SPECIFICATION 1132 MASS CONCRETE SUBBASE

Hornsby Shire Council

ABN 20 706 996 972 PO Box 37, Hornsby NSW 1630 Phone 02 9847 6666 Email [email protected]

296 Peats Ferry Rd, Hornsby 2077 Fax 02 9847 6999 Web hornsby.nsw.gov.au

SPECIFICATION 1132

MASS CONCRETE SUBBASE

© AUS-SPEC (Oct 11) July 2016

1132 Mass Concrete Subbase

© AUS-SPEC (Oct 11) HORNSBY SHIRE COUNCIL

SPECIFICATION 1132 – MASS CONCRETE SUBBASE

CLAUSE CONTENTS PAGE

GENERAL ............................................................................................................................................................ 1

1.1 RESPONSIBILITIES ............................................................................................................................. 1

1.2 CROSS REFERENCES ........................................................................................................................ 1

1.3 REFERENCED DOCUMENTS ............................................................................................................. 1

1.4 STANDARD ........................................................................................................................................... 2

1.5 INTERPRETATIONS ............................................................................................................................ 2

1.6 SUBMISSIONS ..................................................................................................................................... 2

1.7 INSPECTION ........................................................................................................................................ 3

PRE-CONSTRUCTION PLANNING .................................................................................................................... 6

2.1 ACTIVITY PLAN .................................................................................................................................... 6

2.2 DESIGN AND CONTROL OF BASE AND SUBBASE MATERIAL ....................................................... 6

MATERIALS ......................................................................................................................................................... 7

3.1 CEMENT ............................................................................................................................................... 7

3.2 FLY ASH ............................................................................................................................................... 7

3.3 WATER ................................................................................................................................................. 7

3.4 ADMIXTURES ....................................................................................................................................... 7

3.5 AGGREGATES ..................................................................................................................................... 8

3.6 STEEL REINFORCEMENT ................................................................................................................ 10

3.7 CURING AND DEBONDING COMPOUNDS ..................................................................................... 10

3.8 CONCRETE FOR SUBGRADE BEAMS ............................................................................................ 11

3.9 BINDER CONTENT FOR MASS CONCRETE ................................................................................... 11

EXECUTION ....................................................................................................................................................... 11

4.1 PROVISION OF TRAFFIC .................................................................................................................. 11

4.2 ESTABLISHMENT .............................................................................................................................. 12

1132 Mass Concrete Subbase

© AUS-SPEC (Oct 10) HORNSBY SHIRE COUNCIL

4.3 CONCRETE QUALITY REQUIREMENTS ......................................................................................... 12

4.4 TRIAL MASS CONCRETE SUBBASE ............................................................................................... 12

4.5 SUBGRADE BEAMS .......................................................................................................................... 13

4.6 PRODUCTION AND TRANSPORT OF CONCRETE ......................................................................... 14

4.7 PLACING AND FINISHING CONCRETE SUBBASE ......................................................................... 15

4.8 JOINTS ................................................................................................................................................ 18

4.9 CURING AND DEBONDING............................................................................................................... 19

4.10 CONCRETE CRACKING .................................................................................................................... 19

4.11 ACCEPTANCE OF CONCRETE STRENGTH AND THICKNESS ..................................................... 20

4.12 REMOVAL AND REPLACEMENT OF SUBBASE .............................................................................. 22

4.13 LIMITS AND TOLERENCES ............................................................................................................... 17

MEASUREMENT AND PAYMENT .................................................................................................................... 24

5.1 GENERAL ........................................................................................................................................... 24

1132 Mass concrete subbase

© AUS-SPEC (Oct 11) 1 HORNSBY SHIRE COUNCIL

1132 MASS CONCRETE SUBBASE

1 GENERAL

1.1 RESPONSIBILITIES

Objectives General: Provide mass concrete subbase and associated components as documented.

Performance Quality: Requirements for quality control and testing, including maximum lot sizes and minimum test frequencies to conform with 0161 Quality (Construction).

1.2 CROSS REFERENCES

General Requirement: Conform to the following:

- 0136 General requirements (Construction).

- 0161 Quality (Construction) or 0167 Integrated management.

1.3 REFERENCED DOCUMENTS

The following documents are incorporated into this worksection by reference:

Standards AS 1012 Methods of testing concrete AS 1012.1-1993 Sampling of fresh concrete AS 1012.3.1-1998 Determination of properties related to the consistency of concrete -

Slump test AS 1012.3.3-1998 Determination of properties related to the consistency of concrete - Vebe

test AS 1012.4.2-1999 Determination of air content of freshly mixed concrete - Measuring

reduction in air pressure in chamber above concrete AS 1012.8.1-2000 Method for making and curing concrete - Compression and indirect

tensile test specimens AS 1012.9-1999 Determination of the compressive strength of concrete specimens AS 1012.13-1992 Determination of the drying shrinkage of concrete for samples prepared

in the field or in the laboratory AS 1012.14-1991 Method for securing and testing cores from hardened concrete for

compressive strength AS 1141 Methods for sampling and testing aggregates AS 1141.6.1-2000 Particle density and water absorption of coarse aggregate - Weighing-in-

water method AS 1141.11.1-2009 Particle size distribution – sieving method AS 1141.12-1996 Materials finer than 75 µm in aggregates (by washing) AS 1141.13-2007 Material finer than 2 µm AS 1141.14-2007 Particle shape, by proportional calliper AS 1141.18-1996 Crushed particles in coarse aggregate derived from gravel AS 1141.22 -2008 Wet/dry strength variation AS 1141.24-1997 Aggregate soundness - Evaluation by exposure to sodium sulfate solution AS 1160-1996 Bituminous emulsions for the construction and maintenance of pavements AS 1289 Methods of testing soils for engineering purposes AS 1289.3.6.3-2003 Soil classification tests - Determination of the particle size distribution of a

soil - Standard method of analysis using a hydrometer AS 1289.4.2.1-1997 Determination of the sulfate content of a natural soil and the sulfate

content of the groundwater - Normal method AS 1379-2007 Specification and supply of concrete AS 1478 Chemical admixtures for concrete, mortar and grout AS 1478.1-2000 Admixtures for concrete



AS 1554.3 – 2008 Structural steel welding – Welding of reinforcing steel AS 2350 Methods of testing portland and blended cements AS 2758 Aggregates and rock for engineering purposes AS 2758.1-1998 Concrete aggregates AS 3582 Supplementary cementitious materials for use with portland and blended

cement AS 3582.1-1998 Fly ash AS 3583 Methods of test for supplementary cementitious materials for use with

portland cement AS 3583.13-1991 Determination of chloride ion content AS 3799-1998 Liquid membrane—forming curing compounds for concrete AS 3972-2010 General purpose and blended cements AS/NZS 4671: 2001 Steel reinforcing materials AS/NZS 4680:2006 Hot-dipped galvanized (zinc) coatings on fabricated ferrous articles SAA HB 155 – 2002 Guide to the use of recycled concrete and masonry materials Other publications AUSTROADS AP-C87-2010 Austroads Glossary of terms AGPT04C – 2009 Guide to Pavement Technology Part 4C: Materials for Concrete Road

Pavements AGPT04E - 2008 Guide to Pavement Technology Part 4E: Recycled Materials AGPT04G - 2009 Guide to Pavement Technology Part 4G: Geotextiles and Grids AGPT04J – 2008 Guide to Pavement Technology Part 4J: Aggregate and source rock

1.4 STANDARD

General Standard: To AS 1379.

1.5 INTERPRETATIONS

Abbreviations General: For the purposes of this worksection the following abbreviations apply:

CRCP: Continuously reinforced concrete.

JRCP: Jointed reinforced concrete.

PCP: Jointed plain concrete.

SFCP: Jointed steel fibre reinforced concrete pavement.

