Industry experience with ASRIndustry experience with ASR requirements in project specifications

Colin Lobo, Sr. VP Engineering

ASTM Workshop, St. Louis, MOJune, 2010June, 2010

Ideal ASR Specification

Determine reactivity of aggregatesS i d l l hi tService record or local historyTest results of aggregates (a reliable test)

preferably by aggregate supplier (ASTM C33)preferably by aggregate supplier (ASTM C33)

Determine if service conditions need mitigationMoistureCritical nature of structure

Establish mitigative measuresgService record or local historyTest to “accepted” criteria

WWW. NRMCA.ORG

Prescription based on best current understanding

Problems

Number of ASR testsNumber of ASR testsContradicting indications

No “standard” national guide specificationNo standard national guide specificationProject Specifications:

Old provisions proven not to workOld provisions proven not to workAdd on “new” provisionsExtend the recommended criteriaExtend the recommended criteriaInclude all potential protective measuresIncompatible with other performance requirements

WWW. NRMCA.ORG

Incompatible with other performance requirements

Typical clauses

Use non reactive aggregatesUse non reactive aggregatesDiffering tests and criteria

Use a low alkali cementUse a low alkali cement0.6%; 0.4% Na2Oe

Limits on supplementary cementing materialsLimits on supplementary cementing materialsMin and maxCompositional limitsCompositional limits

Document mitigating methodsDiffering tests and criteria

WWW. NRMCA.ORG

Differing tests and criteria

Implications to performance/sustainability

Fast track workRate of strength gainSetting characteristics

Inherent specification / performance conflictsSustainability

Minimize wasteRecycled contentRegional materials

Transportation

WWW. NRMCA.ORG

ASR test methods

Science based – difficult to perform (C289)p ( )Historical precedent (C227)Standard reactive aggregate (C441)Standard reactive aggregate (C441)Presumed to represent service conditions (C342 - withdrawn))Severe conditions to accelerate (C1260)Long period – “more reliable” (C1293)Long period more reliable (C1293)Quacks like a duck… so it must be… (C1567)

WWW. NRMCA.ORG

NRMCA Research – ASTM C1260

80%

90%

100%

50%

60%

70%

80%

nt L

ess

Tha

n

10%

20%

30%

40%

Per

cen

All (152)

CA (71)

0%

10%

0.00 0.10 0.20 0.30 0.40 0.50 0.60

Mortar Bar Expansion, %

FA (81)

154 U.S. aggregates tested by ASTM C 1260:73% expanded more than 0.1% (85% of sands)52% expanded more than 0.2% (65% of sands)

WWW. NRMCA.ORG

p ( )80% have been used in concrete for 10 years or longer

NRMCA - C1260 vs. C1293

0.180.20

ion,

0 120.140.16

te)

expa

nsi

0.080.100.12

93 (c

oncr

et

0 020.040.06

STM

C 1

29

0.000.02

0.0 0.2 0.4 0.6 0.8 1.0 1.2ASTM C 1260 (mortar) expansion %

AS

WWW. NRMCA.ORG

ASTM C 1260 (mortar) expansion, %

Project SpecPC alkali >0.6% can be used when

With slag cement effective alkali of blend does not exceed 0.6%M il bl lk li f t fl h bl d t t d 0 6%Max available alkali for cement-fly ash blend not to exceed 0.6%

Alkalinity measurements on fly ash or cement or combinationAggregates C295

When constituents are exceeded, aggregates are unacceptableAggregates C1260

Expansion > 0.08% at 16 days are unacceptableCoarse aggregate – C289Aggregates failing evaluation criteria can be used with prior field service recordsFly ash not permitted in concrete exposed to public view

Washington Metro Authority

WWW. NRMCA.ORG

g yParking garages

Washington Metro Spec ModifiedIf cement alkalis > 0.6%, test aggregates with proposed PCproposed PC

C1260 Expansion < 0.08 at 16 days

Test aggregate with proposed cementitiousmaterials

C1567 Expansion < 0.08 at 16 days

Washington Metro Authority Dulles Metrorail

WWW. NRMCA.ORG

Dulles Metrorail

FAA Spec

Modify C1260/C1567Modify C1260/C1567Aggregates in proportions proposed for useCementitious materials in proportionsp pSoak in potassium acetate for 28 days

