and left for 24 hours to set before any further concrete is placed. The surface shall then be thoroughly cleaned of all loose and foreign matter and laitance which may necessitate the temporary removal of the formwork before placing the remaining concrete.

21. In the case of an accidental interruption not specified in the drawings, the contractor must advise the company immediately. Such a situation may require partial or complete demolition.

22. The majority of concrete shall be placed by pumping per ACI 304.2R unless prevented by access requirements. Individual pours less than 2m3 may be placed by alternative means.

23. Pumping or pneumatic conveying equipment shall be of suitable kind with adequate pumping capacity. Pneumatic placement shall be controlled so that segregation does not occur in the discharged concrete. Concrete shall not be conveyed through pipe made of aluminum or aluminum alloy.

a. The contractor shall submit a method statement indicating full details of the pneumatic conveying equipment and operating system. Contractor shall ensure that pumping shocks shall not be transferred from the pipeline to the formwork, previously laid concrete or the structure.

b. The contractor shall demonstrate suitability of each concrete pump and system by submitting the following information for company approval:

Description of equipment;

Concrete mix design, including slumps at pump entry to pipe and at exit from pipe

Concrete temperature at exit from pipe.

Stand-by arrangements;

List of spare parts kept at Site.

Each pump shall deliver a continuous flow of concrete to the job without air pockets and other voids. Prior to use of a pump for construction activities CONTRACTOR shall carry out a full scale test.

c. The initial discharge of any pumped concrete shall be discarded and not be incorporated in the permanent works.

24. Riser and fixed pipe sections of the pneumatic conveying equipment shall be effectively insulated. After each operation the entire equipment shall be thoroughly cleaned.

25. When concrete is conveyed by chuting or pipes, the size and design of the plant and pipes shall be so selected 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 to produce the required consistency and without causing segregation of the ingredients. The delivery end of the chute or pipe shall be close to the point of deposit.

26. 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.

27. Where chutes are used to convey the concrete their slopes shall not be such as to cause segregation and suitable spouts or baffles shall be provided where necessary.

28. Concrete shall not be allowed to fall-freely from a height more than 1.5 m. Greater heights shall require an approved down pipe or chute.

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29. Except where otherwise permitted by the company concrete shall be compacted during placing by approved pattern internal vibrators. The vibrators shall operate at a frequency for continuous operation.

a. The performance of vibrators shall be such as to suit the working conditions and they shall be selected accordingly. For normal use they shall not be more than 75 mm diameter and will be subject to scrutiny by the company. The radius of influence shall be at least 300 mm. The vibrators shall be disposed in such a manner that the whole of the mass under treatment shall be adequately compacted at a speed commensurate with the supply of concrete from the mixers and to the satisfaction of the company. In confined areas, smaller vibrators will be required.

b. Internal vibrators should penetrate the full depth of the layer of concrete placed and compaction of newly placed concrete layer shall extend to upper 100 mm of the underlying layer to ensure a proper mixing.

c. Vibration is not to be applied directly or indirectly to concrete after the initial set has taken place.

d. External vibrators shall not be used without the permission of the company. The power supply to drive the vibrator(s) must be "spark free" etc., for use in live gas/oil plant.

e. Immersion vibrators shall be withdrawn slowly to prevent the formation of voids. Vibrators shall not be used to work the concrete along the forms, or in such a way as to damage formwork or other parts of the work, or displace the reinforcement.

f. Sufficient vibrators in serviceable condition shall be on site so that spare equipment is always available in the event of breakdowns.

g. Vibrators shall only be operated by competent workers adequately supervised. Use of vibrators to transport concrete within forms shall not be allowed.

30. Specific care shall be taken to ensure that the concrete is well worked around embedments, most notably waterstops, and that the area is free from honey combing.

31. Precautions are to be taken to protect any projecting portions of the waterstop from damage during the progress of the works and, in the case of rubber and plastic, from light and heat.

32. Great care shall be taken to prevent any foreign matter from being introduced into the concrete from the workmen's boots or any other source.

