1、Designation: C87/C87M 10Standard Test Method forEffect of Organic Impurities in Fine Aggregate on Strengthof Mortar1This standard is issued under the fixed designation C87/C87M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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 the d
3、etermination of the effecton mortar strength of the organic impurities in fine aggregate,whose presence is indicated using Test Method C40. Compari-son is made between compressive strengths of mortar madewith washed and unwashed fine aggregate.1.2 The values stated in either SI units or inch-pound u
4、nitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard. Some values have only SI units because the
5、inch-pound equivalents are not used in the practice.NOTE 1Sieve size is identified by its standard designation in Speci-fication E11. The alternative designation given in parentheses is forinformation only and does not represent a different standard sieve size1.3 This standard does not purport to ad
6、dress 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.(WarningFreshhydraulic cementitous mixtures are caustic
7、 and may causechemical burns to exposed skin and tissue upon prolongedexposure.)22. Referenced Documents2.1 ASTM Standards:3C33 Specification for Concrete AggregatesC40 Test Method for Organic Impurities in Fine Aggregatesfor ConcreteC109/C109M Test Method for Compressive Strength ofHydraulic Cement
8、 Mortars (Using 2-in. or 50-mm CubeSpecimens)C128 Test Method for Density, Relative Density (SpecificGravity), and Absorption of Fine AggregateC150 Specification for Portland CementC230/C230M Specification for Flow Table for Use in Testsof Hydraulic CementC305 Practice for Mechanical Mixing of Hydra
9、ulic CementPastes and Mortars of Plastic ConsistencyC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC702 P
10、ractice for Reducing Samples of Aggregate to Test-ing SizeD75 Practice for Sampling AggregatesD3665 Practice for Random Sampling of Construction Ma-terialsE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3. Summary of Test Method3.1 A portion of the fine aggregate that produced a colo
11、rdarker than the standard in Test Method C40 is used to preparemortar cube specimens. A separate portion of the same fineaggregate is washed in sodium hydroxide solution to removethe organic impurities that caused the failing result when testedin accordance with Test Method C40, and that washed fine
12、aggregate is used to prepare another set of mortar cubespecimens.3.2 After curing for a stated period, the compressivestrengths of the two sets of cube specimens are determined andcompared.1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the
13、 direct responsibility of SubcommitteeC09.20 on Normal Weight Aggregates.Current edition approved Dec. 15, 2010. Published January 2011. Originallyapproved in 1931. Last previous edition approved in 2005 as C8705. DOI:10.1520/C0087_C0087M-10.2See section on Safety Precautions, Manual of Aggregate an
14、d Concrete Testing,Annual Book of ASTM Standards, Vol 04.02.3For referenced ASTM 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.1
15、*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.4. Significance and Use4.1 This test method is of significance in making a finaldetermination of the acceptability of fi
16、ne aggregates withrespect to the requirements of Specification C33 concerningorganic impurities.4.2 This test method is applicable to those samples which,when tested in accordance with Test Method C40, haveproduced a supernatant liquid with a color darker than standardcolor plate No. 3 or color solu
17、tion.4.3 Many specifications provide for the acceptance of fineaggregate producing a darker color in the Test Method C40test, when testing by this test method indicates the strength ofthe mortar cubes prepared with the unwashed fine aggregate iscomparable to the strength of mortar cubes made with th
18、ewashed fine aggregate.5. Apparatus5.1 Flow Table, Flow Mold, and Caliper, as described inSpecification C230/C230M.5.2 Tamper, Trowel, Cube Molds, and Testing Machine,asdescribed in Test Method C109/C109M.5.3 Mixer, Bowl, and Paddle, as described in Practice C305.5.4 Curing Apparatus, as described i
19、n Specification C511.5.5 pH Paper, 014.5.6 pH Meter, capable of reading to 0.1 pH units or better.6. Reagents and Materials6.1 Portland cement shall be Type I or Type II, meeting therequirements of Specification C150.6.2 Sodium Hydroxide Solution (3 %)Dissolve 3 parts bymass of sodium hydroxide (NaO
20、H) in 97 parts water.6.3 PhenolphthaleinDissolve1gofreagent grade phe-nolphthalein in 1 L of 95 % reagent grade ethyl alcohol.7. Sampling and Sample Preparation7.1 If sufficient material remains from the sample used fortesting in accordance with Test Method C40, use this materialfor the tests descri
