1、Designation: C 1260 07Standard Test Method forPotential Alkali Reactivity of Aggregates (Mortar-BarMethod)1This standard is issued under the fixed designation C 1260; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 aggregatei
3、n mortar bars.1.2 The values stated in SI units are to be regarded asstandard. The values in inch-pound units are shown in paren-theses, and are for informational purposes only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsi
4、bility 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 section on Reagents.2. Referenced Documents2.1 ASTM Standards:2C 109/C 109M Test Meth
5、od for Compressive Strength ofHydraulic Cement Mortars(Using 2-in. or 50-mm CubeSpecimens)C 125 Terminology Relating to Concrete and ConcreteAggregatesC 127 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Coarse AggregateC 128 Test Method for Density, Relative Density
6、(SpecificGravity), and Absorption of Fine AggregateC 150 Specification for Portland CementC 151 Test Method for Autoclave Expansion of HydraulicCementC 295 Guide for Petrographic Examination of Aggregatesfor ConcreteC 305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plasti
7、c ConsistencyC 490 Practice for Use of Apparatus for the Determinationof Length Change of Hardened Cement Paste, Mortar, andConcreteC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC 670 Practice for Prepari
8、ng Precision and Bias Statementsfor Test Methods for Construction MaterialsC 856 Practice for Petrographic Examination of HardenedConcreteD 1193 Specification for Reagent WaterE11 Specification for Wire Cloth and Sieves for TestingPurposes3. Terminology3.1 Definitions:3.1.1 relative density (OD), na
9、s defined in Test MethodsC 127 or C 128, for coarse and fine aggregates, respectively.3.2 For definitions of other terms relating to concrete oraggregates, see Terminology C 125.4. Significance and Use4.1 This test method provides a means of detecting thepotential of an aggregate intended for use in
10、 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 thatreact slowly or produce expansion late in the reaction. How-ever, it does not evaluate combination
11、s 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 of the cement is not a significant factor inaffecting expansions.4.3 When excessive expansion
12、s (see Appendix X1) areobserved, it is recommended that supplementary informationbe developed to confirm that the expansion is actually due toalkali-silica reaction. Sources of such supplementary informa-tion include: (1) petrographic examination of the aggregate1This test method is under the jurisd
13、iction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.26 on Chemical Reactions.Current edition approved June 1, 2007. Published July 2007. Originally approvedin 1989. Last previous edition approved in 2005 as C 1260 05a.2For referenced AS
14、TM standards, 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 o
15、fthe text.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, United States.(Guide C 295) to determine if known reactive constituents arepresent; (2) examination of the specimens after
16、tests (PracticeC 856) to identify the products of alkali reaction; and (3) whereavailable, field service records can be used in the assessment ofperformance.4.4 When it has been concluded from the results of testsperformed using this test method and supplementary informa-tion that a given aggregate
17、should be considered potentiallydeleteriously reactive, the use of mitigative measures such aslow-alkali portland cement, mineral admixtures, or groundgranulated blast-furnace slag should be evaluated (see lastsentence of 4.1).5. Apparatus5.1 The apparatus shall conform to Specification C 490,except
18、 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 the requirements of PracticeC 305, except that the clearance between the lower end of thepaddle and the bottom of the bowl sh
19、all be 5.1 6 0.3 mm (0.206 0.01 in.).5.4 Tamper and TrowelThe tamper and trowel shall con-form to Test Method C 109/C 109M.5.5 ContainersThe containers shall be of such a naturethat the bars can be totally immersed in either the water or 1NNaOH solution. The containers shall be made of material that
20、can withstand prolonged exposure to 80 C (176 F) and mustbe resistant to a 1N NaOH solution (see Note 1). Thecontainers must be so constructed that when used for storingspecimens, the loss or gain of moisture is prevented bytight-fitting covers, by sealing, or both (see Note 2). The barsin the solut
21、ion must be placed and supported so that thesolution has access to the entire surface of the bar; therefore, itshould be ensured that the specimens do not touch the sides ofthe container or each other. The specimens, if stood upright inthe solution, shall not be supported by the metal gauge stud.NOT
22、E 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, or Water BathA convection oven or water bathwith temperature control maintaining 80.0 6 2.0 C (1
