ASTM C1778-14
(Guide)Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete
Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete
SIGNIFICANCE AND USE
5.1 This guide provides recommendations for identifying the potential for deleterious AAR and selecting appropriate preventive measures, based on a prescriptive-based or performance approach, to minimize the risk of deleterious reaction. In regions where occurrences of AAR are rare or the aggregate sources in use have a satisfactory field performance record verified by following the guidance in this standard, it is reasonable to continue to rely on the previous field history without subjecting the aggregates to laboratory tests for AAR. In regions where AAR problems have occurred or the reactivity of aggregates is known to vary from source to source, it may be necessary to follow a testing program to determine potential reactivity and evaluate preventive measures. In this guide, the level of prevention required is a function of the reactivity of the aggregate, the nature of the exposure conditions (especially availability of moisture), the criticality of the structure, and the availability of alkali in the concrete.
5.2 Risk Evaluation—To use this guide effectively, it is necessary to define the level of risk that is acceptable, as this will determine the type and complexity of testing (Note 1). The risk of deleterious expansion occurring as a result of a failure to detect deleteriously reactive aggregates can be reduced by routine testing using petrography, or laboratory expansion tests, or both.
Note 1: The level of risk of alkali-silica reaction will depend upon the nature of the project (criticality of the structure and anticipated exposure). The determination of the level of risk is generally associated with the responsible individual in charge of the design, commonly a representative of the owner, and for structures designed in accordance with ACI 318, the level of acceptable risk would be determined by the licensed design professional.
5.3 Preventive measures determined by either performance testing or the prescriptive approach described in this guide...
SCOPE
1.1 This guide provides guidance on how to address the potential for deleterious alkali aggregate reaction (AAR) in concrete construction. This guide addresses the process of identifying both potentially alkali-silica reactive (ASR) and alkali-carbonate reactive (ACR) aggregates through standardized testing procedures and the selection of mitigation options to minimize the risk of expansion when ASR aggregates are used in concrete construction. Mitigation methods for ASR aggregates are selected using either prescriptive or performance-based alternatives. Preventive measures for ACR aggregates are limited to avoidance of use. Because the potential for deleterious reactions depends not only on the concrete mixture but also the in-service exposure, guidance is provided on the type of structures and exposure environments where AAR may be of concern.
1.2 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: C1778 − 14
StandardGuide for
Reducing the Risk of Deleterious Alkali-Aggregate Reaction
in Concrete
This standard is issued under the fixed designation C1778; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope C125 Terminology Relating to Concrete and Concrete Ag-
gregates
1.1 This guide provides guidance on how to address the
C150/C150M Specification for Portland Cement
potential for deleterious alkali aggregate reaction (AAR) in
C294 Descriptive Nomenclature for Constituents of Con-
concrete construction. This guide addresses the process of
crete Aggregates
identifying both potentially alkali-silica reactive (ASR) and
C295 Guide for Petrographic Examination ofAggregates for
alkali-carbonate reactive (ACR) aggregates through standard-
Concrete
ized testing procedures and the selection of mitigation options
C311 Test Methods for Sampling and Testing Fly Ash or
to minimize the risk of expansion when ASR aggregates are
Natural Pozzolans for Use in Portland-Cement Concrete
used in concrete construction. Mitigation methods for ASR
C586 Test Method for PotentialAlkali Reactivity of Carbon-
aggregates are selected using either prescriptive or
ate Rocks as Concrete Aggregates (Rock-Cylinder
performance-based alternatives. Preventive measures for ACR
Method)
aggregates are limited to avoidance of use. Because the
C595 Specification for Blended Hydraulic Cements
potential for deleterious reactions depends not only on the
C618 Specification for Coal Fly Ash and Raw or Calcined
concrete mixture but also the in-service exposure, guidance is
Natural Pozzolan for Use in Concrete
provided on the type of structures and exposure environments
C823/C823M Practice for Examination and Sampling of
where AAR may be of concern.
Hardened Concrete in Constructions
1.2 Units—The values stated in either SI units or inch-
C856 Practice for Petrographic Examination of Hardened
pound units are to be regarded separately as standard. The
Concrete
values stated in each system may not be exact equivalents;
C989 Specification for Slag Cement for Use in Concrete and
therefore,eachsystemshallbeusedindependentlyoftheother.
Mortars
Combining values from the two systems may result in noncon-
C1105 Test Method for Length Change of Concrete Due to
formance with the standard.
