1、Designation: C40/C40M 16 American 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 in
2、dicates 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
3、of the U.S. 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 ot
4、her uses 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 ma
5、y result 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 regula
6、tory limitations 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
7、Aggregate to TestingSizeD75 Practice for Sampling AggregatesD1544 Test Method for Color of Transparent Liquids (Gard-ner Color Scale)3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology C125.4. Significance and Use4.1 This test method is used in making a prelimina
8、rydetermination of the acceptability of fine aggregates withrespect to the requirements of Specification C33 that relate toorganic impurities.4.2 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
9、 test produces a colordarker than the standard color it is advisable to perform the testfor the effect of organic impurities on the strength of mortar inaccordance with Test Method C87.5. Apparatus5.1 BottlesColorless glass or plastic graduated bottles,approximately 240 to 470-mL 8 to 16-oz nominal
10、capacity,equipped with watertight stoppers or caps, not soluble in thespecified reagents. In no case shall 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. Replace bottles when no l
11、ongercolorless due to use.5.2 Standard Color Solution Level75 mL 2.5 oz (U.S.fluid),5.3 Fine Aggregate Level130 mL 4.5 oz (U.S. fluid), and5.4 NaOH Solution Level200 mL 7 oz (U.S. fluid).5.5 Glass Color Standard5.5.1 Glass standard colors shall be used as described inTable 1 of Test Method D1544.NOT
12、E 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 10.2.6. Reagent and Standard Color Solution6.1 Reagent Sodium Hydroxide Solution (3 %)Dissolve 3parts by
13、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 SubcommitteeC09.20 on Normal Weight Aggregates.Current edition approved Dec. 1, 2016. Published J
14、anuary 2017. Originallyapproved in 1921. Last previous edition approved in 2011 as C40/C40M11. DOI:10.1520/C0040_C0040M-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re
15、fer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization establi
16、shed in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16.2 Standard Color SolutionDissolve reagent grade potas-sium dichromate (K2Cr2O7) in concentrated sulfuric
17、acid (sp gr1.84) at the rate of 0.250 g/100 mL of acid. The solution mustbe freshly made for the color comparison using gentle heat ifnecessary to effect solution.7. Sampling7.1 The sample shall be selected in general accordance withPractice D75.8. Test Sample8.1 The test sample shall have a mass of
18、 about approxi-mately 450 g 1 lb and be taken from the larger sample inaccordance with Practice C702.9. Procedure9.1 Fill a glass bottle to the approximately 130-mL 4.5-fluid oz level with the sample of the fine aggregate (seeTerminology C125) to be tested.9.2 Add the sodium hydroxide solution until
19、 the volume ofthe fine aggregate and liquid, indicated after shaking, isapproximately 200 mL 7 fluid oz.9.3 Stopper the bottle, shake vigorously, and then allow tostand for 24 h.10. Determination of Color Value10.1 Standard Color Solution ProcedureAt the end of the24-h standing period, fill a glass
20、bottle to the approximately75-mL 2.5-fluid oz level with the fresh standard colorsolution, prepared not longer than 2 h previously, as prescribedin 6.2. Hold the bottle with the test sample and the bottle withthe standard color solution side-by-side, and compare the colorof light transmitted through
21、 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.10.2 Glass Color Standard ProcedureTo define moreprecisely the col
22、or of the supernatant liquid of the test sample,five glass standard colors shall be used using the followingcolors:Gardner ColorStandard No.Organic Plate No.518211 3 (standard)14 416 5The comparison procedure described in 10.1 shall be used, except that theorganic plate number which is nearest the c
23、olor of the supernatant liquidabove the test specimen shall be reported. When using this procedure, it isnot necessary to prepare the standard color solution.11. Interpretation11.1 When a sample subjected to this procedure produces acolor darker than the standard color, or Organic Plate No. 3(Gardne
24、r 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.12. Precision and Bias12.1 Since this test produces no numerical values, determi
25、-nation of the precision and bias is not possible.13. Keywords13.1 colorimetric test; fine aggregate; organic impuritiesSUMMARY OF CHANGESCommittee C09 has identified the location of selected changes to this standard since the last issue(C40/C40M-11) that may impact the use of this standard. (Approv
26、ed Dec. 1, 2016.)(1) Added Section 3.(2) Revised 5.1 and renumbered remainder of section.(3) Removed Note 1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised t
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