Specification - Tunnel Shotcrete Lining

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Thiess John Holland

Joint Venture

Airport Link | Northern

Busway | EWAG

GL - Supplementary

Specification - Tunnel -

Shotcrete Lining

GLTSP102

Document ref

BC-PBA-GLTSP102-SPC-0001-1-03

26 May 2010

DCN: 00047

IFA / AFC

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Thiess John Holland

Joint Venture

Airport Link | Northern

Busway | EWAG

GL - Supplementary

Specification - Tunnel -

Shotcrete Lining

GLTSP102

May 2010

Parsons Brinckerhoff Arup Joint Venture ABN 88 642 968 608 Parsons Brinckerhoff Australia Pty Ltd ABN 80 078 004 798 Arup Pty Ltd ABN 18 000 966 165

This report takes into account the particular instructions and requirements of our client.

It is not intended for and should not be relied upon by any third party and no responsibility is undertaken to any third party

Parsons Brinckerhoff Arup Joint Venture

Level 6 515 St Paul's Terrace, Fortitude Valley QLD 4006, PO Box 3546 South Brisbane BC QLD 4101

Tel +61 7 3309 7500 Fax +61 7 3309 7890 Job number PB2108209A

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Document Verification

Page 1 of 1

Job title Airport Link | Northern Busway | EWAG Job number

PB2108209A A125840 Document title GL - Supplementary Specification - Tunnel - Shotcrete Lining

GLTSP102

File reference

Document ref BC-PBA-GLTSP102-SPC-0001-1-03 26 May 2010 Revision Date Filename BC-PBA-AGTSP100-SPC-0002-0-01.doc AFC Issue 25/02/09 Description AFC Issue

Prepared by Checked by Approved by Name Andreas Amon Robert Bertuzzi Eddie Woods

Signature

Review 16/02/10 Filename BC-PBA-GLTSP102-SPC-0001-1-01.doc Description Issued for Review, DCN: 00047, Refer to Table 2

Prepared by Checked by Approved by Name Eddie Woods Richard Page Eddie Woods

Signature

Review 29/03/10 Filename BC-PBA-GLTSP102-SPC-0001-1-02.doc

Description Issued for External Review, DCN: 00047, Refer to Table 2

Signature

IFA / AFC 26/05/10 Filename BC-PBA-GLTSP102-SPC-0001-1-03.doc

Description Issued for IFA / AFC, DCN: 00047, Refer to Table 2

Signature

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GL - Supplementary Specification - Tunnel - Shotcrete Lining GLTSP102

1 General

This technical specification has been provided by Parsons Brinckerhoff Arup Joint Venture on behalf of Thiess John Holland Joint Venture for use in execution of the Design and Construct Contract with the Airport Link, Northern Busway and ARU project (the Project).

1.1 Scope

This specification supersedes Shotcrete Lining (reference AGTSP100-0002).

This Specification applies to the manufacture, supply and application of shotcrete for the temporary and permanent (pump sumps and substations) shotcrete lining of the Airport Link and Northern Busway tunnels. In addition, this document specifies the performance based requirements for shotcrete and details the testing requirements to ensure that the shotcrete applied on site is consistent with these performance requirements.

For this Project, shotcrete is concrete with or without admixtures pneumatically applied to a prepared rock surface, in and around steel sets, or in and around lattice girders.

The scope of this Specification comprises:

• steel or synthetic fibre reinforced shotcrete (SFRS),

• steel mesh reinforced shotcrete

• and plain or unreinforced shotcrete (URS)

• plain shotcrete with polypropylene fibres to provide fire protection

• aggregates for use in permanent shotcrete requiring fire resistance

The specification covers both temporary works shotcrete and permanent shotcrete. The specification complies with the Mined Tunnels Design Manual and will be reviewed and updated as necessary during execution of the Works.

The types of shotcrete for underground works are as follows:

• SFRS applied as temporary (initial) and permanent (pump sumps and substations) ground support

• URS applied as a smoothing layer prior to installation of the tunnel waterproofing membrane or providing an initial layer in combination with mesh reinforcement prior to application of permanent lining or as a finishing layer for permanent ground support (pump sumps and substations).

This Specification shall be read in conjunction with the Temporary and Permanent Works Design Drawings and other relevant Specifications. The thickness dimensions shown on the Drawings are minimum thicknesses. Shotcrete thicknesses shall be such as to provide a minimum cover, as shown on the Drawings, over all steel components and fixtures including rockbolt heads, steel sets, lattice girders and reinforcing mesh.

The General Specification (reference BC-PBA-GLRSP000-SPC-0001) provides general information relating to all other specifications. The General Specification must be used with this Specification.

Users of this Specification and related specifications and documents are required to ensure, that they are referring the current version.

The durability of shotcrete manufactured in accordance with this specification has been assessed in the Durability Report (reference PBA-BC-AGDTR100-RPT-0001).

This specification is to be read in conjunction with the related specifications outlined in Clause 1.3.

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1.2 Definition of Terms

Definitions applicable to many specifications, including this Specification, shall include those found in the General Specification (reference BC-PBA-GLRSP000-SPC-0001).

While the definitions found in the General Specification take precedence, the following definitions, when not found in the General Specification, apply particularly to this Specification:

Table 1 – Definition of Terms

Term Definition

Relative Strength for Silica Fume

The relative strength for silica fume is the ratio (in percent) of the

compressive strength of standard mortar bars, prepared with 90% cement plus 10% silica fume by mass, to the compressive strength of standard mortar bars made from cement only.

Admixtures Materials added to base concrete such as accelerators and hydration control mixtures. (Note that silica fume, plasticisers and retarders may be included in Base Concrete if proposed to be used in the Temporary and Permanent Works shotcrete).

Cement An active hydraulic binder formed by grinding clinker and conforming to AS 3972. Cement and cementitious content exclude the mass of silica fume. Characteristic

Cylinder strength at 28 days

The value of the standard cylinder strength at 28 days below which 5% of the population of all possible strength measurements are expected to fall. (Characteristic cylinder strengths are quoted in the Specification for the purpose of the development of mix design only).

Curing The control of temperature and moisture in the concrete until the concrete has developed required properties.

Flash Coat Sprayed concrete applied as a thin layer protecting, priming or finishing the surface of the tunnel. A flash coat shall be at least 20mm thick.

In Situ Cylinder Strength

The notional strength of shotcrete at a single location, considered as the strength of a cylinder of shotcrete as it exists in the structure. In situ cylinder strengths are given in the Specification for the purpose of compliance requirements.

Lattice Girder A lightweight, three dimensional steel or fibreglass frame made to act as a unit by connecting all components with lacing bars; used in conjunction with shotcrete for shotcrete lining reinforcement.

Layer A discrete thickness of sprayed concrete built up from a number of passes of the nozzle which is allowed to set.

Nozzle Attachment at end of delivery hose from which shotcrete is projected. Overspray Material projected outside the intended receiving surface.

Rebound Shotcrete which having passed through a spraying nozzle does not adhere to the surface to which shotcrete is being applied.

SFRS Steel fibre reinforced shotcrete

Silica Fume Concrete Concrete manufactured by combining cement complying with AS 3972 with silica fume. The Contractor shall ensure that sufficient lime is available for reaction with the silica fume, particularly when sulphate resistant cement or pulverised fuel-ash is used.

