15 september 2009 - university of colorado...
TRANSCRIPT
15 September 2009
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Specialist Engineering, Materialsand Environmental Consultants
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Specialist Engineering, Materialsand Environmental Consultants
MANAGEMENT OF AARAFFECTED STRUCTURES :
ANALYSIS, PERFORMANCE ANDPREDICTION
Coyne and Bellier, Paris,Tuesday 15 September 2009
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WHAT IS AAR ?
Dr Ian SimsDirector, RSK STATS Limited, UK
www.stats.co.uk
Dr Ian SimsDr Ian SimsDirector, RSK STATS Limited, UK
www.stats.co.uk
A member of the RSK Group plcA member of the RSK Group plc4
Specialist Engineering, Materialsand Environmental Consultants
Val de laMare Dam,Jersey
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What is AAR?What is RILEM?AAR and its controlling factorsDiagnosis & prognosisPrevention & testingRILEM guidance & application to dams
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What is AAR?What is RILEM?AAR and its controlling factorsDiagnosis & prognosisPrevention & testingRILEM guidance & application to dams
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RILEM TC 219-ACSAlkali-Aggregate Reactions inConcrete andStructures
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RILEM
Founded in 1947 and based in ParisAcronym of French wordsThe International Union of Testing andResearch Laboratories for Materials andStructuresTechnical CommitteesMaterials and StructuresReports
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RILEM & AARTC 106TC 106 - 1988 to 2000Accelerated for AAR potential of aggregatesTC 191-ARPTC 191-ARP - 2000 to 2006Added diagnosis & specificationTC 219-ACSTC 219-ACS - started work in 2006Added performance testing, appraisal &modellingChairman: Dr Philip Nixon
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RILEM & AARTC 106TC 106 - 1988 to 2000Accelerated for AAR potential of aggregatesTC 191-ARPTC 191-ARP - 2000 to 2006Added diagnosis & specificationTC 219-ACSTC 219-ACS - started work in 2006Added performance testing, appraisal &modellingChairman: Dr Philip Nixon
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RILEM TC 191-ARP & TC 219-ACSTC 191-ARP: … to develop integratedassessment, specification & diagnosisprocedures for AAR ...Built on the earlier work of RILEM TC 106International Specification requested 20001st draft at 12th ICAAR in Beijing in 2004TC 191-ARP Completed work in 2006Further development by current TC 219-ACS2nd draft at 13th ICAAR in Trondheim 2008
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Why International Specification?Globalisation - engineers work internationallyGrowth of regional/international StandardsPrinciples of AAR are well established andapply globally without deference to politicalboundariesIncreasing plethora of incompatible testsComplexity of different approachesRILEM proposals accepted by ICAARs
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What is AAR?What is RILEM?AAR and its controlling factorsDiagnosis & prognosisPrevention & testingRILEM guidance & application to dams
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Specialist Engineering, Materialsand Environmental Consultants
Alkali-Aggregate Reactivity
Alkali-Silica Reactivity - ASRcommonest, worldwide examplesAlkali-Silicate Reactivityvariety of ASR, described in CanadaAlkali-Carbonate Reactivity - ACRrare, examples in Canada & ChinaCombined ASR & ACR possible‘ACR’ might not exist!
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Alkali-Aggregate Reactivity
Alkali-Silica Reactivity - ASRcommonest, worldwide examplesAlkali-Silicate Reactivityvariety of ASR, described in CanadaAlkali-Carbonate Reactivity - ACRrare, examples in Canada & ChinaCombined ASR & ACR possible‘ACR’ might not exist!
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Alkali-Silica Reactivity
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Alkali-Silica ReactionA simplification - in concrete:Potentially reactive silica in aggregate+ Alkali hydroxides from cement= Alkali-silica gel+ Further water absorbed by the gel= Swelling, expansion & damage
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Alkali-Silica Reactivity
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Alkali-Silica Reactivity
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Alkali-Silica Reactivity
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ASR with Greywacke
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ASR with Greywacke
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Alkali-Silica Reactivity
ASR needs all the following:Sufficient alkalis:mainly from the cementCritical amount of reactive aggregate:might be small % of total - ‘pessimum’Sufficient moisture:includes all external & >75% RH
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Other FactorsDamaging ASR also needs:
Calcium hydroxide:low-calcium gel is less- or non-expansiveSwelling type of gel product:lithium can modify the gel characteristicsLimited facility for gel accommodation:porous concrete or aggregate less affectedEffects of temperature - internal & externalEffects of scale and long service life?
