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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Shotcrete Quality Control and Testing for an Underground Mine in Canada
By Dudley R. (Rusty) Morgan
andMazin Ezzet
AMEC Earth & Environmental, a division of AMEC Americas Limited
SHOTCRETE FOR AFRICA CONFERENCEMisty Hills Conference Centre
South Africa2-3 March, 2009
Subject of Presentation
General IntroductionStandards and CodesShotcrete Materials Requirements
– Cementing Materials– Aggregates– Mixing Water– Chemical Admixtures
Shotcrete Performance Requirements
Subject of Presentation (continued)
Quality Control Testing– Aggregates– Batching and Supply (Plastic Shotcrete)– Hardened Shotcrete
Shotcrete Quality Control Organizational Chart
New Underground Gold Mine in British Columbia
Portal at Decline into Underground Mine
Mobile Mass Batcher Unit Discharging into Ready-Mix Concrete Truck
Remixer Unit for Hauling Shotcrete Down Decline
Remixer Unit Discharging into Shotcrete Pump at Back of Shotcrete Sprayer
Remote Control Shotcrete Sprayer
Manipulator Arm on Remote Control Shotcrete Sprayer
Shooting ASTM C1550 Round Test Panels
Ready for Shotcreting Underground
Drilling Face for next Round of Blasting
Note Shotcrete with Bolts and Plates
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 Manufacturer’s Bureau (CPMP)
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 Voidsin Hardened Concrete
ASTM C642-82
Standard Test Methods for Chemical Analysis of Hydraulic Cements
ASTM C114
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)
Shotcrete Materials
Cementing Materials– Portland Cement: CSA Type GU– Fly Ash: CSA Type F or CI– Silica Fume: CSA Type SF
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 µmA23.2-5A
0.50.5Low-density granular materialsA23.2-4A
0.251Clay lumpsA23.2-3A
Coarse Aggregate
Fine AggregateStandard RequirementsCSA Test Method
Maximum Percentage byMass of Total Sample
Property
Grading Limits for Fine Aggregate
0-380 µm
2-10160 µm
10-35315 µm
25-65630 µm
50-901.25 mm
80-1002.5 mm
95-1005 mm
10010 mm
FA1Sieve Size
Total Passing Sieve, Percentage by Mass
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
Grading Limits for Combined Aggregates
0-380 µm
2-10160 µm
8-20315 µm
20-35630 µm
35-551.25
50-702.5 mm
70-855 mm
90-10010 mm
10014 mm
Total passing sieve, percentage by massSieve Size
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
Perc
ent P
assi
ng
ACI Gradation 1 Limits
ACI Gradation 2 Limits
Combined % Passing
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
Chemical Admixtures
Water Reducing AdmixturesSet Retarding or Hydration Controlling AdmixturesAir Entraining AdmixturesSet Accelerators Added at Nozzle
Fibres
Steel Fibres: ASTM C1116 Type I and ASTM A 820
Synthetic Fibres: ASTM C1116 Type III
Typical Shotcrete Performance Requirements
2 MPaMinimum early age compressive strength before re-entry under shotcrete
Penetrometer as calibrated against beams tested as
equivalent cubes
*Minimum Joules energy at 40 mm deflection in round panel test
ASTM C1550
9 %18 %
Maximum values of boiled absorptionMaximum volume of permeable voids
ASTM C642
10MPa30 MPa40 MPa
Minimum compressive strength of shotcrete cores
1 Day7 Days28 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
Fibre Reinforced Shotcrete Testing in North America
Steel fibre synthetic macro-fibre reinforced shotcrete in NorthAmerica has been tested to the following ASTM Standards:
ASTM C1018: Standard test method for flexural toughness and first-crack strength of fiber-reinforced concrete (using beam with third point loading) first published 1984, withdrawn 2006
ASTM C1609: Standard test method for flexural performance of fiber-reinforced concrete (using beam with third point loading) first published 2005
ASTM C1550: Standard test method for flexural toughness of fiber reinforced concrete (using centrally loaded round panel)
ASTM C1018 and ASTM C1609 Beam Test
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 LevelsMorgan and Chen, 1995
Fibre Shotcrete Beam Tests
ASTM C1609 Load vs Deflection Curve
ASTM C1550 Round Panel Test
ASTM C1550 Round Panel Test
Technical Report
Typical Shotcrete Mixture Design
1.0105Yield (m3) =2354Total
0.0202-2.0At Shot (%)
--2.5Air 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 Fume
0.13653150430Cement Type GU
Volume[m3]
Density [kg/m3]
Mass per m3 SSD Agg [kg]Material
Shotcrete Quality Control Certification and Testing
Production of quality shotcrete in an undergroundenvironment requires:
Rigorous shotcrete specificationsImplementation of a quality management plan (follow ISO 9000 approach)Pre-production qualification of all materials and shotcrete mixture designImplementation of a systematic quality control inspection and testing plan for the aggregates, mix water and plastic and hardened shotcreteUse of nozzlemen and shotcrete batching, supply and application crew properly trained and qualified