Sloughing Subsidence of fresh shotcrete.

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Term Definition

nozzle into place to produce a dense, homogeneous mass, applied directly to the ground surface in one or more layers to form the lining of a sprayed concrete support structure.

Shotcrete Type S1 Steel fibre reinforced shotcrete (SFRS) which is applied as initial or primary ground support and is designed to carry temporary loads only.

Shotcrete Type S2 Steel mesh reinforced shotcrete (SMRS) which is applied as initial or primary ground support and is designed to carry temporary loads only. Shotcrete Type S3 Un-reinforced shotcrete (URS) which is applied as initial or primary ground

support and is designed to carry temporary loads only.

Shotcrete Type S4 Un-reinforced shotcrete (URS) which is applied as backfill shotcrete, smoothing shotcrete and/or as a protective layer to shotcrete Type S1, P1 or bare rock, and is designed to carry temporary loads only.

Shotcrete Type P1 SFRS which is applied as permanent ground support and is designed to carry permanent loads.

Shotcrete Type P2 SMRS which is applied as permanent ground support and is designed to carry permanent loads.

Shotcrete Type P3 Plane shotcrete used as a smoothing layer and to provide fire protection Shotcrete Mix Terms Base Mix: Concrete designed, tested and supplied independent from the

shotcreting process, equipment and personnel.

Shotcrete Mix: The base mix after it is applied to the Works, or to test panels.

Sprayed Concrete Support Systems Structure

A structure built underground in accordance with this specification.

Standard Cylinder strength

The measured compressive strength of a cylinder made, cured and tested in accordance with AS 1012.8 and AS 1012.9 for cast samples and in accordance with AS 1012.14 for cored samples.

URS Unreinforced Shotcrete

Waterproofing Supervisor

As defined in the Waterproofing and Drainage Specification (reference BC-PBA-GLTSP107 SPC-0001).

Wet-mix Process The process of producing shotcrete in which cement and aggregate are weigh batched and mixed with water at or near the shotcreting location or in mixer trucks prior to being pumped through a pipeline to a nozzle where compressed air, and admixtures if necessary, are injected and the mix projected into place without interruption.

1.3 Standards and Related Specifications 1.3.1 General Specification

The General Specification (reference BC-PBA-GLRSP000-SPC-0001) contains information required for an understanding of any and all of the specifications applicable to the Project. The General Specification shall be read prior to use of any of the other specifications, including this Specification.

1.3.2 Standards and Related Specifications

This specification is to be read in conjunction with the following:

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BC-PBA-GLTSP101-SPC-0001 Global – Supplementary Specification – Tunnel - Rock Reinforcement

BC-PBA-GLTSP102-SPC-0001 Global – Supplementary Specification – Tunnel - Mined Tunnel Excavation and Implementation

BC-PBA-GLTSP106-SPC-0001 Global – Supplementary Specification – Tunnel – Cast in Place Concrete

BC-PBA-GLRSP009-SPC-0001 Global – Supplementary Specification – Road – Projectwide Instrumentation and Monitoring

BC-PBA-GLTSP107-SPC-0001. Global - Supplementary Specification – Waterproofing and Drainage

BC-PBA-AGDTR100-RPT-0001 – Durability Technical Report

PSTS

PSTS01 Introduction to Technical Standards

PSTS03 Drainage, Retaining Structures and Protective Treatments

PSTS50 Specific Quality System Requirements

PSTS70 Concrete

PSTS71 Reinforcing Steel

Australian Standards

AS 1012 Methods of Testing Concrete

AS 1141 Methods for Sampling and Testing Aggregates

AS 1379 Specification and Supply of Concrete

AS 1478.1 Chemical Admixtures for Concrete

AS 2350 Methods of Testing Portland and Blended Cements

AS 2758.1 Aggregates and Rock for Engineering Purposes – Concrete Aggregates

AS 3582.1 Supplementary cementitious materials for use with Portland and blended

cement – Fly Ash

cement – Slag – Ground Granulated Iron Blast Furnace

cement – Silica Fume

AS 3583.6 Methods of test for supplementary cementitious materials for use with

portland cement

AS 3972 Portland and Blended Cements

AS/NZS 4671 Steel Reinforcing Materials

AS/NZS ISO 9001 Quality Management Systems – Requirements

ASTM Standards

ASTM A820 Standard Specification for Steel Fibres for Fibre-Reinforced Concrete

ASTM C1260 Standard Test Method for Potential Alkali Reactivity of Aggregates

(Mortar-Bar Method)

ASTM C1550 Standard Test Method for Flexural Toughness of Fibre Reinforced

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ASTM C311 Standard Test Methods for Sampling and Testing Fly Ash or Natural

Pozzolans for Use in Portland-Cement Concrete

ASTM C94 Standard Specification for Ready-Mixed Concrete

British Standards

BS EN 1367-2 Tests for Thermal and Weathering Properties of Aggregates

BS EN 14488-4 Testing sprayed concrete. Bond strength of cores by direct tension BS EN 14488-7 Testing sprayed concrete. Fibre content of fibre reinforced concrete

BS EN 14889-1 Fibres for concrete - Part 1: Steel fibres - Definitions, specification and conformity

BS EN 14889-2 Fibres for concrete - Part 2: Polymer fibres - Definitions, specification and conformity

Other Standards

ACI 506R-05 Guide to Shotcrete

Specification for Tunnelling, British Tunnelling Society and the Institution of Civil Engineers ITA-shotcrete guidelines, Sprayed concrete for final linings: ITA working group report, AITES / ITA, 2001

Concrete Institute of Australia, Recommended Practice – Shotcreting in Australia

1.4 Discrepancy Between Drawings and Specification

Where a discrepancy exists between the Design Drawings and this Specification the Contractor shall seek clarification from the Construction Certifier. Drawing notes will take precedence over the Specification.

1.5 Changes to previous revisions

The following table details all the changes made to this specification since previously issued revisions.

Table 2 – Changes made to previously issued revisions

Revision Clause Change Description

Description

1-01 DCN: 00047

General Modification Paragraphs and lists numbered for ease of referencing

Section 1 – Sections reorganised inline with the new specification template.

1.1 Modification Minor text changes clarifying scope

1.1 Modification Addition of last 2 bullet points to first set of bullet points, First sentence of 5th paragraph added, and additional text added to the last bullet point in second set of bullet points.

1.2 Modification Activity Index for Silica Fume has been amended to Relative Strength, SFRS definition added,

Shotcrete Type P3 definition added and URS definition added.

1.3 Addition Addition of reference AS 3583.6

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the report.

3.2 Modification Addition of the final bullet point added

3.5.2 a)

I.