Damaging ASR also needs:Calcium hydroxide:low-calcium gel is less- or non-expansiveSwelling type of gel product:lithium can modify the gel characteristicsLimited facility for gel accommodation:porous concrete or aggregate less affectedEffects of temperature - internal & externalEffects of scale and long service life?
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Reassurance & Risks
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Reassurance & RisksCracking is superficialCracking is superficial
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Reaction and Cracking
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Reaction and Cracking
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Reassurance & RisksCracking is superficialPerformance less impaired than appearsCracking is superficialPerformance less impaired than appears
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Restraint of Expansion
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Reassurance & RisksCracking is superficialPerformance less impaired than appearsCracking is superficialPerformance less impaired than appears
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Alkali-Silica Reactivity
Minimising the risk of ASR in new work:Concrete Society TR30 (latest 1999)& BRE Digest 330Eliminate one or more of the 3 factors:- Limit alkali content - preferred in UK- Use non- or less reactive aggregate- Exclude moisture
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UK Specification - Digest 330
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UK Specification - CS TR30
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InternationalRILEM: tests, diagnosis, specificationICOLD: updating bulletinNational guidanceHow special are dams?
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Alkali-Aggregate Reactivity
Alkali-Silica Reactivity - ASRcommonest, worldwide examplesAlkali-Silicate Reactivityvariety of ASR, described in CanadaAlkali-Carbonate Reactivity - ACRrare, examples in Canada & ChinaCombined ASR & ACR possible‘ACR’ might not exist!
15 September 2009
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What is AAR?What is RILEM?AAR and its controlling factorsDiagnosis & prognosisPrevention & testingRILEM guidance & application to dams
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Diagnosis & PrognosisNot appraisal of affected structuresSite inspection + petrography & analysisAAR usually identifiableNot necessarily expansive!Other causes of damage less obvious?Combinations of causes?Testing or monitoring for prognosis
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Site AssessmentDamage or deteriorationDamage or deterioration
ASR in theBritishIsles
Val de laMare Dam,Jersey
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Site Assessment
Displacement
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Site AssessmentDamage or deteriorationDamage or deterioration
Maentwrog Dam - ASR caused by greywacke42
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Site AssessmentDamage or deterioration & gel depositsDamage or deterioration & gel deposits
MaentwrogDam -
long-termASR and
watermigration
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Site AssessmentDamage or deterioration & no gel depositsDamage or deterioration & no gel deposits
Bridge in New Brunswick, Canada - argillite aggregate44
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Concrete PetrographySampling
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Concrete Petrography
Sampling
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Concrete Petrography
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Concrete PetrographyTechniquesTechniques
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Concrete PetrographyTechniquesTechniques
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Concrete PetrographyTechniquesTechniques
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Gathering the evidence -thin-section microscopy
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Concrete PetrographyDamage or deteriorationDamage or deterioration
Reaction site under microscope in thin-section52
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Concrete PetrographyDamage or deteriorationDamage or deterioration
Gel deposits - infilling void54
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Concrete PetrographyDamage or deteriorationDamage or deterioration
Gel deposits - in peripheral crack
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Concrete Petrography
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Concrete PetrographyA directobservationtechnique!
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Concrete PetrographyDamage or deteriorationDamage or deterioration
Gel detected using uranyl acetate
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Alkali-Reactivity - CarbonatesCarbonate aggregatesAlkali-carbonate reaction – ACRCanada & especially now ChinaACR usually occurs much sooner than ASRBoth ACR & ASR in same material?ASR masquerading as ACR in some cases?RILEM developed assessment methodsDoes ACR really exist?
