08 Shotcrete Quality Control & Testing for an Underground Mine in Canada

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Shotcrete Quality Control and Testing for

an Underground Mine in Canada

By

Dudley R. (Rusty) Morgan

and

Mazin Ezzet

AMEC Earth & Environmental,

a division of AMEC Americas Limited

SHOTCRETE FOR AFRICA CONFERENCE

Misty Hills Conference Centre

South Africa

2-3 March, 2009


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Subject of Presentation

General Introduction

Standards and Codes Shotcrete Materials Requirements

Cementing Materials

Aggregates

Mixing Water

Chemical Admixtures

Shotcrete Performance Requirements


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Subject of Presentation (continued)

Quality Control Testing

Aggregates Batching and Supply (Plastic Shotcrete)

Hardened Shotcrete


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Shotcrete Quality Control Organizational Chart


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New Underground Gold Mine in British Columbia


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Portal at Decline into Underground Mine


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Mobile Mass Batcher Unit

Discharging into Ready-Mix Concrete Truck


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Remixer Unit for Hauling Shotcrete Down Decline


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Remixer Unit Discharging into

Shotcrete Pump at Back of Shotcrete Sprayer


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Remote Control Shotcrete Sprayer


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Manipulator Arm on

Remote Control Shotcrete Sprayer

Shooting ASTM C1550 Round Test Panels


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Ready for Shotcreting Underground


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Drilling Face for next Round of Blasting

Note Shotcrete with Bolts and Plates


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Standards and Codes

American Concrete Institute (ACI)

American Society for Testing and Materials (ASTM)

Canadian Standards Association (CSA)

National Ready Mix Concrete Association (NRMCA)

Concrete Plant Manufacturers Bureau (CPMP)


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Standards and Codes

Standard Test Method for Obtaining and Testing Drilled Cores of

Shotcrete

ASTM C1604

Standard Specification for Mixing Water Used in Production of

Hydraulic Cement Concrete

ASTM C1602

Standard Specification for Flexural Toughness of Fibre Reinforced

Concrete (Using Centrally Loaded Round Panel)

ASTM C1550

Standard Specification for Materials for ShotcreteASTM C1436

Specification for Admixtures for ShotcreteASTM C1141

Standard Practice for Preparing and Testing Specimens from

Shotcrete Test Panels

ASTM C1140

Specification for Fibre Reinforced ConcreteASTM C1116

Standard Test Method for Specific Gravity, Absorption, and Voids

in Hardened Concrete

ASTM C642-82

Standard Test Methods for Chemical Analysis of Hydraulic

Cements

ASTM C114


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Standards and Codes (continued)

Cementitious Materials for Use in ConcreteCSA A3001-03

Methods of Test and Standard Practices for ConcreteCSA A23.2-04

Concrete Materials and Methods of Concrete ConstructionCSA A23.1-04

Canadian Standards Association (CSA)

Specifications for Materials Proportioning and Application of

Shotcrete

ACI 506.2-95

Guide to ShotcreteACI 506R-05

American Concrete Institute (ACI)


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Shotcrete Materials

Cementing Materials

Portland Cement: CSA Type GU

Fly Ash: CSA Type F or CI

Silica Fume: CSA Type SF

Other Cementing Materials

Natural Pozzolans

Calcined Metakaolins

Ground Granulated Blast Furnace Slag

Li it f D l t i S b t d


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Limits for Deleterious Substances and

Physical Properties of Aggregates

1216MgSO4 soundness lossA23.2-9A

50-Impact and abrasion lossA23.2-16A

6-Unconfined freeze-thaw testA23.2-29A

1720Micro-Deval testA23.2-23A

20-Flat and elongated particles

Procedure A, ratios 4:1

A23.2-13A

1.03.0Material finer than 80 mA23.2-5A

0.50.5Low-density granular materialsA23.2-4A

0.251Clay lumpsA23.2-3A

CoarseAggregateFine AggregateStandard RequirementsCSA TestMethod

Maximum Percentage by

Mass of Total Sample

Property


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Grading Limits for Fine Aggregate

0-380 m

2-10160 m

10-35315 m

25-65630 m

50-901.25 mm

80-1002.5 mm

95-1005 mm

10010 mm

FA1Sieve Size

Total Passing Sieve, Percentage by Mass


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Grading Limits for Coarse Aggregate