Deletion Text deleted – (undensified)

3.5.2 Modification I,vi changed from Silica activity index to relative strength and reference added.

3.6 v. Addition Text added – “For aggregates comprising volcanic breccia, mudstone, shale, sandstone, weathered or altered rocks”

Bullet Points added

3.6 Modification Table 8 revised. S3 put in column one for % passing and S4 replaces S3 for % passing. 3.8.2 e) Addition Text added – “The Contractor shall test selected

types of accelerators for the range of ±2% in 5.0%, 8.0% dosages or the manufacturer’s recommended dosage to ensure the short and long term strength is not impaired and meets the specified

requirements”

3.10 Addition Text added – (permanent shotcrete only)

4.1 Addition Section 4.1 Inserted

4.2 Modification Witness point added

Section moved from Section 4.1 to 4.2 4.3 vi. Addition Text added – (for permanent shotcrete only) 4.4. ( b) Modification

Addition

Text modified and added – “The target slump(s) shall be determined by trial mixes with and without superplasticisers provided the pre production and production tests show that the sprayed concrete achieves the short and long term strengths specified in Table 13 for field tests and production tests (cores), for sprayed concrete the target slump shall be;

Without superplasticiser: 80 to 120mm With superplasticiser: 80 to 150mm”

4.4.( i) Addition Text added – (a spare specimen shall be taken but not tested)

4.4 (n) Addition Text added – “The Contractor shall provide 1,7,28 & 90 day strength verses time curves for cores taken directly from the tunnel lining together with early strength results (less than 1 day) for beam end test verses needle penetrometer tests”

4.6 Modification Table 13 updated –

Field trials and Production Tests (Cylinder) updated Dry density 2150 to 2400Kg/m³

- “for permanent shotcrete only “added to Boiled Absorption and Apparent Volume

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GL - Supplementary Specification - Tunnel - Shotcrete Lining GLTSP102 Note (1) added clarifying purpose of maximum strength

Addition of “Fire Performance of P3 shotcrete” row 5.3 Addition (a) text added in first paragraph

Clause 5.3.1 Smoothing Shotcrete section added 6.3 f) Addition Text added – “however, using a drop pipe to

transfer the concrete from the surface underground into an agitator truck is acceptable provided the material does not become overly segregated and remixing produces a homogenous sprayable mix.” 7.1

(Table 14)

Modification Requirement for 1 day tests deleted (as covered by beam end tests)

Compressive strength test changed to a cylinder sample

Deletion of Boiled Absorption and Voids Volume 7.1

(Table 15)

Modification Requirement for 1 day test deleted as covered by Early age compressive strength test

Compressive strength test changed to a cylinder sample

Boiled absorption test required for permanent shotcrete only

Flexural strength test method added.

1-02 DCN: 00047

1.1 Addition Addition of text – “The durability of shotcrete…..”

1.2 Modification Definition of Silica Fume Concrete has been modified. Wording used now has been modified from comment response for clarity.

1.2 Addition Addition of Waterproofing Supervisor definition

1.3 Addition Addition of references to Waterproofing and

Drainage specification and Durability Report.

3.6 Modification Table 8 updated – P3 added into column

3.8.2 Modification Addition of text – “But shall not exceed”

3.8.4 Modification Part C changed to include P3

3.9 Addition/Modification Structure changed around to include new headings. 3.9.1 General, 3.9.2 Steel Fibres etc.

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4.2 Modification Addition of column to Table 11 of P3

Table 11 Modification No change to content but Table has been reformatted for clarity.

4.4 b Modification “Determined” has been replaced with “confirmed”

5.3 Addition Addition of text – “as required by the

Waterproofing….”

5.3.1 Deletion Deletion of 5.3.1 Part b part iii.

5.3.1 Modification Text modified to say “manufacturer’s”

6.1 Addition Addition of P3 to 1st paragraph

General Modification Where items have been shown for the approval of the Designer, this should have referred to the Construction Certifier. This general error has been corrected throughout the document.

General Modification Formatting and grammatical errors have been amended for the IFA / AFC issue.

1.6 Records Maintained by the Contractor

a) General guidelines for records are provided in the General Specification (reference BC-PBA-GLRSP000-SPC-0001).

b) Records of work methods, listed in Table 6 related to this specification are required to be submitted by the Contractor to the Construction Certifier in accordance with the quality system requirements of the Contract.

c) This Specification requires the Contractor to prepare and maintain, as a minimum, the following documents in accordance with the Contractors Project Quality Plan and make them available for audit purposes:

i. Proposals to adopt alternative materials and equipment

ii. All information necessary to produce as-built drawings and records

iii. Details of cement for shotcrete, including suppliers details and information to demonstrate compliance with AS 3972

iv. Details of fly ash, slag and silica fume for shotcrete

v. Details of aggregates and aggregate sources for shotcrete, including testing and properties of the aggregates

vi. Manufacturer’s test certificates and product analysis certificates for the fibres to be used for the fibre reinforced shotcrete

vii. Test results for the water used in the mixing and curing of the shotcrete

viii. Concrete Supplier’s batch card showing details of the mix design for each type of shotcrete

ix. Details of all admixtures for shotcrete, including manufacturer’s product data, and the equipment and method of controlling the addition of admixtures to the shotcrete x. Records of the type of equipment used for batching, mixing, transport and

application of shotcrete, including location of the batching plant and method of delivery to site

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xi. Results of all acceptance testing and field trials, and results of production testing of the shotcrete

xii. The mix design for each type of shotcrete shall be approved by the Construction Certifier.

xiii. Records of inspection and written approval of the Temporary and Permanent Works shall be provided in accordance with this Specification.

2 Quality System Requirements

2.1 General

a) Specific quality system requirements are detailed within PSTS50. Construction activities shall be carried out in accordance with the provisions of the Contractor’s Quality System which shall comply with the requirements of AS/NZS ISO 9001.

2.2 Hold Points, Witness Points and Milestones

a) The Hold and Witness Points particular to this Specification are listed in Table 3, Table 4 and Table 5 below. Refer General Specification (reference BC-PBA-GLRSP000-SPC-0001) for Hold Point, Witness Point and Milestone definitions and requirements. b) The Contractor shall not proceed beyond a Hold Point until the Hold Point has been

released by the person nominated in Table 3. The Contractor shall notify the relevant person when a Hold Point will be reached so that they can review and/or witness any work process, record or test being undertaken by the Contractor and thus expedite the release of that Hold Point.

Table 3 – Hold Points

Specification Clause Hold Point Details For Release By

All relevant Hold Points outlined in the Specifications and Project Deed including the hold points referred to in the QDMR Project Specific Technical Standards (PSTS) as described in Annexure 10 Part 1

IV

Hold Points as the Contractor deems necessary to meet its obligations under the Deed.

Contractor

4.3 Approval of shotcrete mix designs and mix trials (pre-construction tests) including the proposed curing regime

Construction Certifier

6.2 Certification of nozzlemen Contractor

8 Repair of shotcrete Construction Certifier

9 Remedial works to non-conforming shotcrete Construction Certifier c) The Contractor shall provide the person nominated in Table 4 reasonable notice

(minimum 24 hours or as otherwise specified) of all Witness Points so that inspection may be made of the following:

Table 4 – Witness Points

Specification Clause

Witness Point Details For Release By

Witness Points as the Independent Verifier deems necessary to meet its obligations under the Deed.

IV

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Specification Clause

Witness Point Details For Release By

necessary to meet its obligations under the Deed.

