1、Designation: C227 10Standard Test Method forPotential Alkali Reactivity of Cement-AggregateCombinations (Mortar-Bar Method)1This standard is issued under the fixed designation C227; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers t
3、he determination of the sus-ceptibility of cement-aggregate combinations to expansivereactions involving hydroxyl ions associated with the alkalies(sodium and potassium) by measurement of the increase (ordecrease) in length of mortar bars containing the combinationduring storage under prescribed con
4、ditions of test.1.2 Alkalies participating in the expansive reactions usuallyare derived from the cement; under some circumstances theymay be derived from other constituents of the concrete or fromexternal sources. Two types of alkali reactivity of aggregatesare recognized: (1) an alkali-silica reac
5、tion involving certainsiliceous rocks, minerals, and natural or artificial glasses and(2) an alkali-carbonate reaction involving dolomite in certaincalcitic dolomites and dolomitic limestones (see DescriptiveNomenclature C294). The method is not recommended as ameans to detect the latter reaction be
6、cause expansions pro-duced in the mortar-bar test by the alkali-carbonate reaction(see Test Method C586) are generally much less than thoseproduced by the alkali-silica reaction for combinations havingequally harmful effects in service.1.3 The values stated in SI units are to be regarded asstandard.
7、 When combined standards are cited, the selection ofmeasurement system is at the users discretion subject to therequirements of the referenced standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of thi
8、s standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C33 Specification for Concrete AggregatesC109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Usi
9、ng 2-in. or 50-mm CubeSpecimens)C289 Test Method for Potential Alkali-Silica Reactivity ofAggregates (Chemical Method)C294 Descriptive Nomenclature for Constituents of Con-crete AggregatesC295 Guide for Petrographic Examination of Aggregatesfor ConcreteC305 Practice for Mechanical Mixing of Hydrauli
10、c CementPastes and Mortars of Plastic ConsistencyC441 Test Method for Effectiveness of Pozzolans orGround Blast-Furnace Slag in Preventing Excessive Ex-pansion of Concrete Due to the Alkali-Silica ReactionC490 Practice for Use of Apparatus for the Determinationof Length Change of Hardened Cement Pas
11、te, Mortar, andConcreteC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC586 Test Method for Potential Alkali Reactivity of Car-bonate Rocks as Concrete Aggregates (Rock-CylinderMethod)C856 Practice for Petr
12、ographic Examination of HardenedConcreteC1437 Test Method for Flow of Hydraulic Cement MortarE11 Specification for Woven Wire Test Sieve Cloth and TestSieves1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of Subcom
13、mitteeC09.26 on Chemical Reactions.Current edition approved Feb. 1, 2010. Published March 2010. Originallyapproved in 1950. Last previous edition approved in 2003 as C22703. DOI:10.1520/C0227-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
14、serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
15、 United States.3. Significance and Use3.1 Data correlating the results of tests performed using thistest method with performance of cement-aggregate combina-tions in concrete in service, results of petrographic examinationof aggregates (Guide C295), and results of tests for potentialreactivity of ag
16、gregates by chemical methods have beenpublished in Test Method C289 and should be consulted inconnection with the use of results of tests performed using thistest method as the basis for conclusions and recommendationsconcerning the use of cement-aggregate combinations in con-crete.3.2 The results o
17、f tests performed using this method furnishinformation on the likelihood that a cement-aggregate combi-nation is potentially capable of harmful alkali-silica reactivitywith consequent deleterious expansion of concrete. Criteria todetermine potential deleterious alkali-silica reactivity ofcement-aggr
18、egate combinations from the results of this testmethod have been given in the Appendix of Specification C33.3.3 Insignificant expansion may result when potentiallydeleteriously reactive siliceous rocks are present in compara-tively high proportion even when a high-alkali cement is used.This may occu
19、r because the alkali-silica reaction products arecharacterized by an alkali to silica ratio that is so low as tominimize uptake of water and swelling, or because of alkalileaching from the bars (see section on containers). Dolomiticaggregates that are deleteriously affected by the alkali-carbonate r
