1、Designation: C40/C40M 11American Association StateHighway and Transportation Officials StandardAASHTO No.: T 21Standard Test Method forOrganic Impurities in Fine Aggregates for Concrete1This standard is issued under the fixed designation C40/C40M; the number immediately following the designation ind
2、icates the year oforiginal adoption or, in the case of revision, the 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 o
3、f the Department of Defense.1. Scope1.1 This test method covers two procedures for an approxi-mate determination of the presence of injurious organic impu-rities in fine aggregates that are to be used in hydraulic cementmortar or concrete. One procedure uses a standard colorsolution and the other us
4、es a glass color standard.1.2 The values stated in either SI units or inch-pound unitsare 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 resu
5、lt in non-conformancewith the standard.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 determine the applica-bility of regulatory l
6、imitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C33 Specification for Concrete AggregatesC87 Test Method for Effect of Organic Impurities in FineAggregate on Strength of MortarC125 Terminology Relating to Concrete and Concrete Ag-gregatesC702 Practice for Reducing Samples of Aggre
7、gate to Test-ing SizeD75 Practice for Sampling AggregatesD1544 Test Method for Color of Transparent Liquids(Gardner Color Scale)3. Significance and Use3.1 This test method is used in making a preliminarydetermination of the acceptability of fine aggregates withrespect to the requirements of Specific
8、ation C33 that relate toorganic impurities.3.2 The principal value of this test method is to furnish awarning that injurious amounts of organic impurities may bepresent. When a sample subjected to this test produces a colordarker than the standard color it is advisable to perform the testfor the eff
9、ect of organic impurities on the strength of mortar inaccordance with Test Method C87.4. Apparatus4.1 Glass BottlesColorless glass graduated bottles, ap-proximately 240 to 470-mL 8 to 16-oz nominal capacity,equipped with watertight stoppers or caps, not soluble in thespecified reagents. In no case s
10、hall the maximum outsidethickness of the bottles, measured along the line of sight usedfor the color comparison, be greater than 63.5 mm 2.5 in. orless than 38.1 mm 1.5 in. The graduations on the bottles shallbe in millilitres, or ounces (U.S. fluid), except that unmarkedbottles may be calibrated an
11、d scribed with graduations by theuser. In such case, graduation marks are required at only threepoints as follows:4.1.1 Standard Color Solution Level75 mL 2.5 oz (U.S.fluid),4.1.2 Fine Aggregate Level130 mL 4.5 oz (U.S. fluid),and4.1.3 NaOH Solution Level200 mL 7 oz (U.S. fluid).4.2 Glass Color Stan
12、dard4.2.1 Glass standard colors shall be used as described inTable 1 of Test Method D1544.NOTE 1A suitable instrument consists of five glass color standardsmounted in a plastic holder. Only the glass identified as Gardner ColorStandard No. 11 is to be used as the Glass Color Standard in 9.2.5. Reage
13、nt and Standard Color Solution5.1 Reagent Sodium Hydroxide Solution (3 %)Dissolve 3parts by mass of reagent grade sodium hydroxide (NaOH) in 97parts of water.1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of Subco
14、mmitteeC09.20 on Normal Weight Aggregates.Current edition approved April 1, 2011. Published June 2011. Originallyapproved in 1921. Last previous edition approved in 2004 as C4004. DOI:10.1520/C0040_C0040M-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custome
15、r Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Standard Color SolutionDissolve re
16、agent grade po-tassium dichromate (K2Cr2O7) in concentrated sulfuric acid (spgr 1.84) at the rate of 0.250 g/100 mL of acid. The solutionmust be freshly made for the color comparison using gentleheat if necessary to effect solution.6. Sampling6.1 The sample shall be selected in general accordance wi
17、thPractice D75.7. Test Sample7.1 The test sample shall have a mass of about approxi-mately 450 g 1 lb and be taken from the larger sample inaccordance with Practice C702.8. Procedure8.1 Fill a glass bottle to the approximately 130-mL 4.5-fluid oz level with the sample of the fine aggregate (seeTermi
18、nology C125) to be tested.8.2 Add the sodium hydroxide solution until the volume ofthe fine aggregate and liquid, indicated after shaking, isapproximately 200 mL 7 fluid oz.8.3 Stopper the bottle, shake vigorously, and then allow tostand for 24 h.9. Determination of Color Value9.1 Standard Color Sol
19、ution ProcedureAt the end of the24-h standing period, fill a glass bottle to the approximately75-mL 2.5-fluid oz level with the fresh standard colorsolution, prepared not longer than 2 h previously, as prescribedin 5.2. Hold the bottle with the test sample and the bottle withthe standard color solut
20、ion side-by-side, and compare the colorof light transmitted through the supernatant liquid above thesample with the color of light transmitted through the standardcolor solution. Record whether the color of the supernatantliquid is lighter, darker, or equal to the color of the standardcolor solution
21、.9.2 Glass Color Standard ProcedureTo define more pre-cisely the color of the supernatant liquid of the test sample, fiveglass standard colors shall be used using the following colors:Gardner ColorStandard No.Organic Plate No.518211 3 (standard)14 416 5The comparison procedure described in 9.1 shall
22、 be used, except that the or-ganic plate number which is nearest the color of the supernatant liquid abovethe test specimen shall be reported. When using this procedure, it is not neces-sary to prepare the standard color solution.10. Interpretation10.1 When a sample subjected to this procedure produ
23、ces acolor darker than the standard color, or Organic Plate No. 3(Gardner Color Standard No. 11), the fine aggregate under testshall be considered to possibly contain injurious organicimpurities. It is advisable to perform further tests beforeapproving the fine aggregate for use in concrete.11. Prec
24、ision and Bias11.1 Since this test produces no numerical values, determi-nation of the precision and bias is not possible.12. Keywords12.1 colorimetric test; fine aggregate; organic impuritiesASTM International takes no position respecting the validity of any patent rights asserted in connection wit
25、h any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible techn
26、ical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful considerati
27、on at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Har
28、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).C40/C40M 112