4.1/4.3 Trial Mixes / Field Trials Construction Certifier

5 Surface preparation complete (rock, concrete or waterproofing)

Construction Certifier

6.5 Final surface within tolerance Construction Certifier

d) The Contractor shall submit at the time nominated in Table 5, documentary evidence of Milestones to the Construction Certifier for approval of materials and workmanship as specified throughout the Specification.

Table 5 – Milestones

Specification Clause Milestone Details Timing

4.1 Construction Method Statement 30 days prior to

commencement of work 4.3 Submit proposed shotcrete mix designs 30 days prior to

commencement of work

4.3 Submit results of field trials 30 days prior to

commencement of work

2.3 Work Method Statements

Work Method Statements which are required to be submitted by the Contractor to the Construction Certifier in accordance with the quality system requirements of the Contract are listed below in Table 6.

Table 6 – Work Method Statements

Specification Clause Work Method Statements

4.1 Construction Method Statement for Tunnel Shotcrete Placement

2.4 Testing Frequency

The minimum testing frequency for work covered by this Specification is specified in Clause 7.

2.5 QDMR Registered Suppliers and Products

The use of QDMR registered suppliers and products for the construction of the project works are required for the items listed in Table 7.

Table 7 – Items Requiring Use of QDMR Registered Suppliers and Products

Specification Clause Category of Work

3.4 Cement Supply

3.5.1 Fly Ash

3.5.2 Silica Fume

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3 Shotcrete Materials

3.1 General

Materials for shotcrete as a minimum must conform to the requirements of this Clause of the Specification.

3.2 Shotcrete Types

The following shotcrete mixes are specified for this project:

a) Shotcrete Type S1: Steel fibre reinforced shotcrete for temporary support of

excavations. The characteristic cylinder strength of Shotcrete Type S1 at 28 days is 40 MPa.

b) Shotcrete Type S2: Steel mesh reinforced shotcrete for temporary support of excavations. The characteristic cylinder strength of Shotcrete Type S2 at 28 days is 40 MPa.

c) Shotcrete Type S3: Unreinforced shotcrete for temporary support of excavations. The characteristic cylinder strength of Shotcrete Type S3 at 28 days is 40 MPa.

d) Shotcrete Type S4: Un-reinforced shotcrete for infilling voids and smoothing of surfaces. The characteristic cylinder strength of Shotcrete Type S4 at 28 days is 25 MPa.

e) Shotcrete Type P1: Steel fibre reinforced shotcrete for permanent support of excavations. The characteristic cylinder strength of Shotcrete Type P1 at 28 days is 40 MPa.

f) Shotcrete Type P2: Steel mesh reinforced shotcrete for permanent support of excavations. The characteristic cylinder strength of Shotcrete Type P2 at 28 days is 40 MPa.

g) Shotcrete Type P3: Plain Shotcrete shall have monofilament polypropylene fibres in accordance with Section 3.9. The characteristic cylinder strength of Shotcrete Type P3 at 28 days is 40 MPa.

3.3 Water

a) Water incorporated into shotcrete shall be potable, free from contaminants harmful to concrete or reinforcement and have electrical conductivity not exceeding 1000 micro-siemens/metre.

b) Water to be used in the manufacture of shotcrete for the Temporary and Permanent Works shall be of an acceptable quality as defined in Clause 2.4 of AS 1379.

c) Water used for curing, testing water tightness or for other purposes where it may come in contact with shotcrete, shall be potable, clean and free from oil and suspended matter, and shall otherwise comply with the requirements of Clause 2.4 of AS 1379.

3.4 Cement

a) Cement shall be Type GB or GP in accordance with AS 3972.

b) All blended cement shall contain not more than 15% Fly Ash. The final blend shall be nominated by the Supplier or selected during field trials.

c) Cement older than three months from the date of dispatch from the manufacturer's holding silos shall not be used for the Temporary and Permanent Works.

d) All mixes shall contain a minimum mass of Portland cement equal to 55% of the total mass of cementitious material.

e) Test certificates for the cement showing suppliers’ details and demonstrating compliance with AS 3972 used shall be maintained for audit purposes. The test

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certificates shall cover the period from at least 12 months prior to commencement of the project. Testing of cement properties in accordance with AS 3972 shall be carried out at least monthly.

f) Cementitious products shall be supplied only by a QDMR Registered Cement Supplier.

3.5 Supplementary Cementitious Materials 3.5.1 Fly Ash

a) Supplementary cementitious materials Fly Ash and Slag shall comply with AS 3582 Parts 1 and 2 respectively and shall be a QDMR registered fly ash or slag, with the following modifications:

i. The amount of fly ash retained when wet sieved on a 45 micron sieve shall not exceed 15% by weight.

ii. Loss on ignition to be not more than 4% by weight.

iii. Specific gravity shall not vary by more than 5%. The uniformity of specific gravity shall be determined in accordance with Section 17 of ASTM C311.

3.5.2 Microsilica (Silica Fume)

a) Supplementary cementitious material Silica Fume shall comply with AS 3582 Part 3. Silica fume is a latent hydraulic binder which shall comply with the following

requirements:

I. Silica Fume/Dry Powder

i. Bulk density not exceeding 650kg/m3 ii. Silica content shall be not less than 85%

iii. Carbon content of silica fume shall be less than 5% iv. Particle size shall be between 0.1 and 0.2 microns

v. Fineness: specific surface area shall not be less than 15,000m2/kg vi. Relative Strength >95% after 28 days. Testing shall be in accordance with

AS3583.6

vii. Moisture content <3%.

II. Silica Fume/Water Slurry

i. pH shall be 5.5 ± 1.0

ii. Water content shall be 50% ± 2%

iii. Relative density shall be between 1.3 and 1.4.

b) Testing to establish compliance with (I) and (II) above shall be carried out once prior to work commencing and repeated annually during production for each supplier.

c) Silica fume/water slurry shall be regularly agitated by circulation pumps prior to use. d) The compatibility of silica fume and liquid admixtures shall be established by either:

i. Verification of existing test data, or

ii. Carrying out appropriate accelerated testing procedures

e) The Contractor shall maintain details of silica fume used in shotcrete for audit purposes.

3.6 Aggregates

a) In addition to the requirements of this Specification, aggregates for shotcrete shall be supplied from a quarry which holds QDMR certification (which shall be correct at the date of supply) and comply with AS 2758.1 as indicated below:

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i. The nominal maximum particle size shall be 10mm unless approved otherwise by the Construction Certifier.

ii. The Los Angeles coefficient shall be determined in accordance with sub clause 10.2 of AS 2758.1

iii. The magnesium sulphate soundness value determined in accordance with BS EN 1367-2 shall not exceed 18.

iv. The water absorption of the aggregate determined in accordance with AS 1141.6 shall not exceed 2%.

v. For aggregates comprising volcanic breccia, mudstone, shale, sandstone, weathered or altered rocks the drying shrinkage of the aggregate determined in accordance with AS 2758.1 shall not exceed 0.075%.

vi. The fines content less than 75 micron determined in accordance with AS 1141.12 shall not exceed 2%.

vii. The aggregate shall be tested for reactivity with the cementitious materials and admixtures (including accelerators) using the ASTM C1260-01 accelerated mortar bar method.

viii. Single size aggregates shall be combined in the proportions determined during the field trials. The individual fractions shall be stored separately.

b) Coarse and fine aggregates shall be free from earth, clay loam and soft clayey, shaley or decomposed stone, organic matter, friable particles and other impurities and shall be hard and dense. The grading shall be within the acceptable range according to the grading given in Table 8 below for wet mix shotcrete.

c) The grading and moisture content of the individual fractions of the aggregate shall be checked and recorded at least weekly.

d) The Contractor shall maintain for audit purposes details of aggregates and aggregate sources for shotcrete, including testing and properties of the aggregates.

e) The following aggregates have been tested and confirmed as suitable for use with polypropylene fibres for permanent shotcrete requiring resistance to fire:

• Bromelton North Olivine Basalt, • Beenleigh Meta-Greywacke,

• Petrie Greenstone

• Narangba Hornfelsed Greenstone.