21、bed in this test method. If there is insufficientmaterial remaining, obtain another field sample from the samesource in accordance with Practice D75 and Practice D3665.NOTE 2At least 20 kg of fine aggregate should be available for thetesting described herein.7.2 If the fine aggregate contains partic
22、les coarser than the4.75-mm (No.4) sieve, remove the coarser particles by sievingon the 4.75-mm (No.4) sieve, so that when the particles aremixed in the designated mixer, there will be no damage to themixer or crushing of the fine aggregate particles. Determine thepercentage of the sample removed. (
23、WarningThe clearancesbetween the paddle and the bowl specified in Practice C305 aresuitable when using the mortar made with graded standardsand. To permit the mixer to operate freely and to avoid seriousdamage to the paddle and bowl when coarser aggregates areused, it may be necessary to set the cle
24、arance adjustmentbracket to provide greater clearances than specified. A clear-ance of approximately 4.0 mm is required in Practice C305;aclearance of approximately 5.0 mm has been found to besatisfactory for this method when used with fine aggregatefrom which the material retained on the 4.75-mm (N
25、o. 4) sievehas been removed.)7.3 Split the fine aggregate to be used for these tests intotwo approximately equal portions, using the procedure de-scribed in Practice C702. Set one portion aside to be used in theunwashed condition. The second portion is to be washed beforeuse.7.4 Preparing Washed Fin
26、e Aggregate:7.4.1 Perform the washing and rinsing of the fine aggregatewith care to minimize the loss of fines, so that the aggregateafter washing and rinsing has a fineness modulus within 0.10 ofthat of the unwashed aggregate.7.4.2 Establishing a Standard for Thoroughness ofRinsingPlace a small amo
27、unt of the water to be used forwashing and rinsing in a clean, clear container, and determinethe pH of the water by use of pH paper, pH meter, or add a dropof phenolphthalein to the wash water and retain for latercomparison.7.4.3 Washing the AggregatePlace sufficient quantity offine aggregate for th
28、ree batches in a suitable container, floodwith the sodium hydroxide solution, and agitate thoroughlywith a spoon or trowel. At the end of the washing and afterallowing to stand for fines to settle, siphon off as much of thesodium hydroxide solution as possible, without removing anyof the aggregate f
29、ines.7.4.4 Rinsing the Aggregate Add a large quantity of waterto the washed aggregate, agitate, allow to stand for fines tosettle, and then siphon off the rinse water. Repeat this operationseveral times, until the water used for rinsing has a pH equal toor lower than the pH of the water prior to con
30、tact with the fineaggregate. If phenolphthalein was used as an indicator, thecolor of the wash water is to be equal or lighter in color thanthe solution prepared in 7.4.2.7.4.5 Verifying Removal of Organic ImpuritiesRepeat theTest Method C40 procedure to determine if the washing hasremoved sufficien
31、t organic impurities to produce a satisfactoryresult (color lighter than the standard). If the fine aggregatecontinues to produce an unsatisfactory result (color darker thanthe standard), repeat the washing and rinsing procedure (de-scribed in 7.4.3 and 7.4.4) as many times as necessary until asatis
32、factory result is obtained by Test Method C40.8. Procedure8.1 Number of Test BatchesPrepare three batches ofmortar using the washed aggregate and three batches of mortarusing the unwashed aggregate, on the same day. Mix thebatches, alternating between the washed and unwashed aggre-gate.8.2 Fine Aggr
33、egateFor both the washed and the un-washed fine aggregates, bring the portions of fine aggregate tothe saturated surface dry condition as described in Test MethodC128. Prepare a quantity of aggregate of known mass (theaggregate specimen) that is slightly more than needed toproduce a single batch of
34、the desired consistency.8.2.1 Optionally, if the absorption has been determined inaccordance with Test Method C128, prepare the aggregate fortest by adding to a known mass of dry aggregate the amount ofC87/C87M 102water it will absorb, mixing thoroughly, and permitting theaggregate to stand in a cov
35、ered pan for 30 min before use.8.3 Preparation of MortarPrepare the mortar in a me-chanical mixer in accordance with the procedure for mixingmortars described in Practice C305, as modified below.8.3.1 Use water and cement in quantities that will yield awater-cement ratio of 0.6 by mass (See Note 3).