Definitions General: For the purposes of this worksection the following definitions apply:

- Chert: Fine grained silica-rich sedimentary rock that may contain small fossils.

- Lot: A continuous placement of up to 50 m3 of subbase concrete.

1.6 SUBMISSIONS

Acceptance criteria General: All submissions will be subject to the approval of the Superintendent.

Documents Submit the following for approval:

- Design:

. Design and control of concrete mixes to achieve approval of the nominated mix.

. Proposed changes to the nominated mix.

. Proposed methods of concrete production placing and finishing

- Drawings:

. Subbase placement plan: As part of Quality Plan to show placements and daily out-puts.

. Joint details.

- Calculations:

. Curing compound: Application rate calculated by test and certified.

. Subbase levels: As derived from design finished levels.



- Execution details:

. Subgrade work as executed survey.

. Concrete mixing procedures.

. Concrete placing and finishing.

. Trial subbase.

. Concrete curing and protection.

. Conformity with dimensions and quality.

. Variation to subbase level.

- Materials: Technical data of materials as specified for the following:

. Cement.

. Flyash.

. Admixtures.

. Water.

. Aggregates.

. Steel reinforcement.

. Sealant.

. Curing compound.

- Technical data: [complete/delete]

- Warranties: [complete/delete]

Prototype: Trial subbase for incorporation in the work.

Type tests: [complete/delete]

- Consistency test results.

- Compressive strength.

-Type test results: [complete/delete]

1.7 INSPECTION

Notice General: Give notice so that the inspection may be made of the following:

Summary of HOLD POINTS

Clause/subclause Requirement Notice for inspection Release by

PRE-CONSTRUCTION PLANNING

Design and control of concrete mixes

- Nominated mix Details of nominated concrete mix and/or changes to approved mix

28 days before ordering concrete

Superintendent

- Certificates of compliance

Submit NATA certificates of compliance

28 days before ordering concrete

Superintendent

EXECUTION

Establishment

- Subgrade survey Work as executed survey of the subgrade to the full extent of the works.

2 working days prior to commencing any works

Superintendent

- Subgrade survey Non conforming levels local redesign for approval

2 working days prior to commencing any works

Superintendent

Trial mass concrete subbase

- Trial section Construct a trial section to demonstrate capability to proceed

At least 5 working days of proceeding with the remaining works

Superintendent



Clause/subclause Requirement Notice for inspection Release by

- Procedure after placement

Non conforming trials will be rejected

At least 5 working days of proceeding with the remaining works

Superintendent

Subgrade beams - Excavation

Submit excavation compacted to approved condition

2 working days before concrete

Superintendent

Production and transport of concrete -Handling, storing and batching

Proposed methods for handling, storage, batching materials

At least 4 weeks prior to planned commencement of work

Superintendent

Placing and finishing concrete subbase - Equipment and methods

Submit full details of placing and finishing concrete together with a paving plan

At least 4 weeks prior to planned commencement of work

Superintendent

Acceptance of concrete strength and thickness – Conformance for thickness

Assess subgrade and subbase survey

Within 2 working days of completing concrete works

Superintendent

Removal and replacement of subbase - General

Method of removal to preserve adjoining subbase

7 days before commencement of removal

Superintendent

Summary of WITNESS POINTS – Off-site activities

Clause/subclause Requirement Notice for inspection

PRE-CONSTRUCTION PLANNING

Design and control of concrete mixes – Compressive strength

Submit compressive strength gain curve

With nominated mix data

MATERIALS

Cement - Nominated cement Nominate brand, quality and source

With nominated mix data and as directed

Flyash - Nominated flyash Nominate powerhouse source With nominated mix data and as directed

Admixtures - Nominated admixture

Nominate proprietary source, concentration, type and name. NATA Certificate of Compliance

With nominated mix data and as directed

Aggregates - Nominated aggregates

Nominate sources and geological type. NATA Test Report on quality and grading


Steel reinforcement- General Supply certificates with results of mechanical tests and chemical analysis

Prior to delivery on site

Curing and surface debonding compounds - General

Certificate of Compliance including the efficiency rate


Summary of WITNESS POINTS – On-site activities


MATERIALS

Aggregates - Storage Storage and handling to preserve quality of aggregate

Progressive

EXECUTION

Subgrade beams - Provision Provide below the subbase at joints in the concrete base

7 days




Trial mass concrete subbase – Trial section

Notify the Superintendent for demonstration of trial mass concrete subbase

5 working days prior to demonstrating the works

Production and transport of concrete - Agitation

Submit times of addition of cement to the aggregate and the means of verification

7 days

Placing and finishing concrete subbase

- Equipment and methods Give 7 days notice for intended commencement of construction

7 days

- Consistency Submit consistency test results Progressive

- Evaporation and moisture loss

Ground surface damp, clean and compacted

Progressive

- Evaporation and moisture loss

Precautionary measures to prevent moisture loss when evaporation rate exceeds prescribed limits

Progressive

- Paving in general Provide base slab anchors if required

Progressive

- Paving in general Construction joint if hand or mechanical paving is disrupted

Progressive

- Alignment and surface tolerances

Remediation of surfaces above or below level tolerances

Progressive

- Protection of work Maintain concrete temperature above 5°C for 24 hours

Progressive

- Curing and debonding - Curing

Check application rate with a nominated lot.

Progressive

Joints – Transverse and longitudinal construction joints

Location and condition Progressive

Concrete cracking - Rejected concrete

Treatment as directed by Superintendent

Progressive

Spall treatment and bond breaker – Treatment of spalling

Treatment as directed by Superintendent

Progressive

Acceptance of concrete strength and thickness

- Cylinder strength testing (in the trial mix)

Modify mix and/or production methods of non conforming concrete

Progressive

- Concrete cylinders Supply moulds and arrange sampling, curing, delivery and testing of specimens

Progressive

- Testing by specimens cut from the work

Cut cores in the presence of the Superintendent

Progressive


Delay retesting of non conforming samples for at least 72 hours

Progressive


Advise proposed method of restoration for approval

Progressive




- Conformance for thickness Submit measurements of subbase thickness and reject areas of insufficient thickness

As directed

- Conformance for thickness Reject insufficiently thick concrete

As directed

Removal and replacement of subbase - Removal and replacement

Damaged pavement adjacent rejected subbase

As directed

2 PRE-CONSTRUCTION PLANNING

2.1 ACTIVITY PLAN

General Program: Plan the following activities:

- Provide planning resources to allocate plant and personnel for the contract period.

- Program the work to meet the constraints of HOLD POINTS and WITNESS POINTS.

2.2 DESIGN AND CONTROL OF CONCRETE MIXES

Nominated mixes Approval: Submit details of concrete mix(es) and the constituent materials including source, moisture condition of the aggregates (oven dry, surface saturated dry or other specified moisture content), setting time, soundness, compressive strength, shrinkage, fineness and nominated compatibility index (in range 60 -90). This is a HOLD POINT.

On approval: Each such mix will be known as a ‘nominated mix’.

Certificates of compliance Submission: Submit NATA Certificates of compliance for each constituent and nominated mix.

Verification: Provide certificates from a NATA registered laboratory. All phases of any particular test must be performed at one laboratory. All relevant test results to accompany the certificate and be within twelve months of the submission date. This is a HOLD POINT.

Compressive strength Submission: Submit the compressive strength gain curve showing the compressive strengths at ages 3, 7, 10 and 28 days determined to AS 1012.9. Carry out NATA testing at 3, 7, 10 and 28 days for three specimens of concrete produced from a batch of the nominated mix. Take the compressive strength as the average of individual results within 1.0 MPa of the median. This is a WITNESS POINT.

Approved mix(es) Identical mix: To avoid testing the nominated mix, submit results from earlier testing of a mix identical with the nominated mix for approval.