20、eaction when employed as course aggregate inconcrete may not produce notable expansion in this testmethod.Also, significant expansion may occur rarely in the testfor reasons other than alkali-aggregate reaction, particularlythe presence of sulfates in the aggregate that produce a sulfateattack upon
21、the cement paste, ferrous sulfides (pyrite, marca-site, or pyrrhotite) that oxidize and hydrate with the release ofsulfate, and materials such as free lime (CaO) or free magnesia(MgO) in the cement or aggregate that progressively hydrateand carbonate.3.4 When expansions in excess of those given in t
22、heAppendix of Specification C33 are shown in results of testsperformed using this test method, it is strongly recommendedthat supplementary information be developed to confirm thatthe expansion is actually due to alkali reactivity. Sources ofsuch supplementary information include: (1) petrographicex
23、amination of the aggregate to determine if known reactiveconstituents are present; (2) examination of the specimens aftertests to identify the products of alkali reactivity; and (3) tests ofthe aggregate for potential reactivity by chemical methods(Test Method C289).3.5 When it has been concluded fr
24、om the results of testsperformed using this test method and supplementary informa-tion as outlined that a given cement-aggregate combinationshould be considered potentially deleteriously reactive, addi-tional studies may be appropriate to develop information on thepotential reactivity of other combi
25、nations containing the samecement with other aggregates, the same aggregate with othercements, or the same cement-aggregate combination with amineral admixture.4. Apparatus4.1 The apparatus shall conform to Specification C490,except as follows:4.2 SievesSquare hole, woven-wire cloth sieves, shallcon
26、form to Specification E11.4.3 Mixer, Paddle, and Mixing Bowl Mixer, paddle, andmixing bowl shall conform to the requirements of PracticeC305, except that the clearance between the lower end of thepaddle and the bottom of the bowl shall be 5 to 6 mm.4.4 Tamper and TrowelThe tamper and trowel shall co
27、n-form to Test Method C109/C109M.4.5 ContainersCovered containers for storing the testspecimens shall be constructed of material that is resistant tocorrosion under the test conditions. The wall thickness of thecontainer and cover shall be less than 6 mm to reduce theinsulating effect and provide a
28、rapid heat transfer for the initial14-day test period. The cover shall be constructed in a mannerto maintain a tight seal between the cover and top of thecontainer wall (Note 1). The container shall be arranged toprovide every surface of each specimen with approximately anequal exposure to an absorb
29、ent wicking material. The speci-mens shall not be in direct contact with the wicking materialbut every surface shall be within 30 mm or less of the thewicking. A typical arrangement of such a container is shown inFig. 1. The inner sides and the center core of the containers areto be lined with an ab
30、sorbent material, such as blotting or filterpaper, to act as a wick and to ensure that the atmosphere in thecontainer is quickly saturated with water vapor when it issealed after the specimens are placed therein. The wickingliners will extend into the top of the water in the bottom of thecontainer a
31、nd above the tops of the specimens. Make provi-sions to support the bars in a vertical position with the lowerend of the bars approximately 25 mm above the surface of thewater in the containers. The weight of the specimens shall notbe supported on the metal gage studs. A supporting rack shallbe prov
32、ided to ensure that the specimens do not touch thewicking material or each other. The supporting rack shall beconstructed of brass wire or other material that is resistant tocorrosion under the test conditions and shall not act as a vaporbarrier but provide free movement of vapors within thecontaine
33、r. Provisions shall be made to prevent water fromsplashing and dripping onto the specimens (Notes 2-4). Ifrequired to prevent the growth of mold on the wicking, add asuitable fungicide to the water in the container. The containersize and internal arrangement of the specimens and wickingmay be varied
34、 at the users discretion, providing expansion datafor all specimens can be shown to be equivalent to thatdeveloped with the container herein described.NOTE 1This seal may be achieved by a double wrap of vinyl tape 38mm or greater in width, overlaying the lid and container wall along its fullcircumfe
35、rence.NOTE 2The shape and spacing of the center wicking material may bemaintained during the test by the use of rubber bands or hardware cloth.NOTE 3If concern exists for adequately preventing dripping orsplashing, the water should be tested for pH and alkali content.NOTE 4The container described in