33. Laying of thin sections such as floor slabs in two courses shall not be permitted.

34. Spilled concrete shall not be reused.

35. Mixing and placing shall be carefully coordinated with finishing. Concrete shall not be placed more rapidly than it can be spread, consolidated, straight edged, and garbed or bull floated. These operations must be performed before bleeding water has an opportunity to collect on the surface.

36. To obtain good surfaces and avoid cold joints, the size of finishing crews shall be planned with due regard for the effects of concrete temperature and atmospheric conditions on the rate of hardening of the concrete.

37. Joints in slabs on grade shall be located and constructed as indicated in the drawings.

38. When saw-cut joints are required or permitted, cutting shall be timed properly with the set of concrete. Cutting shall be started when the concrete has hardened sufficiently to prevent aggregates being dislodged by the saw (within 12 hours of casting). Cutting shall be completed before shrinkage stresses become sufficient to produce cracking. The depth of the saw cut shall be between 1/4 and 1/3 of slab thickness as indicated on the drawings.

39. Slabs and paving shall be laid in an approved sequential fashion. Concrete shall not be placed in adjacent paving until 3 days from pouring have elapsed.

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40. Concrete in slabs shall be thoroughly consolidated. Internal vibration shall be used in beams and girders of framed slabs, and along the bulkheads of slabs on grade. Consolidation of slabs shall be obtained with vibrating screeds, roller pipe screeds, internal vibrators, or other acceptable means.

41. Mass concrete pours shall follow ACI 207.1R, Guide to Mass Concrete. Mass concrete shall be defined as any concrete element with a least dimension of one meter and a volume to exposed surface area ratio greater than 2.5

20. FINISHING

All coating adhesion shall conform to ASTM D4541

20.1 Unformed surfaces

20.1.1 Unless otherwise specified in the contract documents, the following finishes shall be used as applicable:

20.1.1.1 Scratched Finish

For surfaces intended to receive bonded applied cementitious applications.

20.1.1.2 Floated Finish

For surfaces intended to receive roofing, waterproofing membranes, or sand bed terrazzo.

20.1.1.3 Troweled Finish

For floor intended as walking surfaces or for reception of floor coverings.

20.1.1.4 Broom or Belt Finish

For sidewalks, garage floors, ramps, roads, and area paving.

20.1.1.5 Nonslip Finish

For exterior platforms, steps, and landings; and for exterior and interior pedestrian ramps.

20.1.2 The specified finishes for unformed surfaces shall confirm to the following:

20.1.2.1 Scratched Finish

After the concrete has been placed, consolidated, struck off, and leveled to a Class C tolerance, the surface shall be roughened with stiff brushes or rakes before the final set.

20.1.2.2 Floating Finish

After the concrete has been placed, consolidated, struck off, and leveled, the concrete shall not be worked further until ready for floating. Floating with a hand float or with a bladed power trowel equipped with float shoes, or with a powered disc float shall begin when the water sheen has disappeared and when the surface has stiffened sufficiently to permit the operation. During or after the first floating, planeness of surface shall be checked with a 3000 mm straight-edge applied at not less than two different angles. All high spots shall be cut down and all low spots filled during this procedure to produce a surface within Class B tolerance throughout. The slab shall then be refloated immediately to a uniform sandy texture.

20.1.2.3 Troweled Finish

The surface shall first be float-finished as specified in Section 20.1.2.2. It shall next be power troweled, and finally hand troweled. The first troweling after power floating shall produce a smooth surface that is somewhat free of defects but which may still show some trowel marks. Additional trowelings shall be done by hand after the surface has hardened sufficiently. The final troweling shall be done when a ringing sound is produced as the trowel is moved over the surface. The surface shall be thoroughly consolidated by the hand troweling operations. The finished surface shall be essentially free of trowel marks, uniform in texture and appearance and shall be plane to a Class A tolerance, except tolerance for concrete on metal deck shall be Class B.