Prior approval: A mix may be approved due to ‘prior approval’ under the following conditions:

- If the mix was used in a separate contract within 12 months of the proposed works date.

- If fully approved details have been previously used.

- If the constituent materials and quality remain unchanged from those previously approved.

- If the in-service performance of the concrete incorporating the nominated mix is acceptable.

Variations to approved nominated mixes and materials Approval required: Any change to the approved mix, its method of production or source of supply of constituents requires approval prior to proposed implementation.

Non-conformance: Consider any change made without prior approval to a material in the approved mix as a non-conforming material. Concrete containing this material may become Rejected Concrete.

Costs: Borne by the Contractor.

Approval without trials: If the variations to the quantities of the approved mix are less than 10 kg for cement and flyash per m3 of concrete and 5% by mass for each other constituent, except admixtures.



3 MATERIALS

3.1 CEMENT

General Standard: GP cement to AS 3972 and tested to AS 2350 (various).

Nominated cement Brand and source: Nominate the brand and source of the cement when submitting details of the nominated mix in accordance with Nominated mixes. Use only the nominated cement in the work. This is a WITNESS POINT.

Proof of quality: Provide documentary evidence of the quality and source of the cement upon request at any stage of the work.

Storage time: Prior to use, re-test cement that has been stored for a period in excess of three months from the time of manufacture to ensure the cement still complies with AS 3972.


Transport: Cement in watertight packaging and protect from moisture until used. Do not use caked or lumpy cement.

3.2 FLYASH

General Standard: Fly ash to AS 3582.1.

Nominated fly ash Powerhouse source: Nominate the powerhouse source of the fly ash in accordance with Nominated mixes. On approval of a nominated mix, use only the fly ash from the nominated powerhouse. This is a WITNESS POINT.

Proof of quality: Provide documentary evidence of the quality and source of the fly ash upon request at any stage of the work.

3.3 WATER

General

Standard: Chloride ion to AS 3583.13 and sulphate ion to AS 1289.4.2.1.

Limits for impurities in mixing water: To AS 1379.

Quality: Use water in the production of concrete that is potable, free from materials harmful to concrete or reinforcement, and neither salty nor brackish.

Limits: Provide water with less than:

- 300 parts per million of chloride ion, determined by AS 3583.13.

- 400 parts per million of sulphate ion, determined by AS 1289.4.2.1.

3.4 ADMIXTURES

General Standard: Chemical admixtures to AS 1478.1.

Quality: Provide admixtures free from calcium chloride, calcium formate, or triethanolamine or any other accelerator. Do not use admixtures or combinations of admixtures without prior written approval.

Dosage: Vary the dosage of chemical admixture to account for air temperature and setting time in accordance with the manufacturer’s recommendations.

Compatibility: Certificate from the manufacturer required for combinations of two or more admixtures to ensure compatibility.

Nominated admixture

Source and type: Nominate the proprietary source, type, dose rate, name and method of incorporation of each admixture to be used in accordance with nominated mixes. Submit NATA certificates of compliance and the proposed dosage chart. On approval of a nominated mix, use only the admixture and dosage that is approved.



Variation to mixture: If the Contractor proposes to vary the admixture between warm and cool seasons such variation is to constitute a proposed change to an approved mix for the purposes of Variations to approved mixes. This is a WITNESS POINT.

Proof of quality: Provide documentary evidence of the quality upon request at any stage of the work.

Types of admixtures Air entraining agent: An air-entraining agent to Air content (Concrete quality requirements) may be included.

Excess air content: Reject fresh concrete with an air content not conforming to Air content(Concrete quality requirements).

Warm season retarder: To control slump within the limits stated in Consistency during the warm season, (October to March inclusive), use a lignin or lignin-based (‘ligpol’) set-retarding admixture (Type Re or Type WRRe) as approved.

Cool season retarder: During the cool season, (April to September inclusive), use only a lignin or lignin based set-retarding admixture containing not more than 6 % reducing sugars (Type WRRe complying with AS 1478.1).

Alkali contribution: For mixes with less than 50 kg/m3 fly ash, the total alkali contribution (measured as Na2 O) from all admixtures used in any mix must not exceed 0.20 kg/m3.

Types: Superplasticisers and high range water reducers (type HR, WR, Re) may be used.

3.5 AGGREGATES

General Standards: AS 2758.1 and Austroads AGPT04J.

Quality: Supply at least 40% by mass of the total aggregates in the concrete mix of quartz sand aggregate having a nominal size of < 5 mm and containing at least 70 % quartz, by mass.

Durability: All constituent, fraction of constituent or aggregates to conform to AS 1141.22 and the following:

- Wet Strength not less than 50 kN.

- 10% Fines Wet/Dry Variation not to exceed 35%.

Chert fragments: Consider chert fragments as ‘quartz’ for the purpose of this worksection, provided that the chert content does not exceed quartz content.

Type: Clean, durable materials sourced from natural gravel, crushed stone, air-cooled iron blast furnace slag and sand. Steel-plant slag is not acceptable.

Samples: During the contract, all aggregate testing must be on samples taken either from dedicated stockpiles or from materials delivered to site.

Soluble salt content: Within 12 months prior to the date of closing of tenders, all aggregate must be assessed for soluble salt content.

Chloride and sulphate ion contents: Aggregates may only be used if the chloride and sulphate contents indicated for the concrete are not greater than 0.8 kg/m3 and 5% respectively.

Recycled concrete aggregate (RCA): The use of course aggregates from demolition concrete or RCA to conform with SAA HB 155 and Austroads AGPT04E.

Blending: If blending coarse RCA with natural aggregates ensure substitution rates are below 30 %.

Nominated aggregates Source and type: Nominate the sources of aggregate proposed and submit details of the geological type of each aggregate.

Proposed grading: Provide NATA Certified Laboratory Test Reports on the quality and grading of the aggregate proposed. Identify the grading as the ‘Proposed Grading’.

Blending of aggregates: Submit test reports for each constituent material showing the proportions in which the various sizes are combined. The aggregate from each source and the combined aggregate to conform with the requirements of this Clause. This is a WITNESS POINT.

Fine aggregate Standard: Provide fine aggregate with a nominal size of less than 5mm and conform with AS 2758.1 in respect of bulk density, water absorption (maximum 5 %), material finer than 2 µm, impurities and reactive materials. Alkali-reactivity testing is not required.

Quality: Provide fine aggregate consisting of clean, hard, tough, durable, uniform, uncoated grains.



Manufacture fine aggregate: Any manufactured fine aggregate fraction must be crushed coarse aggregate complying with Coarse aggregate cohesionless when tested to AS 1289.3.6.3.

Properties: Fine aggregate to conform to the Fine aggregate properties table.

Fine aggregate properties table

Property Requirement Test method

Bulk Density 1200 kg/m3 minimum AS 1141.4(1)

Water Absorption 5.0% maximum, except slag aggregate: 6.0%

AS 1141.5 and AS 1141.6.1

Material finer than 75 µm Maximum 10.0 % AS 1141.12

Material finer than 2 µm Maximum 1.0 % AS 1141.13

Soundness 12 % max weighted average loss AS 1141.24

Organic impurities Maximum 0.5 % AS 1289.4.1.1

Sugar content Less than 1 part in 10,000 AS 1141.35

Notes: (1) ‘Bulk density’ in AS 2758.1 means the same as ‘unit mass’ in AS 1141.4.

Soundness: Do not exceed the limits shown in the Sodium sulphate soundness limits table for the sodium sulphate soundness determined by AS 1141.24.

Sodium sulphate soundness limits table

Australian Standard Sieve % Loss by mass

4.75 mm to 2.36 mm 2.36 mm to 1.18 mm 1.18 mm to 600 m 600 m to 300 m

4 6 8 12

Blending: In the case of a blend of two or more fine aggregates, the above limits apply to each constituent material.