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Table 8 – Aggregate Grading for Shotcrete

Sieve Size Percent Passing by Weight

S1, S2, S3, P1, P2 and P3 S4 9.5 mm 90 – 100 -6.70 mm 80 – 90 90 – 100 4.75 mm 70 – 85 75 – 90 2.36 mm 50 – 70 50 – 75 1.18 mm 35 – 55 35 – 55 600 μm 20 – 40 20 – 40 300 μm 8 – 20 8 – 20 150 μm 2 – 10 2 – 10 75 μm 0 – 2 0 – 2

3.7 Alkali-Aggregate Reaction (AAR)

a) Aggregates intended for use in shotcrete shall not react with alkalis in the concrete that may result in excessive expansion. The aggregate supplier must provide documentation of the potential reactivity of the aggregate in accordance with PSTS70 clause 11.1. The proposed concrete mixes shall meet the innocuous classification of QDMR Test Method Q458.

3.8 Admixtures 3.8.1 General

b) Admixtures for the purposes of this Specification shall not be used without the approval of the Construction Certifier.

c) Admixtures shall conform to the requirements of AS1478 and shall be a QDMR registered admixture.

d) Admixtures to the sprayed concrete mix shall be stated in the Method Statement. The performance of the modified mix shall be demonstrated by site trials prior to that mix being used in the Works.

e) All admixtures for shotcrete shall be sourced from a single manufacturer or supplier where possible to ensure compatibility of admixtures for use in the shotcrete. Where admixtures are sourced from different suppliers, evidence shall be obtained to demonstrate the compatibility of the admixtures. Compatibility of all admixtures with each other and with all other sprayed concrete constituents shall be verified during site trials.

f) The Contractor shall obtain sufficient documentation to support the use of all admixtures prior to commencement of field trials. The documentation shall include the

manufacturer’s product data and details of the equipment and method for controlling the addition of admixtures to the shotcrete.

g) Confirmation of the following requirements for all admixtures shall be obtained by the Contractor from the manufacturer prior to use in the tunnels and shafts:

i. Confirmation that admixtures are free of chlorides

ii. Arrangements for ensuring the consistency of supply and delivery of admixtures to the batching plant

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iii. Variations in the characteristic values of the properties of each admixture iv. Conditions for storage and handling of admixtures

v. Confirmation of the stability of admixtures with the mix water

vi. Results of testing as required by this Specification for each type of admixture vii. Confirmation that the additives are safe to use in a tunnel environment and any

safety precautions that are to be taken

3.8.2 Accelerators

a) Accelerators are admixtures. Only liquid accelerators shall be used. b) Sodium Silicate (Waterglass) shall not be used.

c) Only the minimum quantity of accelerator necessary shall be permitted in normal shotcreting operations. The quantity shall be determined by field trials, subject to the maximum dosages specified in Table 9:

Table 9 – Maximum Dosages of Accelerator

Shotcrete Type By weight of cementitious material

S1 8% S2 8% S3 8% S4 8% P1 5% P2 5% P3 5% d) Testing of accelerators in accordance with this Specification with regard to acceleration

of setting, early strength, and decrease of strength at a later age (28 and 90 days), shall take place in due time before commencement of shotcrete application.

e) The Contractor shall test selected types of accelerators over a range of ±2% for 5.0% or 8.0% dosages (See Table 9) but shall not exceed the manufacturer’s recommended dosage to ensure the short and long term strength is not impaired and meets the specified requirements. Laboratory testing of the selected type(s) of accelerator shall be carried out in accordance with this Specification at dosages of 5.0% and 8.0% for non-caustic, alkali free accelerators by weight of cementitious material in the base concrete, or similar dosages as recommended by the manufacturer, to establish the variability of the above properties with dosage. Accelerators showing excessive variability with dosage will not be permitted.

f) Accelerators shall be selected such that, at the dosage chosen for use, the decrease in strength of any Shotcrete Type at an age of 28 days, compared with the base concrete without any accelerators, shall not exceed 25%. Also, there shall be no further

reduction in strength of the shotcrete mix between 28 and 90 days. Compliance with this clause shall be demonstrated by testing at a frequency as deemed necessary.

3.8.3 Plasticisers and Retarders

a) Plasticisers and retarders are admixtures and shall comply with AS 1478 and may be used in Shotcrete Types S1, S2, S3, S4, P1, P2 and P3 subject to the approval of the Construction Certifier.

b) Plasticisers and retarders may be used to reduce the quantity of the mixing water and to improve the pumpability of the shotcrete. The effects and optimum dosages of

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plasticisers and retarders shall be determined during development of the mix design and/or by field trials in accordance with this Specification.

c) Plasticisers and retarders shall not contain calcium chloride.

d) Compatibility of plasticisers and retarders with cements, latent hydraulic binders and accelerators shall be verified by observation during development of the mix design and/or in the field trials.

e) Plasticisers and retarders shall be used in accordance with the manufacturer’s instructions.

3.8.4 Hydration Control Admixtures

a) Hydration control admixtures may be used with Shotcrete Types S1, S2, S3, P1, P2 and P3 in accordance with this Specification and subject to the approval of the Construction Certifier. Hydration control admixtures used with accelerator in Shotcrete Type S1, S2, S3, S4, P1, P2 and P3 shall not cause a decrease in strength with age.

b) Hydration control admixtures may be used to control the hydration of the mix as appropriate to expedite construction of the Temporary and Permanent Works. The effects and optimum dosages of hydration control admixtures shall be determined by field trials in accordance with this Specification.

c) Hydration control admixtures that delay the setting process by greater than 10 hours for Shotcrete Type S1, S2, S3, S4, P1, P2 and P3 shall not be used. Proposals to use hydration control admixtures for longer periods may require additional field trials and/or testing as specified by the Construction Certifier.

d) Compatibility of hydration control admixtures with cements, latent hydraulic binders and accelerators shall be verified by observation in the field trials.

e) Hydration control admixtures shall be used in accordance with the manufacturer's instructions.

3.9 Fibres 3.9.1 General

a) Fibres may be collated with fast-acting water-soluble glue, or may be uncollated individual fibres. Water-soluble glue or other additives used to collate fibres shall be compatible with other shotcrete components.

b) Fibres shall be stored in dry sealed containers until ready for use and shall be free from corrosion, oil, grease, chlorides and deleterious materials which may reduce the efficiency of mixing or spraying processes, or which may reduce the bond between the fibres and the shotcrete. Containers of fibres shall be stored in areas protected from the weather and extremes of heat as per the manufacturer’s instructions.

c) Fibre type shall be selected on the basis of compliance with this Specification and on suitability and ease of use in the batching, mixing and shotcreting processes proposed, as demonstrated by field trials. Fibres which tend to form fibre balls during batching and mixing shall not be used.