23、76 6 3.6F).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 indicated, referencesto water shall be understood to mean reagent water conforming
24、to Type IV of Specification D 1193.6.3 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 1.0 L of solution. The volume proportion of sodiumhydroxide solution to mortar ba
25、rs 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.6.3.1 WarningBefore using NaOH, review: (1) the safetyprecautions for using NaOH;
26、 (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-tected skin and eyes. Suitable personal protective equipmentshould always be use
27、d. 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 at not less than 20 C (68 F) and not more than 27.5C (81.5 F). The temperature o
28、f the mixing water, and of themoist closet or moist room, shall not vary from 23 C (73.4 F)by more than 1.7 C (3 F).7.2 Maintain the relative humidity of the molding room atnot less than 50 %. The moist closet or room shall conform toSpecification C511.7.3 Maintain the storage oven or water bath in
29、which thespecimens are stored in the containers at a temperature of 80.06 2.0 C (176 6 3.6 F).8. Sampling and Preparation of Test Specimens8.1 Selection of AggregateProcess materials proposed foruse as fine aggregate in concrete as described in the section onPreparation ofAggregate with a minimum of
30、 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 coarse aggregate as proposed for
31、 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 composition that the finer sizes
32、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 Preparation of AggregateGrade all aggr
33、egates towhich this test method is applied in accordance with therequirements given in Table 1. Crush aggregates in whichsufficient quantities of the sizes specified inTable 1 do not existTABLE 1 Grading RequirementsSieve SizeMass, %Passing Retained on4.75 mm (No. 4) 2.36 mm (No. 8) 102.36 mm (No. 8
34、) 1.18 mm (No. 16) 251.18 mm (No. 16) 600 m (No. 30) 25600 m (No. 30) 300 m (No. 50) 25300 m (No. 50) 150 m (No. 100) 15C1260072until the required material has been produced. In the case ofaggregates containing insufficient amounts of one or more ofthe larger sizes listed in Table 1, and if no large
35、r 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 specialnote thereof in the test report. Afte
36、r 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 suchportion individually in a clean co
37、ntainer provided with atight-fitting cover.8.3 Selection and Preparation of Cement:8.3.1 Reference CementUse a portland cement meetingthe requirements of Specification C 150 (Note 3). In addition,the autoclave expansion in Test Method C 151 shall be lessthan 0.20 %.NOTE 3The alkali content of the ce
38、ment has been found to havenegligible (3) or minor (6) 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 SpecimensMake at least three test speci-mens
39、 for each cement-aggregate combination.8.4.2 Preparation of MoldsPrepare the specimen molds inaccordance with the requirements of Practice C 490 except, theinterior surfaces of the mold shall be covered with a releaseagent (see Note 4). A release agent will be acceptable if itserves as a parting age
40、nt without affecting the time of setting ofthe cement and without leaving any residue that will inhibit thepenetration of water into the specimen.NOTE 4TFE-fluorocarbon tape complies with the requirements for amold release agent.8.4.3 Proportioning of MortarProportion the dry materi-als for the test
41、 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 5 2.25 3 D/2.65where:D = relative density (OD)
42、 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 made up byrecombining the portions retained on
43、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 batch of mortar for making three specimens shall b
44、e 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 a water-cement ratio equal to 0.47 by mass (se
45、e 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 C 305.8.4.5 Molding of Test SpecimensMold test specimensw
46、ithin 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 the gauge studs, and along the surfaces of them
47、old 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 each mold in themoist cabinet or room immediat
48、ely 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 theinitial and all subsequent readings to the n
49、earest 0.002 mm.Place the specimens made with each aggregate sample in astorage container with sufficient tap water to totally immersethem. Seal and place the containers in an oven or water bath at80.0 6 2.0 C (176 6 3.6 F) 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 first container have been measured and returnedto the oven or water bath. The time elapsed between removaland return of the specimens to the oven or water bath sha