0-51.25 mm

0-102.5 mm

10-305 mm

85-10010 mm

10014 mm

Total Passing Sieve, Percentage by MassNominal Size of Aggregate


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Grading Limits for Combined Aggregates

0-380 m

2-10160 m

8-20315 m

20-35630 m

35-551.2550-702.5 mm

70-855 mm

90-10010 mm

10014 mm

Total passing sieve, percentage by massSieve Size


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Graph of ACI No. 1 & No. 2 Gradings

0

20

40

60

80

100

120

0.08 0.16 0.315 0.63 1.25 2.5 5 10 14

Metric Sieve Size

P

ercentPa

ssing

ACI Gradation 1 Limits

ACI Gradation 2 Limits

Combined % Passing


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Chemical Limits for Mixing Water

C160350,000Total solids by mass

C114600Alkalies as (Na2O + 0.658 K2O)

C1143000Sulphate as SO

C1141000Chloride as Cl

ASTM Test MethodLimitsMaximum Concentration

In Mixing Water, ppm


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Chemical Admixtures

Water Reducing Admixtures

Set Retarding or Hydration Controlling Admixtures

Air Entraining Admixtures

Set Accelerators Added at Nozzle


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Fibres

Steel Fibres:

ASTM C1116 Type I and ASTM A 820

Synthetic Fibres:

ASTM C1116 Type III


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Typical Shotcrete Performance Requirements

2 MPaMinimum early age compressive strengthbefore re-entry under shotcrete

Penetrometer as calibratedagainst beams tested as

equivalent cubes

*Minimum Joules energy at 40 mmdeflection in round panel test

ASTM C1550

9 %

18 %

Maximum values of boiled absorption

Maximum volume of permeable voids

ASTM C642

10MPa30 MPa

40 MPa

Minimum compressive strength of

shotcrete cores

1 Day7 Days

28 Days

ASTM C1604 & CSA A23.2

14C

2-5 %Air content as shotCSA A23.2 4C

10-30oCTemperature

(at discharge into shotcrete pump)

-

170 20 mmSlump

(at discharge into shotcrete pump)

CSA A23.2 5C

0.40Maximum water/cementing materials ratio-

Performance RequirementPropertyTest Method


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Fibre Reinforced Shotcrete Testing in North America

Steel fibre synthetic macro-fibre reinforced shotcrete in North

America has been tested to the following ASTM Standards:

ASTM C1018: Standard test method for flexural toughness andfirst-crack strength of fiber-reinforced concrete (using beam withthird point loading) first published 1984, withdrawn 2006

ASTM C1609: Standard test method for flexural performance offiber-reinforced concrete (using beam with third point loading)first published 2005

ASTM C1550: Standard test method for flexural toughness offiber reinforced concrete (using centrally loaded round panel)


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ASTM C1018 and ASTM C1609 Beam Test


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ASTM C1018 Load vs Deflection Curve

Test Results Include: First crack and ultimate flexural strengths (MPa)

Toughness Indices I5, I10, I20, etc

Residual Strength Factors R5,10, R10,20, etc.

Problems of reliability with this test method and withdrawn in 2006

Fibre Shotcrete Tests

Flexural Toughness Performance Levels


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Flexural Toughness Performance Levels

Morgan and Chen, 1995


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Fibre Shotcrete Beam Tests

ASTM C1609 Load vs Deflection Curve


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ASTM C1550 Round Panel Test


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ASTM C1550 Round Panel Test


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Technical Report


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Typical Shotcrete Mixture Design

1.0105Yield (m3) =2354Total

0.0202-2.0At Shot (%)

--2.5

Air Content:

At Pump (+/- 1.5%)

0.00669106.0Macro Synthetic Fibre

0.001210001.2Hydration Controlling Admixture, L

0.002510002.5High Water Reducing Admixture, L

0.18501000185Estimated Water, L

0.494526491310Fine Aggregate (SSD)

0.13852744380Coarse Aggregate (10-2.5mm, SSD)

0.0205220045Silica Fume0.13653150430Cement Type GU

Volume

[m3]

Density

[kg/m3]

Mass per m3 SSD

Agg [kg]Material


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Shotcrete Quality Control Certification and Testing