Expansion < 0.10 at 28 days immersionExpansion 0.10 at 28 days immersion

WWW. NRMCA.ORG

Evaluation for FAA

ASTM C1567 - Mortar-Bar immersed in KA solution

0.15

0.20

CA1; 16% f ly ash

CA1; 22% f ly ash Aggregate blend:Coarse:Fine = 63:37

0.10

Cha

nge,

%

CA2; 16% f ly ash

CA2; 22% f ly ash

Coarse:Fine = 63:37

0.05Leng

th C

0.000 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Days in Solution

WWW. NRMCA.ORG

Days in Solution

Actual SpecContractor shall pre-qualify aggregate supplierNon ASR aggregate shall be used for all concretegg gContractor shall test aggregate and concrete mixture frequently while building stockpiles and during pavingTesting at Contractor expenseIncrease time for C1260 to 28 daysProposed aggregate blend tested by C1567Proposed aggregate blend tested by C1567

Andrews Air Force Base

WWW. NRMCA.ORG

Andrews Air Force Base

Qualification data

WWW. NRMCA.ORG

Guidance on ASR Specifications

ACI 318 is silentN t dd d i ACI 301Not addressed in ACI 301

AIA MasterSpec marginally addresses ASRGenerally not addressed in private constructionGenerally not addressed in private construction

DOT requirements vary considerablyFederal specs vary considerablyFederal specs vary considerably

YES G id i d dYES – Guidance is neededFHWA/AASHTO ASTM C09 50 / C01 50

WWW. NRMCA.ORG

ASTM C09.50 / C01.50

Ideal ASR Specification

Determine reactivity of aggregatesS i d l l hi tService record or local historyTest results of aggregates (a reliable test)

preferably by aggregate supplier (ASTM C33)preferably by aggregate supplier (ASTM C33)

Determine if service conditions need mitigationMoistureCritical nature of structure

Establish mitigative measuresgService record or local historyTest to “accepted” criteria

WWW. NRMCA.ORG

Prescription based on best current understanding

AASHTO FHWA Standard

Evaluation of aggregateEvaluation of aggregateService RecordPetrographyPetrographyTest

ASTM C1260ASTM C1260ASTM C1293

Alkali carbonate addressed separately

WWW. NRMCA.ORG

AASHTO FHWA Standard

MitigationMitigationPerformancePrescriptivePrescriptive

WWW. NRMCA.ORG

AASHTO FHWA Standard

PerformancePerformanceC1293 - <0.04% at 2 yearsC1567 <0 10% at 14 days immersionC1567 - <0.10% at 14 days immersion

Complications if lithium is evaluated

WWW. NRMCA.ORG

AASHTO FHWA Standard

PrescriptivePrescriptiveDegree of reactivity – R0, R1, R2, R3Risk of ASR exposureRisk of ASR – exposure

Level 1 – Level 6Classification of structure riskClassification of structure – risk

S1, S2, S3, S4P ti L lPrevention Level

V, W, X, Y, Z, ZZC li ti if lithi i l t d

WWW. NRMCA.ORG

Complications if lithium is evaluated

AASHTO FHWA StandardPrescriptive – based on Prevention Level

Maximum alkali in concreteMaximum alkali in concrete5.0, 4.0, 3.0 lb/yd3

Quantities of SCMs varyQ yFly ash (CaO <18%, Na2Oe)Slag (Na2Oe < 1.0%)Silica Fume (Na Oe < 1 0%; varies based on PC alkali in concrete)Silica Fume (Na2Oe < 1.0%; varies based on PC alkali in concrete)

Adjust quantity of SCM based on PC alkalisLevel ZZLevel ZZ

SCM and concrete alkalis

WWW. NRMCA.ORG

AASHTO FHWA Standard

It’s a great startIt s a great start

Approving ASTM standard will be hardApproving ASTM standard will be hard

S ifi ti i kSpecification risksElevating prevention levelI ti ll ( li i t ti )Incorporating all (eliminate options)Tightening recommended limits

WWW. NRMCA.ORG

Thank you

QuestionsQuestions

WWW. NRMCA.ORG