Alkali-Carbonate Rock Reaction
1.3 This standard does not purport to address all of the
C1157 Performance Specification for Hydraulic Cement
safety concerns, if any, associated with its use. It is the
C1240 Specification for Silica Fume Used in Cementitious
responsibility of the user of this standard to establish appro-
Mixtures
priate safety and health practices and determine the applica-
C1260 Test Method for Potential Alkali Reactivity of Ag-
bility of regulatory limitations prior to use.
gregates (Mortar-Bar Method)
C1293 Test Method for Determination of Length Change of
2. Referenced Documents
Concrete Due to Alkali-Silica Reaction
2.1 ASTM Standards:
C1567 Test Method for Determining the Potential Alkali-
C33/C33M Specification for Concrete Aggregates
Silica Reactivity of Combinations of Cementitious Mate-
rials and Aggregate (Accelerated Mortar-Bar Method)
This guide is under the jurisdiction ofASTM Committee C09 on Concrete and
2.2 ACI Standard:
Concrete Aggregates and is the direct responsibility of Subcommittee C09.50 on
Risk Management for Alkali Aggregate Reactions. ACI 318 Building Code Requirements for Structural Con-
Current edition approved Oct. 1, 2014. Published November 2014. DOI:
crete and Commentary
10.1520/C1778-14.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican Concrete Institute (ACI), P.O. Box 9094, Farmington
the ASTM website. Hills, MI 48333-9094, http://www.concrete.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1778 − 14
2.3 AASHTO Standard: expansion and cracking of concrete elements when exposed to
AASHTO PP 65 Standard Practice for Determining the moisture, leading to a reduction in the service life of concrete
Reactivity of Concrete Aggregates and Selecting Appro- structures.
priate Measures for Preventing Deleterious Expansion in
4.2 This guide describes approaches for identifying poten-
New Concrete Construction
tially deleteriously reactive aggregates and selecting appropri-
2.4 CSA Standards:
ate preventive measures to minimize the risk of expansion
A23.2-26A Determination of PotentialAlkali-Carbonate Re-
when such aggregates are used in concrete in exposure
activity of Quarried Carbonate Rocks by Chemical Com-
environments where AAR may be of concern. Preventive
position
measures include avoiding use of the reactive aggregate,
A23.2-27A Standard Practice to Identify Degree of Alkali-
limitingthealkaliloadingoftheconcrete,usingsupplementary
Aggregate Reactivity of Aggregates and to Identify Mea-
cementitious materials, using lithium-based admixtures, or a
sures to Avoid Deleterious Expansion in Concrete
combination of these strategies.
A23.2-28A Standard Practice for Laboratory Testing to
Demonstrate the Effectiveness of Supplementary Cement-
5. Significance and Use
ing Materials and Lithium-Based Admixtures to Prevent
5.1 This guide provides recommendations for identifying
Alkali-Silica Reaction in Concrete
the potential for deleterious AAR and selecting appropriate
3. Terminology
preventive measures, based on a prescriptive-based or perfor-
mance approach, to minimize the risk of deleterious reaction.
3.1 Definitions:
In regions where occurrences ofAAR are rare or the aggregate
3.1.1 For definitions of terms used in this Guide, refer to
sources in use have a satisfactory field performance record
Terminology C125 and Descriptive Nomenclature C294.
verified by following the guidance in this standard, it is
3.2 Definitions of Terms Specific to This Standard:
reasonable to continue to rely on the previous field history
3.2.1 alkali content, n—the alkali content of the cement
without subjecting the aggregates to laboratory tests for AAR.
expressed as % Na O and calculated as Na O + (0.658 K O).
2 eq 2 2
InregionswhereAARproblemshaveoccurredorthereactivity
3.2.2 alkali loading, n—the total amount of alkalies in the
ofaggregatesisknowntovaryfromsourcetosource,itmaybe
3 3
concrete mixture expressed in kg/m or lb/yd ; this is calcu-
necessary to follow a testing program to determine potential
lated by multiplying the portland cement content of the
reactivity and evaluate preventive measures. In this guide, the
3 3
concrete in kg/m or lb/yd by the alkali content of the cement
levelofpreventionrequiredisafunctionofthereactivityofthe
divided by 100.
aggregate, the nature of the exposure conditions (especially
3.2.3 deleteriously reactive, adj—used to describe aggre- availability of moisture), the criticality of the structure, and the
gates that undergo chemical reactions that subsequently result availability of alkali in the concrete.
in premature deterioration of concrete.
5.2 Risk Evaluation—To use this guide effectively, it is
3.2.3.1 Discussion—The term used in this standard guide
necessary to define the level of risk that is acceptable, as this
describes aggregates that undergo chemical reactions with
willdeterminethetypeandcomplexityoftesting(Note1).The
-
hydroxide (OH ) in the pore solution.
risk of deleterious expansion occurring as a result of a failure
3.2.4 non-reactive, adj—used to describe materials that do
to detect deleteriously reactive aggregates can be reduced by
not undergo chemical reactions that subsequently result in
routine testing using petrography, or laboratory expansion
premature deterioration of concrete.
tests, or both.
3.2.4.1 Discussion—Some aggregates with minor amounts
NOTE 1—The level of risk of alkali-silica reaction will depend upon the
of reactive constituents may exhibit the symptoms of alkali-
nature of the project (criticality of the structure and anticipated exposure).
aggregate reaction (AAR) without producing any damage to
The determination of the level of risk is generally associated with the
the concrete; these are termed as non-reactive aggregates.
responsible individual in charge of the design, commonly a representative
of the owner, and for structures designed in accordance with ACI 318, the
4. Summary of Guide
level of acceptable risk would be determined by the licensed design
professional.