Grading: Provide fine aggregate and grading determined by AS 1141.11.1 within the limits shown in the Fine aggregate grading table.

Fine aggregate grading table

Australian Standard sieve Proportion passing(% of mass of sample)

Deviation from proposed grading (% of mass of sample)

9.50 mm 4.75 mm 2.36 mm 1.18 mm 600 m 300 m 150 m 75 m

100 90–100 65–95 40–80 24–52 8–25 1–8 0–3

± 3 ± 10 ± 10 ± 10 ± 5 ± 2

Coarse aggregate Standard: To AS 2758.1 in respect of particle density, bulk density, water absorption (maximum 2.5 %), material finer than 75 µm, weak particles, light particles, impurities and reactive materials, iron unsoundness and falling or dusting unsoundness. Alkali-reactivity testing is not required.

Quality: Provide coarse aggregate consisting of clean, crushed, hard durable rock, metallurgical furnace slag or gravel. If required, wash coarse aggregates to satisfy these requirements.

Properties: Coarse aggregate to conform to the Coarse aggregate properties table.

Coarse aggregate properties table

Property Specification limits Method

Bulk Density 1200 kg/m3 minimum AS 1141.4(1)

Water absorption Slag: 6 % max

Other: 5 % max

AS 1141.6.1



Material finer than 75 m Maximum 2.0 % AS 1141.12

Material finer than 2 m Maximum 1.0 % AS 1141.13

Particle shape, 2:1 and 3:1 ratios Maximum 35 % and 10 % AS 1141.14

Wet strength Minimum 50 kN AS 1141.22

Wet/dry strength variation Maximum 35 % AS 1141.22

Soundness - loss in mass Maximum 9.0% AS 1141.24

Fractured faces (two or more) Minimum 80% AS 1141.18

Notes: (1) ‘Bulk density’ in AS 2758.1 means the same as ‘unit mass’ in AS 1141.4.

Grading: Provide course aggregate with grading determined by AS 1141.11.1 within the limits given in the Coarse aggregate grading table.

Coarse aggregate grading table

Australian Standard sieve Proportion passing(% of mass of sample)

Deviation from proposed grading (% of mass of sample)

26.50 mm 19.00 mm 13.20 mm 9.50 mm 4.75 mm 2.36 mm

100 95–100 (accepted design mix) 25–55 0–10 0–2

± 2 ± 5 ± 5 ± 3

Storage Storage areas: Provide a concrete floor to all storage areas and prevent the aggregates becoming intermixed or mixed with foreign materials or segregated.

Exclusion of foreign matter: Locate the storage area and mixing plant to ensure delivery vehicles, loaders and trucks cannot introduce foreign matter to the aggregates at any time.

Cease production: Immediately cease production of concrete upon the introduction of foreign matter or if the superintendent requests due to possible contamination. On approval that the condition has been rectified, resume production of concrete and delivery of materials. This is a WITNESS POINT.

3.6 STEEL REINFORCEMENT

General Standard: Steel reinforcement to AS/NZS 4671.

Type and size: As shown on the drawings.

Cleanliness: Free from loose or thick rust, grease, tar, paint, oil, mud, millscale, mortar or any other coating, but not brought to a smooth polished condition.

Proof of quality: Supply test certificates for the steel reinforcement showing results of mechanical tests and chemical analysis. This is a WITNESS POINT.

Sample testing: If there is not a test certificate available, sample and test to verify that all properties conform to AS/NZS 4671.


Bar chairs: Plastic bar chairs or plastic tipped wire chairs capable of withstanding a load of 200 kg mass on the chair for one hour at 23 ± 5°C without malfunction. Demonstrate that the proposed chairs conform to these requirements.

3.7 CURING AND SURFACE DEBONDING COMPOUNDS

General Standards: AS 3799, AS 1160 and AGPT04C clause 6.

Efficiency index: Submit a current Certificate of compliance for the curing compound from a NATA Laboratory. Details to include the non-volatile content and confirmation of an Efficiency Index not less than 90% when tested to conform with AS 3799, Appendix B . This is a WITNESS POINT.



Alternative curing compounds and debonding

Type Suitability with bituminous/asphaltic surfacing

Base type

Wearing surface No wearing surface

C5 hydrocarbon resin compound complying with AS 3799 Class B and with no aromatic hydrocarbon additions. *

Yes Yes JRCP

Water borne hydrocarbon resin or styrene butadiene resin (SBR) complying with AS 3799 Class Z. *

Yes JRCP

Bitumen emulsion grade CRS/170 complying with AS 1160. *

Yes Yes

White pigmented wax emulsion Class A Type 2. *

Yes PCP, JRCP, CRCP, SFCP

Debonding bitumen sprayed seal with 5-7 mm aggregate

Yes Yes PCP, JRCP, CRCP

Notes: * For paving in NSW from November to March, a Type 2 compound must be used which contains a titanium dioxide reflective pigment. At all other times, a Type 1-D compound must be used. Different states may have different requirements for the alternative use of curing compounds. Refer to the specific State Road Authority for more information.

3.8 CONCRETE FOR SUBGRADE BEAMS

General Strength: 32 MPa normal class to conform with AS 1379.

Aggregate size: Maximum nominal size 20 mm.

Slump at the point of placement: 50 – 80 mm.

3.9 BINDER CONTENT FOR MASS CONCRETE

General Binder content: The hydraulic, cementitious binder content to conform to the following table:

Mix Category Flyash (kg/m3)(1) Cement (kg/m3)(1) Total binder (kg/m3)(1)

Subbase 100 minimum 90 minimum 250 minimum (1) per yielded cubic metre of concrete

Variation approval: Vary the constituents to suit local experience, availability and recommendations of local and state authorities.

4 EXECUTION

4.1 PROVISION FOR TRAFFIC

General Control of traffic: Conform to the following:

- Conform with worksection 1101 Control of traffic.

- Conform with Traffic Guidance Scheme in 1101 Control of traffic.



4.2 ESTABLISHMENT

Subgrade survey Measure the subbase invert levels: If the underlying layer is required to be spray sealed, take levels on the top of the seal and after removal of foreign or loose material such as aggregate.

Method: Report levels to the nearest mm and survey on 5.0 m grid on a plan area.

Requirement: Submit work as executed survey of the subgrade to the full extent of the works. Highlight any locations where the actual level is higher then the design levels. This is a HOLD POINT.

Nonconforming levels: In the case of high nonconforming levels locally redesign the pavement levels as directed by the Superintendent. This is a HOLD POINT.

4.3 CONCRETE QUALITY REQUIREMENTS

Compressive strength Testing to conform with: AS 1012.9.

Minimum compressive strength at 7 days: 4 MPa.

Minimum compressive strength at 28 days: 6 MPa.

Maximum compressive strength at 28 days: 15 MPa.

Exception: If the nominated mix has a 28 day shrinkage less than 400 µε then a maximum strength less than 20 MPa is acceptable.

Drying shrinkage Shrinkage: The drying shrinkage of the nominated mix determined by AS 1012.13 to conform to:

- For maximum aggregate size > 20 mm, maximum 450 µε after 21 days air drying.

- For maximum aggregate size ≤ 20 mm, maximum 500 µε after 21 days air drying.

Consistency Consistency: Measure the slump to conform with AS 1012.3.1.

Acceptable ranges: The measure slump must be with the following acceptable ranges:

- For mechanically placed concrete: 25 mm - 40 mm.

- For hand placed concrete: 50 mm - 65 mm.

Special circumstances: Prior approval required to use concrete with an unacceptable slump range such as light aggregates and blast furnace slag aggregates.

Slipform concrete mixes: Assess the Vebe reading during trial mixing to conform with AS 1012.3.3.