Carbonate aggregatesAlkali-carbonate reaction – ACRCanada & especially now ChinaACR usually occurs much sooner than ASRBoth ACR & ASR in same material?ASR masquerading as ACR in some cases?RILEM developed assessment methodsDoes ACR really exist?
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Concrete PetrographyDamage or deteriorationDamage or deterioration
Pavement in Cornwall, Ontario, Canada60
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Concrete PetrographyDamage or deteriorationDamage or deterioration
Reactive Carbonate Texture
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Concrete PetrographyDamage or deteriorationDamage or deterioration
Non-expansive ACR, Libya62
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Diagnosis - Caution!Do not jump to conclusionsNot all concrete expansion is AARDelayed ettringite formation (DEF)?Combinations of evidenceOther sulfate reactionsOther causes of cracking & damage
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Delayed Ettringite Formation
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Case Study
Concrete silos in Saudi ArabiaCracking and detachment of coverAlleged ‘alkali-carbonate reaction’Actually thermal crackingNon-expansive carbonate reactionImportance of careful investigation
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15 September 2009
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15 September 2009
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PrognosisIf AAR has been establishedWill reaction continue & damage get worse?Monitoring?Modelling increasingly practicableDirect testing of concrete samples?Indicative - but caution required!
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BCA Core Test Arrangement
Demec gauge measuringstuds
End point measuringstuds on adhesive
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Core Test Results
Demec Studs
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
0 50 100 150 200 250 300 350 400
Elapsed time (Days)
Expa
nsio
n (M
icro
stra
in) C1
C3C4C6C9C11C12C14
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What is AAR?What is RILEM?AAR and its controlling factorsDiagnosis & prognosisPrevention & testingRILEM guidance & application to dams
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Alkali-Silica Reactivity
ASR needs all the following:Sufficient alkalis:mainly from the cementCritical amount of reactive aggregate:might be small % of total - ‘pessimum’Sufficient moisture:includes all external & >75% RH
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RILEM ProceduresAAR-0 : the key - outline & criteriaAAR-1 : petrographical examinationAAR-2 : accelerated mortar-bar testAAR-3 : 38oC concrete prism testAAR-4.1 : 60oC accelerated concrete prismAAR-5 : carbonate aggregate assessmentAAR-6.1 : diagnosis & prognosisAAR-7.1 & 7.2 : specifications - ASR & ACRAAR-8 : releasable alkalis
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RILEM ProceduresAAR-0 : the key - outline & criteriaAAR-1 : petrographical examinationAAR-2 : accelerated mortar-bar testAAR-3 : 38oC concrete prism testAAR-4.1 : 60oC accelerated concrete prismAAR-5 : carbonate aggregate assessmentAAR-6.1 : diagnosis & prognosisAAR-7.1 & 7.2 : specifications - ASR & ACRAAR-8 : releasable alkalis
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RILEM International SpecificationAAR-7.1 – Alkali-silica reactions(ASR)Principles: Damaging ASR needs simultaneous occurrence of:
A sufficiently alkaline pore solutionA critical amount of reactive silicaA sufficient supply of water
Specification based on ensuring absence of at least oneAllow for interactions other environmental actions:
Freezing/thawingDe-icing saltsMarine atmosphere
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AAR-7.2 - Carbonate aggregatesGenerally not susceptible to AAR but
vulnerable in some circumstances:Contains finely divided SiO2
ASR and AAR-7.1 measures appropriate.Dolomitic carbonate rocks.
Mechanism still controversialOptions for control are limitedPrimarily identification & avoidance ofpotentially susceptible aggregatesPerhaps use of very high levels of ggbs?
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AAR-7 International SpecificationOverall Structure:
Two basic stages:Determine necessary Level of PrecautionIdentify any preventative or PrecautionaryMeasures appropriate to that Level ofPrecaution
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Determining the Level ofPrecaution
The level of precaution will depend on:
The consequences of damage- structural needs and service life
The likelihood of damage - the environment to which the concrete isexposed
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S1Low risk
N on-load-bearing e lem ents inside bu ild ings Tem porary or short life structures Sm all num bers of easily rep laceable elem ents M ost low rise dom estic structures
S2N orm al risk
M ost build ings and civ il eng ineering structures P recast elem ents w here costs o f replacem ent h igh
S3H igh risk
Long service life or h igh ly critica l structures w here deteriora tionunacceptab le e.g.
