1、Designation: C 87 05Standard Test Method forEffect of Organic Impurities in Fine Aggregate on Strengthof Mortar1This standard is issued under the fixed designation C 87; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) 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 determin
3、ation 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 SI values shown are to be regarded as the standard.The
4、inch-pound values shown in parentheses are provided forinformation purposes only.1.3 This standard does not purport to address 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 de
5、termine the applica-bility of regulatory limitations prior to use.(WarningFreshhydraulic cementitous mixtures are caustic and may causechemical burns to exposed skin and tissue upon prolongedexposure.)22. Referenced Documents2.1 ASTM Standards:3C33 Specification for Concrete AggregatesC40 Test Metho
6、d for Organic Impurities in Fine Aggre-gates for ConcreteC 109/C 109M Test Method for Compressive Strength ofHydraulic Cement Mortars (Using 2-in. or 50-mm CubeSpecimens)C 128 Test Method for Density, Relative Density, (SpecificGravity), and Absorption of Fine AggregateC 150 Specification for Portla
7、nd CementC 230 Specification for Flow Table for Use in Tests ofHydraulic CementC 305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cem
8、ents and ConcretesC 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC 702 Practice for Reducing Samples of Aggregate toTesting SizeD75 Practice for Sampling AggregatesD 3665 Practice for Random Sampling of ConstructionMaterials3. Significance and Us
9、e3.1 This test method is of significance in making a finaldetermination of the acceptability of fine aggregates withrespect to the requirements of Specification C33concerningorganic impurities.3.2 This test method is applicable to those samples which,when tested in accordance with Test Method C40, h
10、aveproduced a supernatant liquid with a color darker than standardcolor plate No. 3 or color solution.3.3 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 pr
11、epared with the unwashed fine aggregate iscomparable to the strength of mortar cubes made with thewashed fine aggregate.4. Summary of Test Method4.1 A portion of the fine aggregate that produced a colordarker than the standard in Test Method C40is used to preparemortar cube specimens. A separate por
12、tion 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 fineaggregate is used to prepare another set of mortar cubespecimens.1This test method is under the juri
13、sdiction of ASTM Committee C09 onConcretes and Concrete Aggregates and is the direct responsibility of Subcommit-tee C09.20 on Normal Weight Aggregates.Current edition approved July 1, 2005. Published July 2005. Originally approvedin 1931. Last previous edition approved in 2004 as C 87 04.2See secti
14、on on Safety Precautions, Manual of Aggregate and 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 stan
15、dards 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, United States.4.2 After curing for a stated period, the compressivestrengths of the tw
16、o sets of cube specimens are determined andcompared.5. Apparatus5.1 Flow Table, Flow Mold, and Caliper, as described inSpecification C 230.5.2 Tamper, Trowel, Cube Molds, and Testing Machine,asdescribed in Test Method C 109/C 109M.5.3 Mixer, Bowl, and Paddle, as described in PracticeC 305.5.4 Curing
17、 Apparatus, as described in 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 C 150.6.2 Sodium Hydroxide Solution (3 %)Dissolve 3 parts byma
18、ss of sodium hydroxide (NaOH) 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 m
19、aterialfor the tests described in this test method. If there is insufficientmaterial remaining, obtain another field sample from the samesource in accordance with Practice D75and Practice D 3665.NOTE 1At least 20 kg of fine aggregate should be available for thetesting described herein.7.2 If the fin
20、e aggregate contains particles 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 thepercenta
21、ge of the sample removed. (WarningThe clearancesbetween the paddle and the bowl specified in Practice C 305are suitable 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
22、 be necessary to set the clearance adjustmentbracket to provide greater clearances than specified. A clear-ance of approximately 4.0 mm is required in Practice C 305;aclearance of approximately 5.0 mm has been found to besatisfactory for this method when used with fine aggregatefrom which the materi
23、al retained on the 4.75-mm (No. 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 C 702. Set one portion aside to be used inthe unwashed condition. The second portion is to be washedbefor
24、e use.7.4 Preparing Washed Fine 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 Thoroughn
25、ess ofRinsingPlace a small amount 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 qu
26、antity offine aggregate for three 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
27、removing anyof the aggregate fines.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 th
28、e pH of the water prior to contact 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 C40procedure to determine if the
29、 washing hasremoved sufficient 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 ti
30、mes as necessary until asatisfactory 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 unwa
31、shed aggre-gate.8.2 Fine AggregateFor both the washed and the un-washed fine aggregates, bring the portions of fine aggregate tothe saturated surface dry condition as described in Test MethodC 128. Prepare a quantity of aggregate of known mass (theaggregate specimen) that is slightly more than neede
32、d toproduce a single batch of the desired consistency.8.2.1 Optionally, if the absorption has been determined inaccordance with Test Method C 128, prepare the aggregate fortest by adding to a known mass of dry aggregate the amount ofwater it will absorb, mixing thoroughly, and permitting theaggregat
33、e to stand in a covered 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 C 305, as modified below.8.3.1 Use water and cement in quantities that will yield awater-cement ratio of 0.6 b
34、y mass (See Note 2). 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 2It has been found that 600 g of cement and 360 mL of waterwill usually be ade
35、quate for a 6-cube batch. The flow is adjusted by theC87052quantity 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 p
36、eriod, add a measured quantity of aggregate estimatedto provide the proper consistency.NOTE 3The 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 10
37、r/min), and mix for 30 s.8.3.4 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
38、mixing for 1 min at medium speed. 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
39、be quickly scraped downinto 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 mortarappr
40、oximately 25 mm (1 in.) in thickness 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
41、 top of themold, by drawing the 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
42、min aftercompleting the mixing 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 th
43、e originaldiameter.8.4.2 Should 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 morta
44、r, and prepare a newbatch.8.4.3 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.
45、5 Molding Mortar CubesImmediately 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 th
46、e paddle into the bowl. Mold one set(three cubes) from each batch, in accordance with Test MethodC 109/C 109M.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
47、% for 24 612 h. Additional curingshall 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 C 109/C 109M.9. Calculation and Report9.1 Calculate the compressive strengt
48、h 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 strength f
49、or the corresponding (inrespective order of mixing) batch containing washed fineaggregate.9.2 Report the average of the three ratios, expressed as apercentage (to the nearest 1 %), as the relative strength for thefine aggregate under test.9.3 If the fine aggregate was sieved to remove particlescoarser than the 4.75 mm (No. 4) sieve (as described in 7.2), sostate in the report and indicate the quantity of material removedas a percentage of the original sample mass.10. Precision and Bias10.1 The following precision statement is applicable when atest result is t
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