Air content Air content: If an air entraining agent is used, limit the air content of the fresh concrete as discharged from the transport vehicle ready for placement to 5.0 ± 2.0% tested to AS 1012.4.2.

4.4 TRIAL MASS CONCRETE SUBBASE

Trial section Submit notice: Notify the Superintendent for inspection of demonstration of the works involving the trial mass concrete subbase. This is a WITNESS POINT.

Requirement: Prior to the commencement of paving, submit a trial section of mass concrete subbase including curing and jointing to demonstrate capability of constructing subbase to conform with this worksection. This is a HOLD POINT.

Trial section: Construct as follows:

- So that it may be incorporated in to the finished work.

- For mechanical paving between 50 and 100 m length, or lesser length as approved. Separate trials required for each paver.

- For manual paving between 15 and 50 m length, or lesser length as approved.

- Width as proposed for the work.

Materials and methods: Construct the trial mass concrete subbase using the materials, concrete mix, equipment and methods for the entire subbase works.

Procedure after placement Approved trial section: Continue the remaining works following the approval of the trial section.



Deficient trial section: If there are deficiencies in the trial concrete subbase the trial section may not be approved. Review the method, equipment, materials and personnel and submit a report. A further length of trial concrete subbase may be requested.

Procedure review: If after 3 trials the subbase is still deficient then a revised procedure will be required.

New trial section: If changes by the Contractor in the equipment, materials, mix, plant or rate of paving are made or for any other reason a new trial section may be requested.

Non compliance: Trial concrete subbase that does not comply with the worksection will be rejected, removed and reinstated conforming with Action on rejection and Rejected concrete. This is a HOLD POINT.

Remedial works: Immediately make good any damage caused by such removal to the subgrade or subgrade beams and notify the Superintendent.


4.5 SUBGRADE BEAMS

Provision Location: Provide below the subbase at expansion joints and isolation joints in the concrete base as shown in the Drawings or as directed. Construct subgrade beams before the subbase. This is a WITNESS POINT.

Extent: Full length of joints unless otherwise indicated on the Drawings.

Excavation Dimensions and levels: Excavate to the dimensions shown on the Drawings. Finish the top surface of the subgrade beam level with the top of the subgrade.

Method: Remove all loose material and trim the vertical faces to neat lines. Re-compact the bottom of the trench as required, to the degree of consolidation of the adjacent undisturbed material. This is a HOLD POINT.

Disposal of excavated material: Legally by the Contractor.

Concrete Properties: To 0319 Minor concrete works.

Minimum compressive strength: At 28 days must be 32 MPa.

Steel reinforcement Conform to: Reinforcement must align to the following:

- Formed to the dimensions and shapes shown on the drawings.

- Bent to an internal bend radius at least twice the diameter of the bar.

- Do not bend or straighten in a manner that will damage the material.

- Do not use with kinks or bends not shown on the drawings.

- Do not heat for the purpose of bending.

Bar splicing: Fabricate all reinforcement in the lengths indicated on the Drawings. Splice to conform with the drawings. Obtain approval for any additional splicing by location and method.

Plan lengths: Conform to the following for length of lapped splices for unhooked bars not shown on the Drawings will be as follows:

- Plain bars, Grade 250: 40 bar diameters

- Deformed bars, Grade 500: 40 bar diameters

- Hard-drawn wire: 50 bar diameters

- Reinforcement fabric: Overlap between the outermost wire in each sheet of fabric transverse to the direction of the splice greater than the pitch of the transverse wires plus 25 mm.

Secure ends: The ends of the bars forming a lapped splice must be welded or securely wired together in at least 2 places. Welding to comply with AS 1554.3.

Construction and protection Fill voids: If any loose material is removed, fill the voids with mortar or concrete and screed to provide a surface flush with the top of the subgrade beam.

Finish: Use a steel float to produce a smooth surface finish, free of any texture.

Protection: Protect from damage by plant, motor vehicles and the paving operation.



Damage: Make good any damage.


Curing Timing: Cure the top surface of the subgrade beam in accordance with Placing and finishing concrete subbase (curing) before placing the subbase.

Bond breaker Treatment of subgrade beams: Treat the top surface of the subgrade beam with a bond breaker consisting of a further application of curing compound neither less than 24 hours nor more than 72 hours before placing of subbase concrete.

4.6 PRODUCTION AND TRANSPORT OF CONCRETE

General Standard: To AS 1379 for mixers and agitation methods.

Handling, storing and batching Submit: Proposed details for the following methods:

- Handling, storing and batching materials for concrete.

- Monitoring and measuring the constituent materials for concrete.

- Mixers and methods of mixing.

- Method of transport.

This is a HOLD POINT.

Verify scales accuracy: Submit certificates of calibration issued by a NATA registered laboratory as evidence of the accuracy of the scales prior to handling and batching of material.

Measurement: Weigh cementitious material in an individual hopper, with the cement weighed first.

Moisture content: Determine the moisture content of the aggregates at least daily immediately prior to batching. Make corresponding corrections to the quantities of aggregates and water.

Continuous weighing: If a continuous type mixer is used, measure the components by a method of continuous weighing as approved, except for liquids which may be measured by volume or flow rate meter.

Storage: Store materials only on sites specifically designated for the purpose. Do not use a new storage site without prior approval.

Mixing time Stationary batch mixers: The minimum mixing time must not be less than 54 seconds plus 6 seconds for each cubic metre.

Mobile batch mixers: The minimum mixing time must be the full period of mixing provided at either the testing station or the point of placement. All other mixing or agitation must be ignored for the purpose of assessing the actual mixing time for a specific batch.

Maximum mixing time: 5 minutes for split drum mixers or 10 minutes otherwise.

Admixture addition Pre-dilute: Admixtures must be separately and thoroughly pre-diluted in the mixing water prior to their introduction to other materials.

Manufacturer’s instructions: Mixing to conform with the manufacturer’s instructions and ensure no adverse interaction occurs.

Batch delivery docket Identification number: The docket / Certificate must be pre-numbered and accompany each batch or load of concrete.

Record details: Including the time for completion of batching depending on the type of mixing. This will include time for charging and/or mixer discharge and/or slump adjustment.

Addition of water: The delivery docket must clearly indicate the amount of water added, but in no circumstance is the water/cement ratio to be exceeded.

Agitation Addition of water: For truck-mixed concrete, add water in accordance with AS 1379 within ten minutes of completion of batching and within 200 m of the batching facilities.



Cement addition: After addition of the cement to the aggregate, concrete to be incorporated into the work within:

- 90 minutes, where transported by truck mixer or agitator.

- 60 minutes, where transported by non-agitating trucks.

Outside of the time limitations: Legally dispose of any material delivered in excess of these time limitations with the cost borne by the Contractor.

Verify time added: Submit times of addition of cement to the aggregate and the means of verification. This is a WITNESS POINT.

Maximum size of batch: The size of the batch in an agitator vehicle not to exceed the manufacturer’s rated capacity nor exceed 80 % of the gross volume of the drum of the mixer.

Maximum holding: If delays necessitate holding a batch in the mixer then mixing may continue for 10 minutes maximum or 5 minutes maximum for split drum mixers.

Longer holding: For longer periods, the batch may be held in the mixer and turned over at regular intervals, subject to the time limits specified for incorporation of the concrete into the work not being exceeded.

Testing and sampling Discharge: When conducting mixer uniformity tests on a split drum mixer producing centrally mixed concrete, discharge the whole of the batch into the tray of a moving vehicle.

Sample method: Sample the concrete from the tray of the vehicle at points approximately 15 % and 85 % along the length of the tray.

Forming time Maximum forming time: Determine for each nominated mix a maximum forming time by considering the prevailing weather conditions and concrete temperature.

Air temperatures less than 30°C: 90 minutes maximum.