N uclear insta lla tions D am s Tunnels Exceptionally im portant bridges and viaducts S tructures retaining hazardous m aterials C ritica l elem ents very d ifficult to inspect or repa ir S tructures where loss of function is unacceptab le
Categorisation of structural risk
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S1Low risk
N on-load-bearing e lem ents inside bu ild ings Tem porary or short life structures Sm all num bers of easily rep laceable elem ents M ost low rise dom estic structures
S2N orm al risk
M ost build ings and civ il eng ineering structures P recast elem ents w here costs o f replacem ent h igh
S3H igh risk
Long service life or h igh ly critica l structures w here deteriora tionunacceptab le e.g.
N uclear insta lla tions D am s Tunnels Exceptionally im portant bridges and viaducts S tructures retaining hazardous m aterials C ritica l elem ents very d ifficult to inspect or repa ir S tructures w here loss of function is unacceptable
Categorisation of structural risk
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Likelihood of damage:Characterising the Environment
Three levels of environmental categorisation are proposed:E1 protected from external moistureE2 exposed to external moistureE3 exposed to external moisture and additionally to
aggravating factorse.g. freezing /thawing, de-icing salts, marine environment,prolonged elevated temperatures
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Likelihood of damage:Characterising the Environment
Three levels of environmental categorisation are proposed:E1 protected from external moistureE2 exposed to external moistureE3 exposed to external moisture and additionally to
aggravating factorse.g. freezing /thawing, de-icing salts, marine environment,prolonged elevated temperatures
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Likelihood of damage:Characterising the Environment
Three levels of environmental categorisation are proposed:E1 protected from external moistureE2 exposed to external moistureE3 exposed to external moisture and additionally to
aggravating factorse.g. freezing /thawing, de-icing salts, marine environment,prolonged elevated temperatures
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Level of Precaution
Structural and environmental categories are combined to givethree levels of precaution:
P1: No special precautions against ASRP2: Normal level of precaution against ASRP3: Special level of precautionP4: Extraordinary level of precaution
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Level of PrecautionEnvironment E1 E2 E3
Structural risk
S1 P1 P1 P1
S2 P1 P2 P3
S3 P2* P4 P4
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Level of PrecautionEnvironment E1 E2 E3
Structural risk
S1 P1 P1 P1
S2 P1 P2 P3
S3 P2* P4 P4
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Level of PrecautionEnvironment E1 E2 E3
Structural risk
S1 P1 P1 P1
S2 P1 P2 P3
S3 P2* P4 P4
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Level of PrecautionEnvironment E1 E2 E3
Structural risk
S1 P1 P1 P1
S2 P1 P2 P3
S3 P2* P4 P4
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Level of PrecautionEnvironment E1 E2 E3
Structural risk
S1 P1 P1 P1
S2 P1 P2 P3
S3 P2* P4 P4
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Level of PrecautionStructural and environmental categories are
combined to give three levels of precaution:
P1: No special precautions against ASRP2: Normal level of precaution against ASRP3: Special level of precautionP4: Extraordinary level of precaution
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Level of PrecautionStructural and environmental categories are
combined to give three levels of precaution:
P1: No special precautions against ASRP2: Normal level of precaution against ASRP3: Special level of precautionP4: Extraordinary level of precaution
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Precautionary MeasuresP1 – No special precautionsP2 – Normal level of precaution:One of 4 Precautionary Measures:M1, M2, M3, M4
P3 - Special level of precaution:P2 + design to resist aggravating factors
P4 – Extraordinary level of precautionCombined application of two or more measures
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Precautionary MeasuresP1 – No special precautionsP2 – Normal level of precaution:One of 4 Precautionary Measures:M1, M2, M3, M4
P3 - Special level of precaution:P2 + design to resist aggravating factors
P4 – Extraordinary level of precautionCombined application of two or more measures
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Precautionary Measures
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gel
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Precautionary Measures
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gel
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Precautionary Measure M1Controlling the alkali content of the concrete- cement & other constituents- thesholds vary with aggregate reactivity- low, medium (>4.0kg/m3) or high(<4.0kg/m3)Use of low alkali cementInclusion of sufficient gbfs, fly ash (pfa),silica fume, metakaolin or other pozzolana
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Precautionary Measures
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gel
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Precautionary Measures
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gel
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Precautionary Measures
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gel
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Precautionary MeasuresCan they work with dams?