3.9.2 Steel Fibres

a) Steel fibre shall be deformed steel fibre Type 1, 2 or 3 in accordance with ASTM A820 except that Type 1 fibre may be either circular or rectangular in section. Fibres shall be produced from milled steel or cold drawn wire and shall be ungalvanised.

b) Steel fibres shall have an aspect ratio in the range of 30 to 150. Tolerances shall be in accordance with ASTM A820.

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GL - Supplementary Specification - Tunnel - Shotcrete Lining GLTSP102 3.9.3 Synthetic Fibres (Structural)

a) Synthetic fibres shall be of the structural macro-synthetic type of fibre in accordance with BS EN 14889-2 and of greater than 0.3mm diameter. The fibre shall have a textured surface and be produced from polyolefin or a similar base resin material. .

3.9.4 Synthetic Fibres (Fire)

a) Synthetic Fibre may be used in Shotcrete Type P1, P2 or P3 to achieve the specified design requirements for the fire load case.

b) Micro-synthetic fibres shall be 18-32 micron monofilament PP fibres specifically manufactured for use as a concrete additive and so certified by the manufacturer, and containing no reprocessed olefin materials.

c) Alternative monofilament PP fibre dimensions may be proposed provided they have test data to demonstrate they have equivalent fire performance criteria as the 18-32 micron fibres.

d) The required dosage and effectiveness of fibres in reducing concrete spalling due to exposure to fire shall be assessed by the Concrete Fire Testing Specification (reference BC-PBA-GLSSP414-SPC-0001).

3.10 Soluble Salts (permanent shotcrete only)

a) The chloride ion content of the hardened shotcrete must be tested in accordance with AS1012.20. A representative sample of at least 20 grams of crushed and ground shotcrete shall be used, with the titrating solution being 0.01 to 0.02N. For the test, use the Volhard method calibrated using a concrete with known chloride content.

b) The mass of acid-soluble chloride ion per unit volume of permanent shotcrete as placed must not exceed the values given in Table 10.

c) The sulphate content of shotcrete, determined by calculation and expressed as the percentage by mass of acid-soluble SO3 to cement, must not be greater than 4.0%. Table 10 – Maximum Values of Acid-Soluble Chloride-Ion Content in Shotcrete

Exposure * Classification

Maximum acid-soluble chloride ion content (kg/m) Fibre Reinforced Concrete or Conventional Reinforced Concrete

A 0.8 B1 0.8 B2 0.8

Note: Chloride ion content may be expressed in percentage weight of oven dried concrete. (0.1 kg/m3 ion content is approximately equivalent to 0.004% by weight of oven dried concrete). *For information on exposure classifications see AS 5100.5.

4 Shotcrete Requirements

4.1 Construction Method Statements

a) A Construction Method Statement for the tunnel shotcrete lining works shall be prepared prior to commencing any work. The method statement is to be submitted for review to the Construction Certifier at least 30 days prior to the commencement of temporary or permanent shotcreting works Milestone. The Construction Method Statement shall contain, as a minimum, full details of the following where appropriate: i. Methods of working

ii. References to Safety Plan and Quality Assurance procedures iii. Names of responsible persons

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iv. Proposed methods for Surface Preparation

v. Proposed methods for use of steel reinforcement and other embedments where applicable

vi. Proposed methods and equipment for mixing, conveying and applying shotcrete vii. Details of procedures for monitoring of shotcrete thickness, including spacing of depth indicators (if applicable) and details of how the profile is to be maintained. viii. Repair procedures, including proposed mix designs for core hole repair

4.2 Mix

a) Mix designs shall comply with the requirements shown in Table 11. Witness Point. Table 11 – Particular Mix Requirements

Parameter Shotcrete Type

S1 S2 S3 S4 P1 P2 P3

Steel Fibre

- minimum tensile strength (MPa) - minimum length (mm) - maximum length (mm) - minimum content (kg/m3) 900 25 50 30 N/A N/A N/A N/A 900 25 50 30 N/A N/A N/A N/A

Cementitious Material Type GP or GB** with microsilica

Minimum Cementitious Content

(kg/m³) 400

Maximum Water * : Cementitious

Content Ratio 0.45

Accelerator Type Non-caustic, alkali free

Silica Fume Content _5-10%

(4-8% when used with Type GP or GB)

* Water shall include the liquid content of liquid admixtures

** Fly ash content not to exceed 15% by weight. Care should be taken in the choice of cementitious materials to ensure that sufficient lime is available for reaction with the silica fume.

b) Shotcrete shall be applied by the wet mix process and be capable of being applied in layers up to 150 mm in thickness with good adhesion to the ground or previous layers of shotcrete without sagging or slumping.

c) Shotcrete shall be dense and homogeneous without segregation of aggregate and/or fibre or other visible imperfections.

4.3 Acceptance Testing and Field Trials

a) The purpose of the field trials is to check the suitability of the proposed mix design, materials, plant, the work methods and the competence of the shotcrete operators. Sprayed panels shall be used to verify the following design properties:

i. Compressive strength;

ii. Density; iii. Fibre content;

iv. Shrinkage (for permanent shotcrete only); v. Permeability (for permanent shotcrete only);

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vi. Flexural strength (for permanent shotcrete only); and vii. Flexural Toughness.

b) Field trials shall be started sufficiently early to ensure that the required shotcrete mixes are developed and all trials completed satisfactorily by the time shotcreting of each Shotcrete Type commences in the Temporary and Permanent Works. Shotcreting of any Shotcrete Type shall not commence until the relevant trials have been completed, and the results of the field trials and acceptance testing submitted to the Construction Certifier for approval at least 30 days prior to the commencement of Shotcreting Hold Point 1 Witness Point Milestone.

c) The field trials shall employ the types of equipment which will be used in the Temporary and Permanent Works and the constituent materials shall be fully representative of those to be used in the Temporary and Permanent Works.

d) Each field trial shall be a witness point with a notice period of three (3) days.

e) As an alternative to field trials the Contractor may adopt a proven shotcrete mix design with a test history of at least 12 months that demonstrates compliance with the

requirements of this Specification to be submitted for approval Milestone.

f) If field trials are required, testing for field trials shall be in accordance with Table 12. Table 12 – Testing Methods – Field Trials

