1、Designation:C40/C40M16American 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 indicat
2、es 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 of the U.S.
3、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 uses a gla
4、ss 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 result in non-co
5、nformancewith 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 limitations prio
6、r 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 ofAggregate to TestingSi
7、zeD75 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 preliminarydetermination of the acc
8、eptability 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 test produces a colordarke
9、r 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 capacity,equipped with water
10、tight 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 longercolorless due to use.5.2 Stan
11、dard Color Solution Level75 mL 2.5 oz(U.S.fluid),5.3 Fine Aggregate Level130 mL4.5 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.NOTE1A suitable instrument consists of five
12、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 mass of reagent grade sodium hydroxide(NaOH)in
13、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 January 2017.Originallyapproved in 1921.Last previous
14、 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,refer to the standards Document Summary page onthe ASTM websit
15、e.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 Standard Color SolutionDissolve reagent grade potas-sium dichromate(K2Cr2O7)in concentrated sulfuric acid(sp gr1.84)at the rate of 0.250 g/100 mL of acid.The solution mustbe freshly ma
16、de 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 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 solut