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gel
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Precautionary MeasuresCan they work with dams?
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gelM2 & M3 might be impracticable
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Precautionary MeasuresCan they work with dams?
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gelM4 might be too expensive, even if thelithium dosage can be determined
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Precautionary Measures - Problem?P1 – No special precautionsP2 – Normal level of precaution:One of 4 Precautionary Measures:M1, M2, M3, M4
P3 - Special level of precaution:P2 + design to resist aggravating factors
P4 – Extraordinary level of precautionCombined application of two or more measures
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Precautionary MeasuresProposed Solutions
M1 - Controlling alkali contentM2 - Non-reactive aggregate combinationM3 - Preventing moisture accessM4 - Ensuring non-expansive gel
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Precautionary Measure M1Controlling the alkali content of the concrete- cement type & contentUse of low alkali cementInclusion of sufficient gbfs, fly ash (pfa),silica fume, metakaolin or other pozzolana
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Precautionary Measure M1Controlling the alkali content of theconcrete- cement type & contentUse of low alkali cementInclusion of sufficient gbfs, fly ash (pfa),silica fume, metakaolin or other pozzolanaTwo separate M1 items for P4 level?
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Precautionary Measure M1Controlling the alkali content of theconcrete- cement type & contentUse of low alkali cementInclusion of sufficient gbfs, fly ash (pfa),silica fume, metakaolin or other pozzolanaTwo separate M1 items for P4 level?Plus design issues - fibre reinforcement?
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AAR-7.2 - Carbonate Aggregates
Key issue – identifying potentiallysusceptible aggregates
History of use is good guide whereapplicable
If no local knowledge RILEM methods canbe used
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Identifying potentially deleteriouscarbonate rocksPetrographical examination (AAR-1).If possible carbonate reactivity (impureand/or dolomitic limestone:Use RILEM AAR-5 procedure:(rapid preliminary screening test forcarbonate aggregates): combined AAR-2 &new AAR-5AAR-5 is similar to AAR-2 but uses 4/8mminstead of 0/2mm aggregate grading
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Possible outcomes of AAR-2/AAR-5AAR-2 > criteria in AAR-0AAR-5 < AAR-2 by at least 0.01%- potential for ASR reaction: apply Part 1 measures
AAR-2 > criteria in AAR-0AAR-5 > AAR-2- potential for carbonate reaction: apply MC1 or MC2
AAR-2 < criteria in AAR-0AAR-5 < AAR-2 by at least 0.01%- no special precautions
AAR-2 < criteria in AAR-0AAR-5 > AAR-2- potential for carbonate reaction: apply MC1 or MC2
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Precautionary Measures forPotentially Reactive CarbonateRocksTentative RILEM suggestionsMC1: Identification & rejection of susceptibleaggregateMC2: Use of very high replacement levels ofblastfurnace slag in cementPerformance testing needed for MC2
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Performance TestingParticular objective of RILEM TC 219-ACSProbably based upon AAR-4.1 (AAR-4.2)60oC accelerated concrete prism testApplicable to actual or proposed concretemixesApplicable on a project-specific basisValidating method against field performance
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Prevention SummaryAAR-7.1 & 7.2 proposed by RILEMLevel of Precaution - structure & environmentPrecautionary Measures for each LevelDams likely to be P4P4 needs 2 Measures + any further protectionSpecial proposals included for damsTentative guidance for reactive carbonateAAR-4.2 performance test being developed
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What is AAR?What is RILEM?AAR and its controlling factorsDiagnosis & prognosisPrevention & testingRILEM guidance & application to dams