Test Method

Compressive Strength (cast sample) AS 1012.8 and AS 1012.9

Compressive Strength (cored sample) AS 1012.14

Flexural Toughness (Round Panels – SFRC Only) ASTM C1550-03a

Fibre (SFRC only) This Specification

4.4 Sprayed Concrete Trials

a) From the field trial mix an experienced nozzleman shall prepare sufficient test panels. Panels for coring shall be at least 1000 x 1000mm in size and shall be 200mm thick. The panels shall be prepared by shotcreting into rigidly supported vertical moulds. Moulds shall be constructed of steel or other non-water absorbing rigid materials. The upper and lower edges of the mould shall have parallel sides splayed outwards at 45 degrees to the back face to prevent the entrapment of rebound. The vertical edges of the mould shall have parallel sides at 90 degrees to the back face to facilitate coring perpendicular to the spray direction. Round panels for flexural toughness testing shall be 800 ±10mm diameter and 75 ±15mm thick, and prepared by shotcreting into rigidly supported vertical moulds in accordance with ASTM C1550-03a. In all cases, the shotcrete in panels shall adhere well to the backform, be properly compacted and exhibit no sagging.

b) The target slump(s) shall be confirmed by trial mixes with and without superplasticisers. The pre production and production tests on sprayed shotcrete shall comply with the short and long term strengths specified in Table 13 for field tests and production tests (cores). For sprayed concrete the target slump shall be;

• Without superplasticiser: 80 to 120mm • With superplasticiser: 80 to 150mm

c) All panels shall be protected immediately against moisture loss using the same method to be used in construction, shall not be moved for 18 hours after spraying, and shall be stored without disturbance until the time of coring, sawing, or testing. Cores for 1, 7, 28 and 90 day compressive strength tests shall be obtained from the panels at 22hours.

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The cores for 7, 28 and 90 day strength tests shall be stored in water in accordance with AS 1012. Round panels for flexural toughness testing shall be stored in water in accordance with AS 1012.

d) Cylindrical test specimens shall be cored from each test panel and tested as listed below. Drilling of test specimens shall be in accordance with AS 1012.14. Drilling of cores shall be located to avoid areas of possible rebound. No two cores to be tested at any given age shall come from the same panel. Cores to be tested at different ages (i.e. 1, 7 and/or 28 days) may come from the same panel. For each test at least one spare specimen shall be provided. The testing requirements and core dimensions shall be: i. Compressive strength in spray direction after 1, 28 and 90 days on 4 cores each.

The prepared test cores shall be 75mm diameter and 150mm long (minimum). ii. Compressive strength perpendicular to spray direction after 1, 7, 28 and 90 days on

4 cores each. The prepared test cores, to be taken from different panels, shall be 75 mm diameter and 150 mm long (minimum).

e) Each cored cylinder or round determinate panel shall be marked with an appropriate reference mark and the date and time of shotcreting.

f) Steel fibres used shall have a minimum tensile strength of at least 900 MPa

g) Setting times shall be observed during the field trials in accordance with BS EN 196-3. h) Optimum fibre content shall be determined dependent on ease of use in the batching,

mixing, and shotcreting processes proposed, and from the results of the tests to determine flexural toughness by the testing of round determinate panels.

i) The compressive strength of shotcrete cores from test panels shall be acceptable if the compressive strength results both for samples with their axes parallel to the direction of spraying and for samples with their axes perpendicular to the direction of spraying, comply with the minimum performance requirements set out in this Specification. One test result shall consist of the mean of three core strengths (a spare specimen shall be taken but not tested). Seven day results shall be used for indicative purposes only. The compressive strength of cores in steel fibre reinforced or plain shotcrete shall be deemed to be the in situ cylinder strength provided that the specified requirements are met in terms of core diameter and height: diameter ratio.

j) A minimum of three successful Round Panels tests that meet the specification in Table 13 are required for each shotcrete mix.

k) The Contractor shall carry out such other tests and trials during the period of the field trials as may be necessary, to confirm that proposed mixes and methods meet the minimum performance requirements and particular mix requirements of this Specification.

l) The field trials shall be repeated if the source or qualities of any of the materials or the mix proportions are required to be changed during the course of the Temporary and Permanent Works.

m) For permanent quality shotcrete applications the durability of the sprayed concrete mix shall be established by water permeability tests carried out on additional cores taken from the panels

n) The Contractor shall provide 1,7,28 & 90 day strength verses time curves for cores taken directly from the tunnel lining together with early strength results (less than 1 day) for beam end test verses needle penetrometer tests

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GL - Supplementary Specification - Tunnel - Shotcrete Lining GLTSP102 4.5 Submission Details

a) The Contractor shall submit details of each shotcrete mix design for approval to the Construction Certifier at least 30 days prior to the commencement of shotcreting works. The submission shall include, as a minimum, the following information:

I. Mix Design

i. The name of the concrete supplier and the proposed methods and degree of quality control

ii. Types and proportion by mass of various materials comprising the mix, including chemical admixtures and supplementary cementing materials iii. A copy of the Quarry Assessment Certificate for each material source iv. Target strength

v. Trial mix water/cement ratio and corresponding nominated water/cement ratio. vi. Slump of the trial mix and corresponding nominated slump

II. Trial Mix

i. Number and sizes of test panels ii. Base mix used in each test panel

iii. Type and dosages of nozzle-added admixtures iv. Required and actual thickness

v. Description of finished product

vi. The degree of control required to achieve uniform shotcrete without excessive rebound, sloughing, partial or total collapsing during shotcreting.

b) This constitutes a hold point for each different shotcrete mix used in the works covered by this Specification.

4.6 Performance

The performance requirements are shown in the Table 13. Table 13 – Minimum Performance Requirements for Shotcrete

Parameter Test Method or

Clause No

Shotcrete Type

S1 S2 S3 S4 P1 P2 P3 Min Mean Insitu Cylinder

Strength [MPa] +++ Field trials and Production Tests (Core) at 1 day + at 7 days* at 28 days at 90 days ++ AS 1012.14 (cored samples) 8MPa 20MPa 32MPa 32MPa N/A N/A 25MPa 8MPa 20MPa 32MPa 32MPa Field trials and Production Tests (Cylinder) at 1 day + at 7 days* at 28 days at 90 days ++ AS 1012.8.1 AS1012.9 (cylinder samples) 8MPa 25MPa 40MPa 40MPa N/A N/A 25MPa 8MPa 25MPa 40MPa 40MPa

Max In-situ Cylinder Strength As above 70MPa(1)

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Determinate Panels) at 1.0mm deflection at 5.0mm deflection at 20mm deflection at 40mm deflection ASTM C1550-03a 12 J 62 J 211J 282J N/A 12 J 62 J 211J 282 J N/A Dry Density

[All tests at 28 days] AS 1012.8 2150 to 2400kg/m³

Boiled Absorption (max. %) [All tests at 7 days] (for permanent shotcrete only)

AS 1012.21 8% max

Apparent Volume of Permeable Voids (max. %) [All tests at 7 days] (for permanent shotcrete only)

AS 1012.21 17% max

Early Age Compressive Strength

Beam End Test

(**) 1.0MPa before personnel re-entry into heading. Shrinkage Strain (for

permanent shotcrete only)

AS1012.13 N/A 850 microstrain

after 8 weeks drying Permeability (for permanent

shotcrete only) DIN1048 Part 5 N/A 25mm maximum penetration Fire Performance of P3 shotcrete

Permanent shotcrete with 2kg/m3 dosage of polypropylene fibres made from aggregates listed in Section 3.6. A lower dosage may be

acceptable if fire tests using the same concrete mix, fibres and aggregates meet the fire performance requirements.

* Tests used for indicative purposes only.