Air temperatures greater than or equal to 30°C: 45 minutes.

Effects on forming time: Reduce forming time as required due to the prevailing weather, mix type, or materials being used as directed.

4.7 PLACING AND FINISHING CONCRETE SUBBASE

Equipment and methods Proposal: Submit the full details of the equipment and methods proposed for placing and finishing the concrete subbase together with a paving plan showing proposed paving widths, sequence and estimated daily outputs. This is a HOLD POINT.

Notice to commence: Give 7 days written notice of the intention to commence construction of the subbase on any section of work including the trial subbase. This is a WITNESS POINT.

Consistency Requirement: Supply concrete of a homogeneous, dense, non-segregated mass with bleeding limited to prevent bleed water flowing over the slab edge under the conditions of placement. If bleed water does flow, cease paving until the consistency of the mix is adjusted to prevent flow or the mix is redesigned and approved.

Concrete edges: Produce the edge so as to maintain its shape with no sag or tear.

Temperature: Test for consistency by the slump test to conform with AS 1379. Measure at the completion of batching as appropriate for the temperature at that time for the concrete as follows:

- Temperature ≤ 25°C: 40 minutes.

- Temperature > 25°C: 30 minutes.

Slump limits: The slump must be within the following limits from the nominated slump:

- 10 mm for slipformed concrete.

- 15 mm for manually placed concrete.

Quality records: Record all results and do not use non-conforming concrete in the works.

Testing: Check the consistency of the concrete by use of a slump cone to AS 1012.3.1 on concrete samples obtained to AS 1012.1. Perform check tests on each truckload of concrete.

Equipment: Provide all equipment, materials and labour for consistency testing.

Test results: Submit all consistency test results as verification. This is a WITNESS POINT.



Evaporation and moisture loss Ground surface conditions: Provide ground surface for the concrete subbase that is damp, clean and free of loose or foreign matter and compacted as approved. This is a WITNESS POINT.

Ambient conditions: Do not place concrete during rain or when the air temperature in the shade is below 10°C or above 30°C, unless appropriate heating or cooling procedures are adopted.

Concrete temperature limits: Within the range 5°C to 35°C.

Records: Measure and record concrete temperature and wind velocity at the point of concrete placement, and continuously measure and record air temperature and relative humidity daily, at the site throughout the course of the work.

Equipment: Provide and maintain all equipment and provide suitable personnel necessary for all such measuring and recording.

Evaporation limit: Take precautionary measures when the value of Rate of Evaporation, as determined from the Rate of evaporation graph, exceeds 0.50 kg/m2/hr. Obtain approval for the methods used to prevent moisture loss or cease work. This is a WITNESS POINT.

Evaporation retarder: If an evaporation retarder is used to prevent excessive moisture loss, apply by fine spray after all finishing operations are complete, except minor manual bull-floating. Re-application of evaporation retarder after level floating may be directed as required.

Rate of evaporation graph

Using the Rate of evaporation graph Information: The graph shows the effects of air temperature, humidity, concrete temperature and wind velocity on the rate of evaporation of water from freshly placed and unprotected concrete.



Example: To determine the evaporation rate from the graph using air temperature at 27°C, relative humidity at 40%, concrete temperature at 27°C and a wind velocity of 26 km/h:

- Enter the graph at the air temperature of 27°C.

- Move vertically to intersect the curve for relative humidity encountered 40%.

- Move horizontally to the respective line for concrete temperature of 27°C.

- Move vertically down to the respective wind velocity curve and interpolate for 26 km/hour.

- Then move horizontally to the left to intersect the scale for the rate of evaporation.

- The rate of evaporation would be 1.6 kg/m2/hour in this example.

Paving in general

Surface texture:

- Generally: Steel screed or float finish.

- For asphaltic concrete overlay: Hessian dragged finish.

Surface finish: If the subbase will not have a sprayed bituminous seal and is to be covered by concrete base, the surface must be smooth and without dimpling, ridges or recesses. Nonconforming areas must be treated prior to base paving to achieve a smooth surface.

Concrete finish: Dense and homogeneous with a surface exhibiting low permeability.

Base slab anchors: During construction of the subbase ensure to make provision to permit the construction of base slab anchors at the locations shown on the drawings. This is a WITNESS POINT.

Continuity: Once spreading commences adopt a continuous concrete paving operation. Ensure a continuous supply of concrete so that the forward progress of the mechanical paver is not stopped due to lack of concrete.

Disruptions: If disruptions occur for any reason in both mechanical and hand paving, a direction may be given to form a construction joint before the recommencement of paving operations. This is a WITNESS POINT.


Mechanical paving Paver machine: The mechanical paver to conform to the following:

- A self-propelled machine with a gross operating mass of not less than 4 tonnes per lineal metre of paved width.

- Capable of paving at a speed of one metre per minute or less as required to enable the continuous operation of the paver and obtain the required degree of compaction.

- Include an automatic control system with a sensing device to control line and level to the specified tolerances.

- Able to spread the mix uniformly and regulate the flow of mix to the vibrators without segregation of the components.

- Contain internal vibrators capable of compacting the full depth of the concrete.

- Contain an adjustable extrusion screed and/or conforming plate to form the slab profile and produce the required finish on all surfaces.

- Capable of paving in the slab widths or combination of slab widths and slab depths shown on the Drawings.

Concrete finish: Place the concrete with the mechanical paver to allow for the minimum finishing by hand.

Supporting surface: Provide a supporting surface for the tracks of the paver, curing machine and any other equipment in the paving and curing train to be in a smooth and firm condition.

Hand placing Restriction: Use hand placement only in areas where mechanical placement is impracticable or where approved prior to commencement of work.

Formwork: Provide formwork as follows:

- Designed and constructed so that it can be removed without damaging the concrete.

- True to line and grade.

- Braced in a manner suitable for the support of wet concrete.

- Mortar tight and debonded to ensure non-adhesion of concrete to the forms.



Placing in forms: Deliver concrete in agitator trucks and deposit uniformly in the forms without segregation.

Compaction: Compact the concrete by poker vibrators and by two passes only of a hand-guided vibratory screed traversing the full width of the slab on each pass.

Buildup: Prevent any buildup of concrete between the forms and vibratory screed.

Standby vibrators: Require minimum of 1 standby vibrator and ¼ of the vibrator number in use.

Vibrators: Not less then 1 internal vibrators for each 10 m3 of concrete placed per hour. For paving widths greater than 2.5 m a minimum of 2 vibrators must be used.

Screed: Compact and finish the slab by at least 2 passes of a hand guided vibratory screed traversing the full width of the slab on each pass.

Alignment and surface tolerances Outer edge: Construct outer edges of the subbase to be square to the subgrade and 50 mm wider than the plan position of the base formation with a tolerance of ± 25 mm.

Longitudinal construction joint: If an edge of a slab is to form a longitudinal construction joint line to conform to Longitudinal construction joints for the allowable horizontal alignment tolerances.

Subbase tolerance: +0 mm to –20 mm deviation from the design level.

Finished surface tolerance: ± 5 mm deviation from a 3 m straight edge.

Remedial works: Remove concrete found to be above level. If concrete is found to be below level tolerance, make it up with base concrete. This is a WITNESS POINT.

Protection of work Temperature control: Ensure that the temperature of the concrete does not fall below 5°C during the first 24 hours after placing.

Submit: Provide details of procedures and equipment proposed to be used for the protection of sections recently placed in the event of low air temperatures.

Non compliance: If the temperature of the concrete is not maintained at or above 5°C and if the concrete exhibits any deficiencies that may be due to the failure to conform to this Worksection, the concrete will be rejected. This is a WITNESS POINT.

Rain protection: Protect the work from rain damage and submit detailed proposals for procedures and equipment to be used for such protection.