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RILEM ProceduresAAR-0 : the key - outline & criteriaAAR-1 : petrographical examinationAAR-2 : accelerated mortar-bar testAAR-3 : 38oC concrete prism testAAR-4.1 : 60oC accelerated concrete prismAAR-5 : carbonate aggregate assessmentAAR-6.1 : diagnosis & prognosisAAR-7.1 & 7.2 : specifications - ASR & ACRAAR-8 : releasable alkalis
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RILEM methods overall guideAAR-0
Integrated assessment procedureDraft published in Materials & Structures, August-September
2003
Under continual review -TC now prepared updated version,
including annex for assessing carbonate aggregates
To be published in Materials & Structuresor as part of a RILEM Report
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RILEM methods overall guideAAR-1
Petrographic methodPublished in Materials & Structures,
August-September 2003
Possibly to be re-published as part of a RILEM Report
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Opal Vein in Limestone
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Gel-Pat Testing for Opal
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Strained Quartz
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Reactive Carbonate Texture
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Aggregate Assessment to AAR-1
Interpretation & classification:
- unlikely to be alkali-reactive - Class I
- potentially alkali-reactive - Class II sub-divided for silica, carbonate or silica & carbonate
- very likely to be alkali-reactive - Class III
Pictorial atlas in preparation
Interpretation & classification:
- unlikely to be alkali-reactive - Class I
- potentially alkali-reactive - Class II sub-divided for silica, carbonate or silica & carbonate
- very likely to be alkali-reactive - Class III
Pictorial atlas in preparation
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RILEM methods overall guideAAR-2
Accelerated mortar bar test - AMBTDraft published as TC 106-2 in Materials and Structures, June
2000
TC completed a revised edition,based largely on PARTNER recommendations
To be published in Materials & Structures,or as part of a RILEM Report
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Inter-laboratory trial ofaccelerated mortar bar test (AAR-2)
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0.1
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ZA 1
RA
2
RA
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GB
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B 1
GB
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IRL
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B 9
IND
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IRL
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RA
5
B 5
GB
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ZA 3
RA
4
IND
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GB
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Aggregate combinations from 10 countries
Exp
ansi
on (%
) @ 1
4 da
ys ExpansiveAnomalous (possibly a porous flint content)Non-expansive
Expansive
Non expansive
Potentially expansive
Field experience:
--Tentative criteria
138
Specialist Engineering, Materialsand Environmental Consultants
RILEM methods overall guideAAR-3
38°C Concrete prism test - CPTDraft Published as TC 106-3 in Materials and Structures, June
2000
TC completed a revised edition,based largely on PARTNER recommendations
To be published in Materials & Structures,or as part of a RILEM Report
15 September 2009
24
139
Specialist Engineering, Materialsand Environmental Consultants
Inter-laboratory trial of 38°Cconcrete prism test method (AAR-3)
Figure 2: Concrete prim test trials
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
RA
3
GB
3
GB
4
GB
2
I 3B B3 B4 B2 B1
ZA 1 IS1
I 1B
ZA 2
IND
1
N 1
RA
2 B8
I 3 A
RA
1
RA
4 B6 B7 I 2B B5 I 4B
IND
2
GB
1
I 2A
I 4A
GB
6
I 1A
N 2
ZA 3
ZA 4
GB
5
IS2
IS3
Aggregate combinations from 10 countries(B suffix indicates enhanced alkali content in test)
Exp
ansi
