1、Designation: C1260 14Standard Test Method forPotential Alkali Reactivity of Aggregates (Mortar-BarMethod)1This standard is issued under the fixed designation C1260; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method permits detection, within 16 days, ofthe potential for deleterious alkali-silica reaction of aggregatein m
3、ortar bars.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard. When this test method refers to combined-unitstandards, the selection of the measurement systems is at theusers discretion.1.3 This standard does not purport to add
4、ress all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. A specific precau-tionary statement is given in the sec
5、tion on Reagents.2. Referenced Documents2.1 ASTM Standards:2C109/C109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C125 Terminology Relating to Concrete and Concrete Ag-gregatesC127 Test Method for Density, Relative Density (SpecificGravity), a
6、nd Absorption of Coarse AggregateC128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC150/C150M Specification for Portland CementC151/C151M Test Method for Autoclave Expansion of Hy-draulic CementC295/C295M Guide for Petrographic Examination of Ag-gregat
7、es for ConcreteC305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC490/C490M Practice for Use of Apparatus for the Deter-mination of Length Change of Hardened Cement Paste,Mortar, and ConcreteC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms
8、, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC856 Practice for Petrographic Examination of HardenedConcreteD1193 Specification for Reagent WaterE11 Specification for
9、Woven Wire Test Sieve Cloth and TestSieves3. Terminology3.1 DefinitionsFor definitions of other terms relating toconcrete or aggregates, see Terminology C125.3.1.1 relative density (OD), nas defined in Test MethodsC127 or C128, for coarse and fine aggregates, respectively.4. Significance and Use4.1
10、This test method provides a means of detecting thepotential of an aggregate intended for use in concrete forundergoing alkali-silica reaction resulting in potentially delete-rious internal expansion. It is based on the NBRI AcceleratedTest Method (1-4).3It is especially useful for aggregates thatrea
11、ct slowly or produce expansion late in the reaction.However, it does not evaluate combinations of aggregates withcementitious materials nor are the test conditions representa-tive of those encountered by concrete in service.4.2 Because the specimens are exposed to a NaOH solution,the alkali content
12、of the cement is not a significant factor inaffecting expansions.4.3 When excessive expansions (see Appendix X1) areobserved, it is recommended that supplementary informationbe developed to confirm that the expansion is actually due to1This test method is under the jurisdiction of ASTM Committee C09
13、 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.26 on Chemical Reactions.Current edition approved Aug. 1, 2014. Published August 2014. Originallyapproved in 1989. Last previous edition approved in 2007 as C1260 07. DOI:10.1520/C1260-14.2For referenced ASTM sta
14、ndards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthe t
15、ext.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1alkali-silica reaction. Sources of such supplementary informa-tion include: (1) petrographic examination of the aggre
16、gate(Guide C295/C295M) to determine if known reactive constitu-ents are present; (2) examination of the specimens after tests(Practice C856) to identify the products of alkali reaction; and(3) where available, field service records can be used in theassessment of performance.4.4 When it has been con
17、cluded from the results of testsperformed using this test method and supplementary informa-tion that a given aggregate should be considered potentiallydeleteriously reactive, the use of mitigative measures such aslow-alkali portland cement, mineral admixtures, or groundgranulated blast-furnace slag
18、should be evaluated (see lastsentence of 4.1).5. Apparatus5.1 The apparatus shall conform to Specification C490/C490M, except as follows:5.2 SievesSquare hole, woven-wire cloth sieves, shallconform to Specification E11.5.3 Mixer, Paddle, and Mixing BowlMixer, paddle, andmixing bowl shall conform to
19、the requirements of PracticeC305, except that the clearance between the lower end of thepaddle and the bottom of the bowl shall be 5.1 6 0.3 mm.5.4 Tamper and TrowelThe tamper and trowel shall con-form to Test Method C109/C109M.5.5 ContainersThe containers shall be of such a naturethat the bars can