36、 4.5 and in Fig. 1 has been shownto produce large and reproducible expansions with cement-aggregatecombinations such as borosilicate glass: high-alkali cement combinationcalled for by Test Method C441. However, recent work, at a fewC227 102laboratories, suggests that the same factors that are respon
37、sible for thesuccess with the Test Method C441 mixtures, that is, high, constant,uniform internal relative humidity, will, under certain testing regimespermitted by this test method, promote leaching of alkali from thespecimens and result in little or no expansion from some knowndeleteriously alkali
38、-reactive aggregate: high-alkali cement combinations.Each laboratory should evaluate its containers with a known deleteriouslyalkali-reactive aggregate (not borosilicate glass which releases alkali) anda high-alkali cement, to establish that the expected level of expansion isobtained. If not, try re
39、moving the wicking to reduce the condensation andleaching. Minimizing the temperature variation within the storage roomand the room in which the bars are read may also reduce condensation onand leaching from the bars.5. Temperature and Humidity5.1 The temperature of the molding room and dry material
40、sshall be maintained at not less than 20 C and not more than27.5 C. The temperature of the mixing water, of the moistcloset or moist room, and of the room in which the measure-ments are made shall not vary from 23 C by more than 2.0 C.5.2 The relative humidity of the molding room shall be notless th
41、an 50 %. The moist closet or room shall conform toSpecification C511.5.3 The storage room in which the specimens in containersare stored shall be maintained at a temperature that shall notvary from 38.0 C by more than 2.0 C.6. Selection and Preparation of Materials6.1 Selection of AggregateMaterials
42、 proposed for use asfine aggregate in concrete shall be processed as described in6.2 with a minimum of crushing. Materials proposed for use ascoarse aggregate in concrete shall be processed by crushing toproduce as nearly as practical a graded product from which asample can be obtained. The sample s
43、hall have the grading asprescribed in 6.2 and be representative of the composition ofthe coarse aggregate as proposed for use.6.1.1 When a given quarried material is proposed for use,both as coarse and as fine aggregate, it will be tested only byselection of an appropriate sample crushed to the fine
44、 aggregatesizes, unless there is reason to expect that the coarser sizefractions have a different composition than the finer sizes andthat these differences might significantly affect expansion dueto reaction with the alkalies in cement. In this case the coarsersize fractions should be tested in a m
45、anner similar to thatemployed in testing the fine aggregate sizes.6.1.2 Coarse aggregate crushed to sand size may giveincreased expansion, owing to the increased surface exposedupon crushing. Therefore, if coarse aggregate tested by thismethod produces an excessive amount of expansion, thematerial s
46、hall not be classed as objectionably reactive withalkali unless tests of concrete specimens confirm the findingsof the tests of the mortar.6.2 Preparation of AggregateFine aggregate shall betested in a grading meeting the requirements of the specifica-tions for the project except that any material r
47、etained on the4.75-mm (No. 4) sieve shall be removed. Fine aggregates beingtested for reasons other than to determine compliance withindividual specifications, and all coarse aggregates to whichthis method is applied shall be graded in accordance with therequirements prescribed in Table 1. Aggregate
48、s in whichsufficient quantities of the sizes specified in Table 1 do not existFIG. 1 Diagram of an Acceptable Assembled ContainerTABLE 1 Grading RequirementsSieve SizeMass %Passing Retained on4.75-mm (No. 4) 2.36-mm (No. 8) 102.36-mm (No. 8) 1.18-mm (No. 16) 251.18-mm (No. 16) 600-m (No. 30) 25600-m
49、 (No. 30) 300-m (No. 50) 25300-m (No. 50) 150-m (No. 100) 15C227 103shall be crushed until the required material has been produced.In the case of aggregates containing insufficient amounts of oneor more of the larger sizes listed in Table 1, and if no largermaterial is available for crushing, the first size in whichsufficient material is available shall contain the cumulativepercentage of material down to that size as determined from thegrading specified in Table 1. When such procedures arerequired, special note shall be made thereof in the test report.After
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