on (%
) @ 1
yea
r
Expansive
Anomalous (aggregate type needs enhanced alkali content in test)
Non-expansive
Expansive
Non expansive
Possibly expansive
--Tentative criteria
Field experience:
140
Specialist Engineering, Materialsand Environmental Consultants
RILEM methods overall guideAAR-4
60°C Accelerated concrete prism testInternational trial completed
TC currently finalising AAR-4.1(accelerated aggregate test)
To be published in Materials & Structures,or as part of a RILEM Report
141
Specialist Engineering, Materialsand Environmental Consultants
Inter-laboratory trial of 60°C accelerated concrete prism test (AAR-4.1)
Expansion after 20 weeks
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
1/R1
1/R1
1/R1
2/R1
3/R1
4/R1
5/R1
5/L1
6/R1
6/L1
7/R1
7/L1
8/L1
9/R1
9/L1
9/L1a
10/R1
11/R1
11/L1
1/R2
1/R2
1/R2
2/R2
3/R2
3/L2
4/R2
5/R2
5/L2
5/L2a
6/R2
6/L2
7/R2
7/L2
8/R2
8/L2
9/R2
9/L2
10/R2
11/R2
12/L2
12/L2a
12/L2x
12/L2y
Participant / Mix
Expa
nsio
n (%
)
Non-reactive aggregate Reactive aggregate
142
Specialist Engineering, Materialsand Environmental Consultants
Inter-laboratory trial of 60°C accelerated concrete prism test (AAR-4.1)
Expansion after 20 weeks
0.000
0.050
0.100
0.150
0.200
0.250
1 2 3 4 5 6 7 8 9 10 11 12
Participant
Expa
nsio
n, %
R1Non- reactive
R2Ref. reactive
143
Specialist Engineering, Materialsand Environmental Consultants
Inter-laboratory trial of 60°C accelerated concrete prism test (AAR-4.1)
Tentative Recommended Criteria:
144
Specialist Engineering, Materialsand Environmental Consultants
Inter-laboratory trial of 60°C accelerated concrete prism test (AAR-4.1)
Tentative Recommended Criteria:
Combination non-reactive: 0.03% or lessCombination non-reactive: 0.03% or less
15 September 2009
25
145
Specialist Engineering, Materialsand Environmental Consultants
Inter-laboratory trial of 60°C accelerated concrete prism test (AAR-4.1)
Tentative Recommended Criteria:
Combination non-reactive: 0.03% or lessCriterion might be relaxed to 0.04%Combination non-reactive: 0.03% or lessCriterion might be relaxed to 0.04%
146
Specialist Engineering, Materialsand Environmental Consultants
Inter-laboratory trial of 60°C accelerated concrete prism test (AAR-4.1)
Tentative Recommended Criteria:
Combination non-reactive: 0.03% or lessCriterion might be relaxed to 0.04%Initial decision no sooner than 15 weeks
Combination non-reactive: 0.03% or lessCriterion might be relaxed to 0.04%Initial decision no sooner than 15 weeks
147
Specialist Engineering, Materialsand Environmental Consultants
Inter-laboratory trial of 60°C accelerated concrete prism test (AAR-4.1)
Tentative Recommended Criteria:
Combination non-reactive: 0.03% or lessCriterion might be relaxed to 0.04%Initial decision no sooner than 15 weeksFinal decision usually at 20 weeks
Combination non-reactive: 0.03% or lessCriterion might be relaxed to 0.04%Initial decision no sooner than 15 weeksFinal decision usually at 20 weeks
148
Specialist Engineering, Materialsand Environmental Consultants
RILEM methods overall guideAAR-5
Rapid Preliminary Screening Testfor Carbonate Aggregates
Draft Published in Materials and Structures, October 2005
Comparison:AAR-2 (0/2mm favouring ASR) &AAR-5 (4/8mm favouring ACR)
149
Specialist Engineering, Materialsand Environmental Consultants
RILEM methods overall guideAAR-8
Aggregate test - releasable alkalis
Draft procedure under review by TCbased on extraction using alkaline solutions
International trial being arranged
150
Specialist Engineering, Materialsand Environmental Consultants
AAR-0Integrated Aggregate Assessment
Phase 1 - Initial characterisation andclassification using AAR-1Phase 2 - Rapid screening tests using AAR-2and AAR-5Phase 3 - Concrete expansion tests usingAAR-3 and/or AAR-4.1
Phase 1 - Initial characterisation andclassification using AAR-1Phase 2 - Rapid screening tests using AAR-2and AAR-5Phase 3 - Concrete expansion tests usingAAR-3 and/or AAR-4.1
15 September 2009
26
151
Specialist Engineering, Materialsand Environmental Consultants
AAR-0Integrated Aggregate Assessment
AAR-1 Petrographical Examination Carried Out?