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On surfaces intended to support floor coverings, any defects of sufficient magnitude to show through the floor covering shall be removed by grinding.

20.1.2.4 Broom or Belt Finish

Immediately after the concrete has received a float finish as specified in Section 20.1.2.2, it shall be given a coarse transverse scored texture by drawing a broom or burlap belt across the surface.

20.1.2.5 "Dry Shake" Finish

If a "dry shake" application of a selected metallic or mineral aggregate is called for on the contract documents, the aggregate, selected or acceptable to the DESIGNER, shall be blended with portland cement in the proportions recommended by the manufacturer of the aggregate. The surface shall be given a float finish in accordance with Section 20.1.2.2.

Approximately two-thirds of the blended material for required coverage shall be applied to the surface by a method that insures even coverage without segregation. Floating shall begin immediately after application of the first "dry shake". After this material has been embedded by floating, the remainder of the blended material shall be applied to the surface at right angles to the previous application.

The second application shall be heavier in any areas not sufficiently covered by the first application. A second floating shall follow immediately. After the selected material has been embedded by the two floatings, the operation shall be completed with a broomed, floated, or troweled finish, as designated in the contract documents. Concrete to receive the dry shake shall be non air entrained.

20.1.2.6 Nonslip Finish

Where the contract documents required a nonslip finish, the surface shall be given a "dry shake" application, as specified above, of crushed ceramically bonded aluminum oxide or other specified selected abrasive particles. The rate of application of such material shall be not less than 1.25 Kg per m

2.

20.1.3 Tolerances for unformed surfaces

20.1.3.1 Finishes with class a tolerances shall be true planes within 5 mm in 3000 mm as determined by a 3000 mm straightedge place anywhere on the slab in any direction.

20.1.3.2 Finishes with class b tolerances shall be true planes within 8 mm in 3000 mm as determined by a 3000 mm straightedge placed anywhere on the slab in any direction.

20.1.3.3 Finishes with class c tolerances shall be true planes within 6 mm in 600 mm as determined by a 600 mm straightedge placed anywhere on the slab in any direction.

20.1.3.4 When indicated on the drawings, the finish tolerance for special floors where material handling equipment is used shall be 3 mm in 3000 mm as determined by a 3000 mm straightedge placed anywhere on the slab in any direction including across construction joints.

20.1.4 Related unformed surfaces

20.1.4.1 Tops of walls or buttresses, horizontal offsets, and similar unformed surfaces occurring adjacent to formed surfaces shall be struck smooth after concrete is placed and shall be floated to a texture consistent with that of formed surfaces. Final treatment on formed surfaces shall continue uniformly across the unformed surfaces.

20.1.5 Water shall not be added to the concrete surface during finishing operations.

20.2 Formed surfaces

20.2.1 Unless otherwise specified in the contract documents, the following finishes shall be used as applicable:

20.2.1.1 Rough Form Finish

For all concrete surfaces not exposed to public view and that will not receive protective coating.

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20.2.1.2 Smooth form finish with smooth rubbed finish

For all concrete surfaces exposed to public view or surfaces that will receive protective coatings.

20.2.1.3 Smooth Rubbed Finish

Smooth rubbed finish shall be produced on newly hardened concrete no later than the day following form removal. Surfaces shall be wetted and rubbed with carborundum brick or other abrasive until uniform color and texture are produced. No cement grout shall be used other than the cement paste drawn from the concrete itself by the rubbing process.

20.2.1.4 Grout Cleaned Finish

No cleaning operations shall be undertaken until all contiguous surfaces to be cleaned are completed and accessible. Cleaning as the work progresses shall not be permitted. Mix 1 part portland cement and 1 1/2 parts fine sand with sufficient water to produce a grout having the consistency of thick paint. White portland cement shall be substituted for a part of the gray portland cement in order to produce a color matching the color of the surrounding concrete, as determined by a trial patch. Wet the surface of the concrete sufficiently to prevent absorption of water from the grout and apply the grout uniformly with brushes or a spray gun. Immediately after applying the grout, scrub the surface vigorously with a cork float or stone to coat the surface and fill all air bubbles and holes. While the grout is still plastic, remove all excess grout by working the surface with a rubber float, burlap, or other means. After the surface whitens from drying (about thirty minutes at normal temperatures), rub vigorously with clean burlap. The finish shall be kept damp for at least 36 hours after final rubbing.