Traffic considerations Traffic restrictions: Do not allow traffic or construction equipment, other than that associated with testing, on the subbase until the strength of the subbase has reached at least 4.0 MPa.

Initial strength: Permit traffic after initial strength is reached only from equipment necessary for the following operations:

- Bond-breaker and spall treatment.

- Concrete or asphalt paving.

Damage Rectification Damage: Rectify any damage caused to the subbase by the Contractor’s operations at any time to the Superintendent’s satisfaction.


4.8 JOINTS

General Confirm: The location and condition of construction joints. This is a WITNESS POINT.

Transverse construction joints Comply with the following:

- Do not scabble.

- Provide only at discontinuities in the placement of concrete determined by paving operations.

- Construct normal to the edge line and to the dimensions shown on the Drawings.

- Do not deviate from a 3 m straightedge placed along the joint by more than 10 mm, having made due allowances for any planned curvature.

- Make smooth across the joint.



Longitudinal construction joints Comply with the following:

- Form no closer than 300 mm of the base longitudinal joints as shown in the Drawings, unless directed otherwise.

- Do not deviate from the plan or nominated position at any point by more than 20 mm.

- Do not deviate from a 3 m straightedge placed along the joint by more than 10 mm, having made due allowances for any planned curvature.

- Make smooth across the joint.

- Make perpendicular to the subgrade surface.

4.9 CURING AND DEBONDING

Curing Curing compound application method: Fine spray immediately following texturing at the rate stated on the certificate of compliance or at a minimum of 0.2 litres/m2, whichever rate is the greater.

Bitumen emulsion application method: Minimum rate of 0.5 litres/m2 of residual bitumen.

Hand application: If application is with a hand lance increase the rates by 25%.

Application rate: Check the average application rate and certify to the Superintendent by calculating the amount of curing compound applied to a measured area representative of a lot nominated by the Superintendent. This is a WITNESS POINT.

Curing period: Maintain the curing membrane intact for seven days after placing the concrete.

Damage: Make good any damage to the curing membrane by hand spraying of the affected areas.


Equipment on site: Keep equipment and materials for curing operations on site at all times during concrete placement.

Application of bond breaker Requirement: If the base consists of asphaltic concrete do not use wax emulsion curing compounds.

Preparation: Immediately prior to the application of bond breaker, clean the subbase surface of all loose, foreign and deleterious material to the satisfaction of the Superintendent.

Second application (after curing): Minimum rate of 0.2 litres/m2, not earlier than 72 hours before the placement of the base concrete.

Method: The method of application to conform to Curing. Debonding treatment: Apply a debonding treatment to the top surface of the subbase additional to the curing treatment applied.

Timing: Apply debonding treatment after the subbase has achieved strength of 4.0 MPa and the subbase level schedules have been completed. Complete treatment within 49 days of placement of the subbase or within 14 days of the achievement of strength conformity, whichever occurs first.

4.10 CONCRETE CRACKING

Typical subbase cracking Acceptable: Full-depth transverse cracks continuous for the full width of the paving run at approximately 4 m centres. This is not considered nonconforming unless subsequent deterioration occurs prior to being covered with base.

Plastic shrinkage cracks Discrete cracks: Plastic shrinkage cracks are discrete cracks of length less than 300 mm and a depth less than 50 % of the slab thickness that do not intersect a formed edge. No remedial action is required if a bond breaker is applied. Implement immediately the corrective action.

Additional longitudinal and transverse cracks Limit: Subbase cracking other than typical cracking and plastic shrinkage cracks is considered nonconforming if the cumulative length of cracking in any 25 m2 area of subbase exceeds 2 m. Implement immediate corrective action.

Corrective action Methods: Conform to the following:

- Apply an approved 300 mm minimum width geotextile backed polymer modified bitumen strip over the crack prior to placement of the first asphalt base layer or concrete base. Install the Stress



Alleviating Membrane strip in accordance with the manufacturer’s instructions. (see AUSTROADS AGPT04G).

- Apply extra wax emulsion for a width of 300 mm along the crack when a concrete base is required. Provide extra application of wax emulsion to ensure a doubling of the application rate over the strip width.

Rejected concrete Criteria: Remove and replace slab areas where one or more of the following occurs:

- Transverse cracking over 300 mm in length occurs at average spacing less than 2 m over a length of 5 metres.

- Longitudinal cracking for a contiguous length exceeding 5 metres.

- Cracking over 300 mm in length within a distance of 1.5 metres from a construction joint, isolation joint or free edge. This is a WITNESS POINT.


Treatment of spalling Preparation of subbase: Immediately prior to spalled area treatment, clean the subbase surface of all loose, foreign and deleterious material to the satisfaction of the Superintendent. Wet the area and sprinkle with neat cement. This is a WITNESS POINT.

Spalling: If the spalled area is greater than 10 mm deep and 15 mm wide infill the area with 6:1 sand/cement mortar and screed the surface flush with the surrounding concrete.

Spalled full-depth cracks: Full-depth cracks that have spalled more than 10 mm deep and 15 mm wide must be infilled with a flexible sealant to provide a surface flush with the subbase surface.

Spalling repair time: Complete treatment no earlier than five working days before the application of the bond breaker.


4.11 ACCEPTANCE OF CONCRETE STRENGTH AND THICKNESS

Cylinder strength testing (in the trial mix) Mix adjustment: Determine any need for mix adjustment throughout the progress of the work by carrying out a statistical check of the compressive strength of concrete.

Statistical check: Use consecutive 28 day test results representing 1000 m3 concrete placed in the work for each approved mix.

Analysis: Analyse test results on the basis of groups of consecutive pairs of specimens, and submit the results within five weeks of the last placement included in the analysis.

Mix acceptance: The concrete mix and its method of production are satisfactory if the average compressive strength of any six consecutive pairs of specimens is within the range specified for maximum and minimum compressive strength.

Modification: If any of the above compressive strength conditions are not met, modify the mix and/or improve the method of production of concrete. This is a WITNESS POINT.

Concrete cylinders Test specimens: Collect standard cylinders to conform with AS 1012.8.1 and submit test results. This is a WITNESS POINT.

Moulds: Supply a sufficient number of moulds to meet the requirements for the frequency of testing specified in this Clause and also arrange for a NATA laboratory to conduct the sampling of fresh concrete, curing, delivery and testing of specimens.

Sampling: Take samples of concrete for testing to AS 1012.1. Select the batches to be sampled randomly. Mould the specimens from each sample so that they are as identical as practicable.

Specimens: Make and cure the specimens to AS 1012.8.1 with compaction by internal vibration. Mark the specimens for identification.

Test method: Inspect, cap and crush specimens to AS 1012.8.1 and AS 1012.9. Do not transport specimens within 3 hours of being cast.

Frequency: Mould one pair of test specimens for each lot for compressive strength at early age, 7 days or 28 days.



Compressive strength of concrete Average: Determine the average compressive strength of two specimens from compressive strength of the concrete measured for a pair of specimens moulded from one sample.

Acceptance criteria: At the time of approving the mix design, the Superintendent to nominate whether 7 day or 28 day compressive strength or both are the acceptance criteria for strength.

Adjustment due to age: Should any specimen be tested more than 28 days after moulding, the equivalent 28 day compressive strength is to be the test compressive strength divided by the factor applying to the age of the specimen at the time of the test shown in the Concrete age conversion factors table. For intermediate ages determine the factor by interpolation.

Concrete age conversion factors table

Age of specimen at time of test (days) Factor

28 35 42 49 56 70 84 112 140 168 196 224 308 365 or greater

1.00 1.02 1.04 1.06 1.08 1.10 1.12 1.14 1.16 1.18 1.20 1.22 1.24 1.25

Non conformance: If the compressive strength of test cylinders for any lot is less than the criteria specified in Compressive strength, remove the lot represented by the test cylinders and replace in accordance with this worksection.