20、be totally immersed in either the water or 1NNaOH solution. The containers shall be made of material thatcan withstand prolonged exposure to 80C and must beresistant to a 1N NaOH solution (see Note 1). The containersmust be so constructed that when used for storing specimens,the loss or gain of mois
21、ture is prevented by tight-fitting covers,by sealing, or both (see Note 2). The bars in the solution mustbe placed and supported so that the solution has access to theentire surface of the bar; therefore, it should be ensured that thespecimens do not touch the sides of the container or each other.Th
22、e specimens, if stood upright in the solution, shall not besupported by the metal gauge stud.NOTE 1The NaOH solution will corrode glass or metal containers.NOTE 2Some microwave-proof food storage containers made ofpolypropylene or high-density polythylene have been found to be accept-able.5.6 Oven,
23、or Water BathA convection oven or water bathwith temperature control maintaining 80.0 6 2.0C.6. Reagents6.1 Sodium Hydroxide (NaOH)USP or technical grademay be used, provided the Na+and OHconcentrations areshown by chemical analysis to lie between 0.99N and 1.01N.6.2 Purity of WaterUnless otherwise
24、indicated, referencesto water shall be understood to mean reagent water conformingto Type IV of Specification D1193.6.3 Sodium Hydroxide SolutionEach litre of solution shallcontain 40.0 g of NaOH dissolved in 900 mL of water, andshall be diluted with additional distilled or deionized water toobtain
25、1.0 L of solution. The volume proportion of sodiumhydroxide solution to mortar bars in a storage container shallbe 4 6 0.5 volumes of solution to 1 volume of mortar bars. Thevolume of a mortar bar may be taken as 184 mL. Includesufficient test solution to ensure complete immersion of themortar bars.
26、6.3.1 WarningBefore using NaOH, review: (1) the safetyprecautions for using NaOH; (2) first aid for burns; and (3) theemergency response to spills, as described in the manufactur-ers Material Safety Data Sheet or other reliable safety litera-ture. NaOH can cause very severe burns and injury to unpro
27、-tected skin and eyes. Suitable personal protective equipmentshould always be used. These should include full-face shields,rubber aprons, and gloves impervious to NaOH. Gloves shouldbe checked periodically for pin holes.7. Conditioning7.1 Maintain the temperature of the molding room and drymaterials
28、 at not less than 20C and not more than 27.5C. Thetemperature of the mixing water, and of the moist closet ormoist room, shall not vary from 23C by more than 2.0C.7.2 Maintain the relative humidity of the molding room atnot less than 50 %. The moist closet or room shall conform toSpecification C511.
29、7.3 Maintain the storage oven or water bath in which thespecimens are stored in the containers at a temperature of 80.06 2.0C.8. Sampling and Preparation of Test Specimens8.1 Selection of AggregateProcess materials proposed foruse as fine aggregate in concrete as described in the section onPreparati
30、on ofAggregate with a minimum of crushing. Processmaterials proposed for use as coarse aggregate in concrete bycrushing to produce as nearly as practical a graded productfrom which a sample can be obtained. Grade the sample asprescribed in Table 1. The sample shall represent the compo-sition of the
31、coarse aggregate as proposed for use.8.1.1 When a given quarried material is proposed for useboth as coarse and as fine aggregate, test it only by selection ofan appropriate sample crushed to the fine aggregates sizes,unless there is reason to expect that the coarser size fractionshave a different c
32、omposition that the finer sizes and that thesedifferences might significantly affect expansion due to reactionwith the alkalies in cement or from the environment of service.In this case test the coarser size fractions in a manner similarto that employed in testing the fine aggregate sizes.8.2 Prepar
33、ation of AggregateGrade all aggregates towhich this test method is applied in accordance with theTABLE 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 (No. 30) 300 m (No. 50) 25300
34、m (No. 50) 150 m (No. 100) 15C1260 142requirements given in Table 1. Crush aggregates in whichsufficient quantities of the sizes specified in Table 1 do not existuntil the required material has been produced. In the case ofaggregates containing insufficient amounts of one or more ofthe larger sizes
35、listed in Table 1, and if no larger material isavailable for crushing, the first size in which sufficient materialis available shall contain the cumulative percentage of materialdown to that size as determined from the grading specified inTable 1. When such procedures are required, make a specialnot