20.2.1.5 Cork Floated Finish

Remove forms at an early stage, within 2 to 3 days of placement where possible. Remove ties. Remove all burrs and fins. Mix one part portland cement and one part fine sand with sufficient water to produce a stiff mortar. Dampen wall surface. Apply mortar with firm rubber float or with trowel, filling all surface voids. Compress mortar into voids using a slow-speed grinder or stone. If the mortar surface dries too rapidly to permit proper compaction and finishing, apply a small amount of water with a fog sprayer. Produce the final texture with a cork float using a swirling motion.

20.2.2 The specified finishes for formed surfaces shall confirm to the following:

20.2.2.1 Rough Form Finish

Form facing materials shall be approved for rough form finish surfaces. Tie holes and defects shall be patched. Fins exceeding 6 mm in height shall be chipped off or rubbed off. Otherwise, surfaces shall be left with the texture imparted by the forms. When membrane waterproofing is to be applied all fins and protrusions shall be removed.

20.2.2.2 Smooth Form Finish

The form facing material shall produce a smooth, hard, uniform texture on the concrete. It may be plywood, tempered concrete-form-grade hardboard, metal, plastic, paper, or other acceptable material capable of producing the desired finish. The arrangement of the facing material shall be orderly and symmetrical, with the number of seams kept to the practical minimum. It shall be supported by studs or other backing capable of preventing excessive deflection. Material with raised grain, torn surfaces, worn edges, patches, dents, or other defects that will impair the texture of the concrete surface shall not be used. Tie holes and defects shall be patched to the satisfaction of the DESIGNER. All fins shall be completely removed.

20.2.2.3 Architectural Finishes Special

Textured finish, exposed aggregate finish, and aggregate transfer finish are architectural concrete finishes and shall be produced in accordance with the requirements of the contract documents.

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21. CURING

21.1 General

Curing and protection shall be in accordance with ACI 301, ACI 305.1 and ACI 308.1 or BS standards. Water used for concrete curing shall comply in all respects with the requirements of BS EN 1008 or ACI 308R and Design General Specification for Concrete Supply, DGS 1783-001.

21.2 Curing Period

21.2.1 Good curing is vital for durable concrete. Severe measures will be taken by company if contractor does not comply. These methods include rejection of the concrete and removal of senior personnel responsible for concrete works.

21.2.2 Curing shall be maintained for at least 10 days from pouring. Curing of the concrete after the initial set shall be as per sections 21.3, 21.4 and 21.5:

Curing of precast concrete elements at precast yards (steam curing, etc) shall be specified by contractor.

21.3 Curing of top surfaces

21.3.1 Every part of the exposed surface shall be covered with a layer of sealed polyethylene per ASTM C171 or similar impermeable sheeting immediately after finishing. The sheeting shall be in close contact with the concrete, unless some initial separation is necessary to obtain a particular surface finish. The sheets shall overlap adjacent sheets at the edges by at least 400 mm, and they shall be fixed down at the ends and edges to prevent air circulation over the concrete.

21.3.2 As soon as the concrete has stiffened sufficiently and after not more than 4 hours, the layer of sheeting shall be completely replaced with a layer of wet hessian or absorptive mats covered with a layer of sealed polyethylene or similar impermeable sheeting.

21.3.3 Additional water shall frequently be introduced under the sheeting in order to keep the hessian thoroughly and permanently wet.

21.3.4 Alternatively ponding with water may be used.

21.3.5 When it is impossible to cover the whole of a surface closely with wet hessian (e.g. Where a lot of starter bars protrude from it), and if it is also impossible to pond it, as much of the surface as possible shall be cured as described above.