** Refer to section 11.4.4 Concrete Institute of Australia, Recommended Practice – Shotcreting in

Australia

+ Compressive Test at 1 day may be stopped depending on compliance and as approves by the Construction Certifier.

++ Compressive Tests at 90 days are only required if hydration control admixtures are included in the shotcrete mix.

+++ The required minimum values of mean in situ cylinder strength require that testing shall be on drilled cores in accordance with this Specification, i.e. 2:1 height: diameter ratio. No other height: diameter ratio shall be used.

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Maximum Strength is specified to avoid brittle failure of shotcrete. Exceptions may be approved on a case by case basis through the RFI process.

5 Surface Preparation for Shotcrete Application

5.1 Preparation of Rock Surfaces

Before the application of sprayed concrete, the excavated surfaces shall be scaled by mechanical hydraulic hammers or high-pressure hydro scaling to remove loose rock or scats or shall be cleaned with compressed air and, as far as the local conditions permit, with an air-water mixture as necessary to remove all material which may prevent proper

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adhesion of the sprayed concrete to the excavated surface. The surface to receive shotcrete shall be damp and without free water prior to application of sprayed concrete.

Action shall be taken as necessary to control ground water and prevent it adversely affecting the sprayed concrete lining. Water inflows which might cause deterioration of the concrete, or prevent adherence, shall be diverted by channels, chases, pipes or other appropriate means to the invert or to the ground water drainage system.

Where necessary, pressure relief holes shall be provided through the primary lining to ensure that no hydrostatic pressure develops behind the lining.

5.2 Preparation of Shotcrete / Concrete Surfaces

Existing shotcrete/concrete surfaces to be shotcreted shall be cleaned of any spalled, cracked, deteriorated, loose, unsound and/or chemically contaminated shotcrete/concrete until a sound and uncontaminated shotcrete/concrete is reached. Water blasting, chipping, scabbling or other mechanical means shall be used to remove any contaminated shotcrete/ concrete Witness Point.

Where reinforcement is exposed, it should be free from loose rust, scale or other deleterious matter likely to effect durability and bonding.

Where shotcrete is to be placed against a smooth concrete surface, the surface shall be roughened by mechanical methods or by water blasting.

After the above preparation is carried out, the concrete surface shall be pre-wetted prior to the application of shotcrete and any excess water shall be removed.

5.3 Preparation for Installation of Waterproof Membrane

a) Prior to fixing either a separation or waterproof membrane, a survey of the initial shotcrete lining shall be performed to confirm the correct profile of the lining. Any remedial measures required to correct out of tolerance profiles shall be undertaken in accordance with approved Method Statements as required by the Waterproofing Supervisor in accordance with specification (reference BC-PBA-GLTSP107-SPC -0001) b) Where shotcrete is to be applied to a substrate comprising either a pre-formed sheet

membrane or a spray-on waterproof membrane the surface shall be prepared strictly in accordance with the manufacturer’s recommendations and the relevant work method statement. On no account shall SFRS be sprayed directly onto sheet membrane, unless the membrane manufacturer can provide a guarantee that this will not damage the membrane.

5.3.1 Smoothing Shotcrete (Type S4)

a) Smoothing shotcrete shall conform to the general requirements of PSTS04 with respect to material and workmanship.

b) The tunnel shotcrete smoothing layer shall be in accordance with Design Drawings and generally as follows:

i. Shotcrete surfaces onto which a waterproof membrane is to be applied shall be prepared by the addition of a shotcrete smoothing layer to remove local peaks and infill hollows.

ii. Surfaces on which waterproofing systems will be installed shall be clean, free from loose aggregate, sharp protrusions, projecting tying wire, release agents and other substances which are likely to damage or affect the waterproofing system.

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iv. Large circumferential irregularities shall not exceed 200 mm when measure from a 1.0 m curved edge held against the tunnel circumference.

v. Any curvature or irregularity shall have a radius greater than 200 mm.

vi. The shotcrete shall be cured for at least 24 hours prior to membrane application. vii. Steel elements, such as reinforcement bars, steel fibres, steel girders and the

heads of rock bolts (as far as not used to hold inner lining structures) shall be covered with at least 20mm of shotcrete.

viii. Running water ingress shall be plugged prior to the final lining. Heavy water ingress can be collected into half-pipes (or flexi-drain or strip-drains or similar), mounted by nailing and led into the permanent drainage system. The mounted half-pipe should be covered with at least 20mm of shotcrete prior to the initial temporary works shotcrete lining installation.

ix. Where water is found to be penetrating through the shotcrete lining at a rate that may adversely affect the installation of membrane, the water shall be collected by means of hoses and drained to the tunnel invert. The drainage shall be maintained during the membrane installation process so that no water pressure can develop behind the membrane.

x. Inspection and acceptance shall be required in accordance with the approved Contractor’s construction work method statement.

xi. The shotcrete smoothing layer shall be completed using a maximum aggregate size of 4mm unless it can be demonstrated that a coarser aggregate can achieve a surface compatible with the membrane manufacturer’s recommendations. Shotcrete surface shall be at least 28 days old prior to the application of spray applied membranes.

6 Application of Shotcrete and Curing

6.1 Equipment

a) Only wet mix process equipment shall be used for Shotcrete Types, S1, S2, S3, S4, P1, P2 and P3. Equipment for the wet mix process shall be set up according to the

recommendations of the manufacturer. Pumping equipment shall ensure the continuous conveyance of shotcrete at a steady and quantifiable rate with minimal pulsation. The equipment shall allow for air and water in any combination to be available for

preparation of surfaces and/or cleaning of finished work in accordance with this Specification.

b) All equipment used for batching and mixing of materials, and the transport and application of all types of shotcrete shall be of suitable design and shall be maintained in proper working order for the duration of excavation and lining works. The shotcrete gun and ancillary equipment shall be of an adequate capacity for the volumes to be applied, and shall be manufactured from suitable materials compatible with the

proposed accelerators and additives. A stand-by shotcrete system of plant and ancillary equipment shall be available for the duration of excavation operations to ensure

shotcrete is available at all times to stabilise all exposed excavation faces. Air for the equipment is to be clean, dry and oil free and to be provided at the equipment at not less than the operating pressure and volume rates specified by the manufacturer. c) Shotcreting equipment shall be capable of feeding materials at a regular rate and

ejecting shotcrete from the nozzle at velocities that will allow adherence of the materials to the surface being shotcreted with a minimum of rebound and maximum adhesion and density.

Specification - Tunnel Shotcrete Lining

Thiess John Holland

Joint Venture

Airport Link | Northern

Busway | EWAG

GL - Supplementary

Specification - Tunnel -

Shotcrete Lining

GLTSP102

Document ref

BC-PBA-GLTSP102-SPC-0001-1-03

26 May 2010

DCN: 00047

IFA / AFC

Thiess John Holland

Joint Venture

Airport Link | Northern

Busway | EWAG

GL - Supplementary

Specification - Tunnel -

Shotcrete Lining

GLTSP102

Document Verification

Contents

Tables

Appendices

1

General

2

Quality System Requirements

3

Shotcrete Materials

4

Shotcrete Requirements

5

Surface Preparation for Shotcrete Application

6

Application of Shotcrete and Curing