Yes No
Class I Class II or III
No further action required
Silica IIS (IIIS) Silica & Carbonate IISC (IIISC) Carbonate IIC (IIIC)
Rapid Screening Test? Rapid Screening Test?
YesYes No
Both AAR-2 and AAR-5 Concrete Microbar Test
AAR-2 Ultra-accelerated Mortar Bar Test
Non-reactive
Reactive or Potentially Reactive
Non-reactive
Reactive or Potentially Reactive
AAR-4 Ultra-accelerated (60ºC) Concrete Prism Test
Either And/or
ASR and/or Carbonate Reactivity
ASR only
Petr og raph y R
apid Sc reeni ng Te stsC
o ncret e E xpa ns ion Te sting
No
AAR-3 Conventional (38ºC) Concrete Prism Test 152
Specialist Engineering, Materialsand Environmental Consultants
AAR-0Integrated Aggregate Assessment
AAR-1 Petrographical Examination Carried Out?
Yes No
Class I Class II or III
No further action required
Silica IIS (IIIS) Silica & Carbonate IISC (IIISC) Carbonate IIC (IIIC)
Rapid Screening Test? Rapid Screening Test?
YesYes No
Both AAR-2 and AAR-5 Concrete Microbar Test
AAR-2 Ultra-accelerated Mortar Bar Test
Non-reactive
Reactive or Potentially Reactive
Non-reactive
Reactive or Potentially Reactive
AAR-4 Ultra-accelerated (60ºC) Concrete Prism Test
Either And/or
ASR and/or Carbonate Reactivity
ASR only
Pet rog ra phy Rap id Scr ee nin g T es ts
Co ncre te Ex pan sio n Tes tin g
No
AAR-3 Conventional (38ºC) Concrete Prism Test
153
Specialist Engineering, Materialsand Environmental Consultants
AAR-0Integrated Aggregate Assessment
AAR-1 Petrographical Examination Carried Out?
Yes No
Class I Class II or III
No further action required
Silica IIS (IIIS) Silica & Carbonate IISC (IIISC) Carbonate IIC (IIIC)
Rapid Screening Test ? Rapid Screening Test ?
YesYes No
Both AAR-2 and AAR-5 Concrete Microbar Test
AAR-2 Ultra-accelerated Mortar Bar Test
Non-reactive
Reactive or Potentially Reactive
Non-reactive
Reactive or Potentially Reactive
AAR-4 Ultra-accelerated (60ºC) Concrete Prism Test
Either And/or
ASR and/or Carbonate Reactivity
ASR only
Petro graphy R ap id Scre eni ng T es ts
Con cre te E xpansi on T estin g
No
AAR-3 Conventional (38ºC) Concrete Prism Test154
Specialist Engineering, Materialsand Environmental Consultants
Resumé - What is AAR?What is RILEM?AAR and its controlling factorsDiagnosis & prognosisPrevention & testingRILEM guidance & application to dams
155
Specialist Engineering, Materialsand Environmental Consultants
Key IssuesRILEM TCs seeking international solutionsImproved understanding of ASR & factorsACR might not exist as a separate reactionGood petrography central to diagnosisRILEM TCs developed agreed proceduresSeparate specifications for ASR & ACRTentative added proposals for dams
156
Specialist Engineering, Materialsand Environmental Consultants
The EndThe End
15 September 2009
27
157
Specialist Engineering, Materialsand Environmental Consultants
Thank you for your attention
158
Specialist Engineering, Materialsand Environmental Consultants
Materials Consultancy
RSK STATS Limited18 Frogmore Road, Hemel Hempstead,Hertfordshire, HP3 9RT, United Kingdom
Tel: +44 (0)1442 416674Fax: +44 (0)1442 437550Contact: Dr Ian Sims
e-mail: [email protected]
RSK STATS Limited18 Frogmore Road, Hemel Hempstead,Hertfordshire, HP3 9RT, United Kingdom
Tel: +44 (0)1442 416674Fax: +44 (0)1442 437550Contact: Dr Ian Sims
e-mail: [email protected]