4.1 Alkali-aggregate reactions (AAR) occur between the
alkali hydroxides in the pore solution of concrete and certain
5.3 Preventive measures determined by either performance
components found in some aggregates. Two types ofAAR are
testing or the prescriptive approach described in this guide can
recognized depending on the nature of the reactive component:
beexpectedtogenerallyreducetheriskofexpansionasaresult
alkali-silica reaction (ASR) nvolves various types of reactive
of ASR to an acceptable level for conventional structures. For
siliceous (SiO containing) minerals and alkali-carbonate re-
certain critical structures, such as those exposed to continuous
action (ACR) involves certain types of rocks that contain
moisture (for example, hydraulic dams or power plants), in
dolomite [CaMg(CO ) ]. Both types of reaction can result in
which ASR-related expansion cannot be tolerated, more con-
3 2
servative mitigation measures may be warranted.
Available from American Association of State Highway and Transportation
5.4 There are no proven measures for effectively preventing
Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
damaging expansion with alkali carbonate reactive rocks in
http://www.transportation.org.
concrete and such materials need to be avoided by selective
Available from Canadian Standards Association (CSA), 5060 Spectrum Way,
Suite 100, Mississauga, ON, L4W 5N4, Canada, http://www.csa.ca. quarrying.
C1778 − 14
5.5 If an aggregate is identified as potentially deleteriously 6. Procedure
reactive as a result of ASR, and the structure size, class, and
6.1 The flow chart in Fig. 1 shows the general sequence of
exposure condition requires preventive measures, the aggre-
testing and decisions that should be made when evaluating a
gate may be accepted for use together with appropriate
source of aggregate for potential AAR. Prior documented
preventive measures following the prescriptive or performance
satisfactory field performance of the aggregate in concrete is
methods outlined in this guide.
A
The type of reaction only needs to be determined after the concrete prism test if the aggregate being tested is a quarried carbonate that has been identified as being
potentially alkali-carbonate reactive by chemical composition in accordance with test method CSAA23.2-26A.
B
The solid lines show the preferred approach. However, some agencies may want to reduce the amount of testing and accept a higher level of risk and this canbe
achieved by following the direction of the hashed lines.
FIG. 1 Sequence of Laboratory Tests for Evaluating Aggregate Reactivity
C1778 − 14
generally considered to be sufficient for its acceptance in new 7.1.2.1 The aggregate used in the structure surveyed is of
concrete. However, reliance on prior field performance without similar mineralogical composition, as determined by Guide
following the guidance and recommended testing in 7.1 may C295, to that of the aggregate to be used.
not be sufficient to safeguard against damage as a result of
7.1.2.2 Any evidence of damage as a result of AAR; and
AAR in new construction. This is due to the difficulties in
7.1.2.3 The presence, quantity, and composition (if known)
assuring that the materials and mixture proportions used in
of fly ash, slag cement, or other supplementary cementitious
existing structures built 10 to 20 years ago (the time frame
materials.
needed to ensure that a deleterious reaction as a result ofAAR
NOTE 2—Even if signs of deterioration are not observed, cores should
has not occurred) are similar to those being proposed for use
be taken to establish uniformity of materials.
today. In most cases, it will be necessary to perform laboratory
7.1.3 If the results of the field survey indicate that the
tests to determine whether the aggregate is potentially delete-
aggregate is non-reactive, the aggregate may be used in new
riously reactive for the specific concrete mixture to be used.
construction provided that the new concrete is not produced
There are several test methods available for evaluating poten-
with a higher concrete alkali content, a lower SCM replace-
tialAAR;petrographicexamination,determinationofchemical
ment level, or placed in a more aggressive exposure condition
constituents,andmortarbarandconcreteprismexpansiontests
than the structures included in the survey.
are recommended in this guide. If the aggregate is deemed to
be non-reactive, it can be accepted for use in concrete with no 7.1.4 There is a certain level of uncertainty associated with
further consideration of mitigation provided that the other
accepting aggregates solely on the basis of field performance
physical properties of the aggregate render it suitable for use because of difficulties in establishing unequivocally that the
(refer to Specification C33/C33M). If the aggregate is a
materials and proportions used more than 10 to 15 years ago
quarried carbonate, additional tests are required to determine are sufficiently similar to those to be used in new construction.
whether the potential reaction is of the alkali-carbonate or If field performance indicates that an aggregate source is
alkali-silica type. potentially deleteriously reactive, laboratory testing can be
conducted to determine the level of aggregate reactivity and
6.2 Steps for selecting appropriate preventive measures for
evaluate preventive measures. The use of long-term perfor-
ASR follow either a performance-based (Section 8)or
mance is considered to be a reliable method in determining the
prescriptive-based (Section 9) approach. In the performance-
suitability of an aggregate; however, it is often very difficult to
based approach, a potential preventive measure is tested to
acquire the necessary information and background for existing
determine if the measure provides a reduction in expansion
structures.
...
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