Testing by specimens cut from the work Coring test: In the case of non-conforming test cylinders, the Contractor may request permission to core the in situ subbase for testing of the actual compressive strength representing the particular lot. The locations for testing will be nominated by the Superintendent.

In situ testing: Do not retest subbase concrete failing to reach the required in situ compressive strength for at least 72 hours after the determination of the value of the in situ compressive strength. This is a WITNESS POINT.

Test specimens: Cylindrical cores of hardened concrete cut from the work and tested in a NATA registered laboratory nominated by the Contractor.

Frequency of coring: Adopt a frequency of coring such that a core is taken to represent each lot or the subbase placed between any two consecutive construction joints whichever is the lesser. Nominate the lot represented by each core at the time of sampling and duly record prior to testing.

Supervision: Carry out core cutting in the presence of and at the locations nominated by the Superintendent. This is a WITNESS POINT.

Curing of cores: Despatch cores to arrive at the testing laboratory within 24 hours of the core being cut from the subbase. Commence wet curing within 24 hours of the receipt of the cores.

Requirement: The Contractor will bear the cost for cutting and transporting the cores to the testing laboratory and restoring all holes in the subbase.

Test method: To AS 1012.14 with the following amendments:

- The requirement that the concrete is to be at least 28 days old before the core is removed is not to apply. However, concrete must have hardened enough to permit removal without disturbing the bond between the mortar and the coarse aggregate.

- The preferred dimension for cores is 100 mm diameter but in no case is the diameter to be less than 75 mm or two and one half times the nominal size of the coarse aggregate, whichever is the greater.



- If inspected in the uncapped state, reject cores if any diameter departs by more than 5 mm from the mean diameter.

- Reject cores where the length of the core when ready for capping is less than the diameter.

- Adjust the test strength determined for form by a factor to conform with Core strength factor table.

- Use wet conditioning only.

Core strength factor table

Length/diameter ratio Correction factor

2.00 1.00

1.75 0.98

1.50 0.96

1.25 0.93

1.00 0.89

Use interpolation for intermediate form ratios.

Restoration after coring: Use an approved restoration method. This is a WITNESS POINT. - Costs: Borne by the Contractor.

Acceptance of cored concrete for compressive strength Strength requirement: 5 MPa within 28 days of placement.

Core strength: If the specimen cut from the subbase reaches 4 MPa for in situ compressive strength, proceed with base paving.

Rejected concrete: Remove and dispose of rejected concrete and any bond breaker.

Costs: Born by the Contractor.

Conformance for thickness Conforming tolerances: Do not carry out thickness measurements if the surface of the subbase is within the level tolerances as specified in Alignment and surface tolerances.

Thickness measurement: If scabbling is required to achieve the level tolerance limits, the Superintendent may order thickness checks to be carried out.

Subbase thickness determination: Assess the thickness by survey level runs after placement, taken on a 5 m grid on the plan area, comparison to the subgrade survey round off to the nearest 5 mm. This is a HOLD POINT.

Verification alternative: Cutting concrete cores or measurements at subbase edge, as directed.

Subbase design level: Determine the design level of the top of the subbase from the design level of the finished road surface less the thickness of the base course and the wearing course.

Subbase tolerance: + 10 mm/- 20 mm deviation from the design level.

Finished surface tolerance: ± 10 mm deviation from a 3 m straight edge.

Thickness for tolerance: ± 10 mm.

Accepted tolerance: Subbase which is 10 mm or less below the theoretical thickness may be accepted providing that it represents isolated sections within a lot and such sections comprise less than 5 % of the area of the lot.

Insufficient thickness: After making due allowance for the tolerances, subbase which is more than 20 mm below the theoretical thickness will be rejected and removed from the site. This is a WITNESS POINT.


4.12 REMOVAL AND REPLACEMENT OF SUBBASE

General Rejected Subbase: Remove rejected subbase and replace to conform with this Clause. Replace rejected subbase, which extends more than 25 m longitudinally by mechanical means unless the slabs are odd-shaped or mismatched.

Proposed method: Submit details of the proposed methods of carrying out the work that will prevent damage to the adjoining subbase. This is a HOLD POINT.




Subbase sawcuts Transverse sawcut:

- Make a transverse sawcut the full depth of the subbase layer at each end of the section of subbase to be removed.

- Make the sawcut normal to the control line.

- Do not over-saw into the adjoining base or underlying sub base.

Longitudinal sawcuts:

- Locate the cut 150–300 mm offset from planned longitudinal contraction joints in the overlying base.

- Do not to extend more than 250 mm past the transverse sawcut at each end of the section to be removed.

Over-sawing: Do not over-saw on any additional internal sawcuts made to aid the removal of the subbase.

Removal and replacement Disposal: Dispose of the removed base slabs as approved.

Damage to adjoining pavement: Remove and replace any pavement adjacent to the original area of rejected subbase damaged by the operations. This is a WITNESS POINT.

Replacement of bondbreaker: After construction of the replacement subbase, prepare and debond the pavement in accordance with this worksection.

4.13 LIMITS AND TOLERANCES

Application Summary: The limits and tolerances applicable to this worksection are summarised in Summary of limits and tolerances table.

Summary of limits and tolerances table

Activity Limits/Tolerances Worksection Clause/ subclause

Materials for concrete

Properties for coarse aggregates To the Coarse aggregate properties table

Aggregates/ Coarse aggregate

Aggregates grading Deviation from submitted sample not greater than Fine aggregate grading table

Aggregates/ Fine aggregate

Concrete

Drying Shrinkage at 21 days: - Maximum aggregate size > 20 mm - Maximum aggregate size 20 mm

maximum 450 µε maximum 500 µε

Concrete quality requirements/ Drying shrinkage

Consistency Mechanically placed: 25 mm to 40 mm Hand placed: 50 mm to 65 mm

Concrete quality requirements/ Consistency

Air content 3% to 7% Concrete quality requirements/ Air content

Thickness Remove concrete if thickness > 20 mm below specified thickness.

Acceptance ofconcrete strength and thickness/ Conformance for thickness



Activity Limits/Tolerances Worksection Clause/ subclause

Mixing and transport After addition of cement to the aggregate incorporate concrete into the work within: - 90 minutes where transported by truck

mixer or agitator. - 60 minutes where transported by non

agitating trucks.

Production and transport of concrete/ Agitation

Placing Do not place concrete when the air temperature in the shade is < 5°C or > 38°C. Temperature of concrete > 10°C but < 32°C.

Placing and finishing concrete subbase/ Evaporation and moisture loss Do not place concrete when the Rate of

Evaporation exceeds 0.50 kg/m²/h.

Alignment and surface tolerances

Horizontal alignment Outer edges not to deviate from plan position by more than 25 mm.

Placing and finishing concrete subbase/ Alignment and surface tolerances

Vertical alignment - subbase Level on top surface: + 0 mm to - 20 mm deviation from that shown on the drawings.

Surface finish Top surface: ± 5 mm deviation from a 3 m straightedge laid in any direction

Joints

Transverse construction joints ± 10 mm deviation from a 3 m straight-edge placed along the joint.

Joints/ Transverse construction joints

Longitudinal joints - Do not deviate from the plan or nominated position at any point by more than 20 mm.

- ± 10 mm deviation from a 3 m straight-edge placed along the joint after allowing for any curvature.

Joints/ Longitudinal construction joints

Bond breaker

Wax emulsion Minimum 0.2 l/ m², not earlier than 72 hours before placement of base.

Curing and debonding/ Application of bond breaker

5 MEASUREMENT AND PAYMENT

5.1 GENERAL

Payment shall be made for all the activities associated with completing the work detailed in this worksection and shown on the drawings, in accordance with provisions made in Contract Document.