Aggregates

Batch Plant

Mixers

Plastic Shotcrete

Hardened Shotcrete


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Shotcrete Aggregates Testing Frequency

Each daySurface Moisture in Fine and Coarse AggregatesA23.2-11A

6 monthsRelative Density and Absorption of Coarse AggregateA23.2-12A

1 weekOrganic Impurities Colour TestA23.2-7A

6 monthsRelative Density and Absorption of Fine AggregatesA23.2-6A

Each deliverySieve Analysis of Fine and Coarse AggregatesA23.2-2A

1 yearAlkali Silica ReactivityA23.2-25A

1 yearPetrographic AnalysisA23.2-15

6 monthsMgSO4 Soundness LossA23.2-9A

6 monthsImpact and Abrasion LossA23.2-16A

6 monthsUnconfined Freeze-thaw TestA23.2-24A

6 monthsMicro-Deval TestA23.2-23A

6 monthsFlat and Elongated ParticlesA23.2-13A

1 weekMaterial Finer than 80 mA23.2-5A

6 monthsLow Density Granular MaterialsA23.2-4A

6 monthsClay LumpsA23.2-3A

Testing FrequencyPropertyCSA Test Method


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Shotcrete Batching and Supply Certification and Testing

Each batch of shotcrete

produced

Batch records with solid materials in

kg and liquids in L

NRMCA CPMB 100 M-07

Before use and every 6

months

Certification of ready mix concrete

truck mixers and remixer units

NRMCA CPMB 100 M-07

At start of project and every 2

years

Certification of ready mixed concrete

production facilities using truck mixing

NRMCA CPMB 100 M-07

Testing FrequencyTest ProcedureTest Method


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Plastic Shotcrete QC Testing

At start of project and with any

change in fibre type or dosage

Wash-out test to determine uniformity

of fibre distribution at discharge from

remixer unit

CSA A23.2-7C

Modified


change of mixture proportions

Air Content as-shot (without

accelerator)

CSA A23.2-7C

Modified


change in mixture proportions

Air content of plastic shotcrete at

discharge into remixer unit and at

shotcrete pump

CSA A23.2-7C


produced

Shotcrete and ambient temperatures

at discharge into remixer unit and at

shotcrete pump

At beginning of each shiftSlump at discharge into shotcretepump

CSA A23.2-5C


produced

Slump at discharge into remixer unitCSA A23.2-5C

Testing FrequencyTest ProcedureTest Method


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Hardened Shotcrete QC Testing

Two panels at 28 days for each

week of shotcrete production or

at any change in fibre type ordosage

Round panel test to 40 mm deflectionASTM C1550

Two panels at each of ages 7and 28 days at start of project

for one fibre type and dosage

Round panel test to 40mm deflectionASTM C1550

One heading per week for each

shotcrete robot used

Boiled absorption and volume of permeable

voids

ASTM C642

One heading per week for each

shotcrete robot and eachshotcrete crew used

Compressive strength of cores extracted

from shotcrete test panel at age 1 day (1core), 7 days (1 core) and 28 days (2 cores)

ASTM C1140

ASTM C1604

One heading per shiftEarly age compressive strength estimate

using penetrometer

Penetrometer


change in mixture proportions or

accelerator type or dosage

Early age compressive strength of beams as

equivalent cubes

Ref. 1

Testing FrequencyTest DescriptionTest Method

Q li A Pl


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Quality Assurance Plan

Shotcrete Quality Control

Shotcrete Materials Check List

Inspection and Test Plan (ITP)a) Materials

b) Batching and Supply

c) Hardened Shotcrete

Shotcrete Quality Audit

Non-conformance Report (NCR)

Opportunity for Improvement Report (OFI)

Corrective Action Report (CAR) Audit Report

C l i


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Conclusions

Production of quality shotcrete in an underground

environment requires:

Rigorous shotcrete specifications Implementation of a quality management plan

(follow ISO 9000 approach)

Pre-production qualification of all materials and shotcrete mixturedesign

Implementation of a systematic quality control inspection andtesting plan for the aggregates, mix water and plastic and

hardened shotcrete Use of nozzlemen and shotcrete batching, supply and application

crew properly trained and qualified

08 Shotcrete Quality Control & Testing for an Underground Mine in Canada

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