36、 The mixingwater shall be at a temperature of 23.0 6 2.0 C 73.5 6 3.5F. The mortar shall be proportioned to produce a consistencyof 100 6 5 % as determined by the Section on Flow Test (see8.4.1).NOTE 3It has been found that 600 g of cement and 360 mL of waterwill usually be adequate for a 6-cube bat
37、ch. The flow is adjusted by thequantity of fine aggregate added to the mixture.8.3.2 After placing all the mixing water in the bowl, add thecement to the water. Start the mixer and mix at the slow speed(140 65 r/min) for 30 s. While still mixing at slow speed overa 30-s period, add a measured quanti
38、ty of aggregate estimatedto provide the proper consistency.NOTE 4The quantity of aggregate used may be determined bysubtracting from a known quantity of prepared aggregate the mass of theportion remaining after mixing.8.3.3 Stop the mixer, change to medium speed (285 6 10r/min), and mix for 30 s.8.3
39、.4 Stop the mixer and let the mortar stand for 1.5 min.During the first 15 s of this interval, quickly scrape down intothe batch any mortar that may have collected on the side of thebowl, then for the remainder of this interval, cover the bowlwith the lid.8.3.5 Finish by mixing for 1 min at medium s
40、peed. If theflow appears to be too high during the first 30 s of this period,stop the mixer briefly, add additional fine aggregate, and thencomplete the final 30 s of mixing.8.3.6 In any case requiring a remixing interval, any mortaradhering to the side of the bowl shall be quickly scraped downinto
41、the batch with the scraper prior to remixing.8.3.7 Make a determination of the flow.8.4 Flow Test:8.4.1 Carefully wipe the flow table clean. Dry the surfaceand place the flow mold at the center. Immediately aftercompleting the mixing operation, place a layer of mortarapproximately 25 mm 1 in. in thi
42、ckness in the mold and tamp20 times with the tamper. The tamping pressure shall be justsufficient to ensure uniform filling of the mold. Slightly overfillthe mold with mortar and tamp as specified for the first layer.Cut off the mortar to a plane surface, flush with the top of themold, by drawing th
43、e straight edge of the trowel (held nearlyperpendicular to the mold) with a sawing motion across the topof the mold. Wipe the table top clean and dry, being especiallycareful to remove any water from around the edge of the flowmold. Lift the mold away from the mortar 1 min aftercompleting the mixing
44、 operation. Immediately drop the tablethrough a height of 12.7 mm 0.5 in. ten times in 6 s. The flowis the resulting increase in average diameter of the mortarspecimen, measured on at least four diameters at approxi-mately equal angles, expressed as a percentage of the originaldiameter.8.4.2 Should
45、the flow be too great, return the mortar to themixing vessel, add additional fine aggregate, mix for 30 s atmedium speed, and make another determination of the flow. Ifmore than two trials must be made to obtain a flow of 100 65 %, consider the mortar as a trial mortar, and prepare a newbatch.8.4.3
46、If the mortar is too dry, discard the batch and preparea new batch starting with a smaller quantity of fine aggregate.8.4.4 Determine the quantity of fine aggregate used bysubtracting the mass of the portion remaining from the originalmass of the aggregate specimen.8.5 Molding Mortar CubesImmediatel
47、y followingcompletion of a flow test that indicates acceptable consistency,return the mortar from the flow table to the mixing bowl,scrape down the bowl, and then remix the entire batch for 15s at medium speed. Upon completion of mixing, shake theexcess mortar from the paddle into the bowl. Mold one
48、 set(three cubes) from each batch, in accordance with Test MethodC109/C109M.8.6 Curing and Testing Mortar CubesStore the test speci-mens in a moist cabinet or moist room maintained at atemperature of 23.0 6 2.0 C 73.5 6 3.5 F and relativehumidity not less than 95 % for 24 612 h. Additional curingsha
49、ll be by immersion in saturated lime water maintained at atemperature of 23.0 6 2.0 C 73.5 6 3.5 F. Determine thecompressive strength of the cubes at 7 days in accordance withTest Method C109/C109M.9. Calculation and Report9.1 Calculate the compressive strength of each specimen bydividing the maximum load it carried during the test by thecross-sectional area. Average the strengths of the three speci-mens from each batch. Calculate three strength ratios bydividing the average strength for a batch containing unwashedfine aggregate by the average str
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