21.3.6 A curing membrane shall be applied to the remainder immediately after finishing operations.

21.4 Curing of vertical surfaces

21.4.1 Immediately after concrete placement, metal formwork shall be kept continuously wet until formwork is removed and normal curing can commence.

21.4.2 Directly upon removal of the formwork, the concrete shall be closely wrapped with wet hessian and enclosed with sealed polyethylene sheeting. Battening shall be used to keep both hessian and polyethylene lightly in contact with the concrete surface.

21.4.3 Additional water shall continuously be introduced on the hessian by means of trickler hoses in order to keep the hessian thoroughly and permanently wet.

21.5 Curing of inaccessible areas

21.5.1 Curing compound may be used on slab soffits, elevated beams sides and soffits, inaccessible column faces and high shear walls.

21.5.2 Curing compound shall be sprayed on the surfaces immediately upon stripping of formwork.

21.5.3 The curing compound must be compatible with any future finishes required or be totally removed.

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22. CONCRETE REPAIR

1. The finished faces of all concrete work shall be sound, solid and free from defects. All corners (except underside of foundation) shall have a 25 x 25 mm chamfer. No rendering of imperfect concrete faces will be allowed and any concrete that is defective in any way (including color) is to be cut out and replaced to such depths or be made good in such manner as the company may direct.

2. Any concrete that is damaged or unsound shall be demolished if necessary and shall be repaired and re-instated.

3. No repair work shall be undertaken before the company has inspected the defective work.

4. Repair shall not proceed until concrete has been fully cured.

5. Repair procedures and materials shall be submitted for company approval.

6. Only the highest quality materials compatible with the parent concrete shall be used for the repair.

7. Tie holes shall be filled with waterproofing materials.

8. Cracks widths in concrete which exceed the limiting values as follows, shall be subject to further review by the company.

a. Crack widths shall be limited to 0.15 mm for all buried, submerged and exposed concrete. b. Crack widths shall be limited to 0.30 mm for all concrete located in an air conditioned and

sealed internal environment. c. Crack width shall be limited to 0.10 mm for all liquid retaining structures.

23. PROTECTIVE COATING APPLICATION

Concrete, as noted on the drawings, shall be protected to prevent chlorides and other detrimental chemicals entering from the soil, ground water or atmosphere, by application of membrane or coating. Top surfaces of general paving will not require protective coatings.

24. ACCEPTANCE

Completed concrete work that fails to meet the requirements of this specification may be accepted or rejected by the company. Concrete that is rejected by company shall be removed and replaced or made acceptable in accordance with the instructions of the company.

25. PROTECTION OF PROPERTY AND PERSONNEL

1. The contractor shall protect all active utility lines including temporary lines, existing lines, systems and services already installed in the course of the project and any other lines encountered during excavation. If any of these are damaged, the company will have them repaired or replaced at the contractors cost. If existing utilities are found to interfere with his work, the contractor shall notify the company and secure written instructions for further action.

2. The contractor shall barricade open holes and depressions occurring as part of this work, and post warning lights on property adjacent to or with public access. He shall operate warning lights during hours from dusk to dawn each day and as otherwise required for safety.

3. The contractor shall protect structures, utilities, pavements and other facilities from damage caused by settlement, lateral movement, washout and other hazards created by his operations.

4. The contractor shall plan and execute all aspects of the concrete work such that the safety of personnel, the work and adjacent property is guaranteed and such that a minimum of inconvenience is caused.

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26. CLEAN UP

Upon completion, leave project site clear of debris and surplus material resulting from work of this contract. All debris and surplus materials shall be disposed of, off plant limits in a manner meeting all local authority requirements.

27. CATHODIC PROTECTION FOR STEEL IN CONCRETE

Refer to Specification DGS-1674-001 - Design, Installation, Commissioning and Monitoring of Cathodic Protection for Plant Facilities, section 14.10.2 - Steel in Concrete, for the design philosophy and description of the construction details of the cathodic protection for the reinforcement.