36、e thereof in the test report. After the aggregate has beenseparated into the various sieve sizes, wash each size with awater spray over the sieve to remove adhering dust and fineparticles from the aggregate. Dry the portions retained on thevarious sieves and, unless used immediately, store each such
37、portion individually in a clean container provided with atight-fitting cover.8.3 Selection and Preparation of Cement:8.3.1 Reference CementUse a portland cement meetingthe requirements of Specification C150/C150M (Note 3). Inaddition, the autoclave expansion inTest Method C151/C151Mshall be less tha
38、n 0.20 %.NOTE 3The alkali content of the cement has been found to havenegligible (3) or minor (5) effects on expansion in this test.8.3.2 Preparation of CementPass cement for use in thistest through an 850-m (No. 20) sieve to remove lumps beforeuse.8.4 Preparation of Test Specimens:8.4.1 Number of S
39、pecimensMake at least three test speci-mens for each cement-aggregate combination.8.4.2 Preparation of MoldsPrepare the specimen molds inaccordance with the requirements of Practice C490/C490Mexcept, the interior surfaces of the mold shall be covered witha release agent (see Note 4).Arelease agent w
40、ill be acceptableif it serves as a parting agent without affecting the time ofsetting of the cement and without leaving any residue that willinhibit the penetration of water into the specimen.NOTE 4TFE-fluorocarbon tape complies with the requirements for amold release agent.8.4.3 Proportioning of Mo
41、rtarProportion the dry materi-als for the test mortar using 1 part of cement to 2.25 parts ofgraded aggregate by mass for aggregates with a relative density(OD) at or above 2.45. For aggregates with a relative density(OD) below 2.45, determine the aggregate proportion asfollows:Aggregate proportion
42、5 2.25 3 D/2.65where:D = relative density (OD) of test aggregate.8.4.3.1 For aggregates with a relative density (OD) equal toor greater than 2.45, the quantities of dry materials to be mixedat one time in the batch of mortar for making three specimensshall be 440 g of cement and 990 g of aggregate m
43、ade up byrecombining the portions retained on the various sieves in thegrading prescribed in Table 1 (8.2). Use a water-cement ratioequal to 0.47 by mass (see Note 5).8.4.3.2 For aggregates with a relative density (OD) less than2.45, the quantities of dry materials to be mixed at one time inthe batc
44、h of mortar for making three specimens shall be 440 gof cement and mass of aggregate shall be 440 g multiplied bythe aggregate proportion determined in 8.4.3. This aggregatemass shall be made up by recombining the portions retained onthe various sieves in the grading prescribed in Table 1 (8.2).Use
45、a water-cement ratio equal to 0.47 by mass (see Note 5).NOTE 5Ruggedness tests indicated that mortar bar expansions wereless variable at a fixed water to cement ratio than when gaged to a constantflow (3).8.4.4 Mixing of MortarMix the mortar in accordance withthe requirements of Practice C305.8.4.5
46、Molding of Test SpecimensMold test specimenswithin a total elapsed time of not more than 2 min and 15 safter completion of the original mixing of the mortar batch. Fillthe molds with two approximately equal layers, each layerbeing compacted with the tamper. Work the mortar into thecorners, around th
47、e gauge studs, and along the surfaces of themold with the tamper until a homogeneous specimen isobtained. After the top layer has been compacted, cut off themortar flush with the top of the mold and smooth the surfacewith a few strokes of the trowel.9. Procedure9.1 Initial Storage and ReadingPlace e
48、ach mold in themoist cabinet or room immediately after molds have beenfilled. The specimens shall remain in the molds for 24 6 2h.Remove the specimens from the molds and, while they arebeing protected from loss of moisture, properly identify andmake an initial comparatory reading. Make and record th
49、einitial and all subsequent readings following the length changemeasurement procedures of Specification C490/C490M. Placethe specimens made with each aggregate sample in a storagecontainer with sufficient tap water to totally immerse them.Thetemperature of the water used to immerse the specimens shallbe 23.0 6 2.0C. Seal and place the containers in an oven orwater bath at 80.0 6 2.0C for a period of 24 h.9.2 Zero ReadingsRemove the containers from the ovenor water bath one at a time. Remove other containers only afterthe bars in the fir
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