1、Designation: C641 17Standard Test Method forIron Staining Materials in Lightweight Concrete Aggregates1This standard is issued under the fixed designation C641; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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. Department of Defense.1. Scope*1.1 This test method covers the testing of li
3、ghtweightconcrete aggregates to evaluate the potential degree of stainingfrom iron compounds.1.2 The values stated in SI units are to be regarded as thestandard. The inch-pound values given in parentheses areprovided for information only.1.3 This standard does not purport to address the safetyproble
4、ms associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.1.4 This international standard was developed in accor-dance with internationally recognized pr
5、inciples on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C125 Terminology Relating to
6、Concrete and Concrete Ag-gregatesC330/C330M Specification for Lightweight Aggregates forStructural ConcreteC331/C331M Specification for Lightweight Aggregates forConcrete Masonry UnitsC702/C702M Practice for Reducing Samples of Aggregateto Testing SizeD75/D75M Practice for Sampling AggregatesE11 Spe
7、cification for Woven Wire Test Sieve Cloth and TestSievesE832 Specification for Laboratory Filter Papers3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology C125.4. Significance and Use4.1 This test method evaluates the potential degree ofstainin
8、g attributable to the presence of iron compounds in alightweight aggregate sample primarily by means of a visualclassification method. Such compounds may or may notproduce stains on the surface of the concrete in which theaggregate is incorporated.5. Apparatus5.1 BalanceA balance or scale accurate t
9、o within 0.1 % ofthe test load at any point within the range of use.5.2 Sieves9.5-mm (38-in.) and 600-m (No. 30) sievesconforming to Specification E11.5.3 Filter Papershall comply with Specification E832class E2 with a minimum diameter of 240 mm.5.4 Cheesecloth WrappingTwo thicknesses, reagent grade
10、cheesecloth, approximately 457 mm (18 in.) square is sufficientfor wrapping each sample.5.5 Steam BathAny suitable apparatus that will meet therequirement of the test procedure. Water in the steam bath, andmakeup water, shall be iron-free water or distilled water.NOTE 1An oven top glassware steriliz
11、er made of nonferrous materialsis satisfactory.1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregatesand is the direct responsibility of SubcommitteeC09.21 on Lightweight Aggregates and Concrete.Current edition approved June 15, 2017. Published July 2017
12、. Originallyapproved in 1969. Last previous edition approved in 2009 as C641 09. DOI:10.1520/C0641-17.2For 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
13、Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally reco
14、gnized principles on standardization established 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. Reagents6.1 Purity of ReagentsReagent grade chemicals shall
15、beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.36.2 Purity of WaterUnless otherwise indicated, referencesto water sh
16、all be understood to mean distilled water or water ofequal purity.6.3 Concentration of Reagents:6.3.1 Concentrated Acid and Ammonium HydroxideWhenreagents are specified by name it shall be understood thatconcentrated reagents of the following specific gravity areintended:Hydrochloric acid (HCl) sp g
17、r 1.19Ammonium hydroxide (NH4OH) sp gr 0.906.3.2 Diluted acid is described in terms of the number ofvolumes of the concentrated reagent to be added to a givennumber of volumes of water. Thus HCl (1 + 2) means 1 volumeof HCl (sp gr 1.19) added to 2 volumes of water.7. Sampling7.1 Sample in accordance
18、 with Practice D75/D75M.7.2 After reducing a field sample to an appropriate size inaccordance with Practice C702/C702M, thoroughly dry theaggregate and prepare by sieving material to pass the 9.5-mm(38-in.) sieve and is retained on the 600-m (No. 30) sieve.8. Procedure8.1 Select two portions each we
19、ighing 100 g from theaggregate sample prepared for test.8.2 Crimp the edges of two filter papers to form cup-shapedreceptacles approximately 130 mm (5 in.) in diameter and 60mm (212 in.) in depth. Place one of the 100-g portions in eachfilter cup, spreading to a uniform depth. Fold the sides of thec
20、up to the center and press in that position.8.3 Wrap both portions of the prepared sample, one on topof the other, in cheesecloth. Saturate with distilled water andexpose to steam in the steam bath for 16 h 6 30 min, addingdistilled water as make-up water as required.8.4 Remove from the steam bath,
21、and carefully remove theaggregate from the filter papers. Wash both papers in water,place on a watch glass, and oven dry at a temperature of 110 65 C (230 6 9 F). The insoluble products of the decomposi-tion of iron compounds in the aggregate will be deposited onthe filter paper as red, green, or bl
22、ack stains.8.5 Rate the extent of staining on the filter papers by theVisual Classification Method.8.5.1 Visual Classification MethodEvaluate the extent andintensity of the stains on the filter paper in accordance with thephotographic stain index reference standards shown in Figs.1-5: The photograph
23、ic stain index ranges from No Stain (stainindex = 0) to a Very Heavy Stain (stain index = 100).8.6 When required by Specification C330/C330M andSpecification C331/C331M, follow the procedure of theChemical Analysis Method.3“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-cal
24、Soc., Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see “Reagent Chemicals and Standards,” by JosephRosin, D. Van Nostrand Co., Inc., New York, NY, and the “United StatesPharmacopeia.”Stain Index = 100FIG. 1 Visual Degree of StainingC641 1728.
25、6.1 Chemical Analysis MethodThe iron deposits maybe dissolved from the filter papers by careful application ofHCl from a dropping bottle and rinsing with hot distilled waterfrom a wash bottle. Otherwise, dissolve the iron compound onthe washed and dried filter papers by digesting in HCl (1 + 1)and f
26、iltering out the residue of filter pulp washing thoroughlywith hot water. Precipitate the iron in the filtrate as ferrichydroxide Fe(OH)3by adding NH4OH dropwise to neutralizethe acid using methyl red indicator solution. Redissolve theFe(OH)3precipitate using 10 cm3of HCl (1 + 1) and determinethe ir
27、on quantitatively as Fe2O3by standard titration proce-dures.NOTE 2The iron may be determined by using other standard quanti-tative procedures.Stain Index = 80FIG. 2Stain Index = 60FIG. 3Stain Index = 40FIG. 4C641 1739. Calculation9.1 Calculate the determined Fe2O3to the nearest 0.01 mg(to be reporte
28、d to the nearest 0.1) as follows:Fe2O3, mg/200 g 5 E 3V (1)where:E =Fe2O3equivalent of standard titration solution, mg/mL,V = millilitres of standard titration solution required by thestains from the 200-g sample.10. Report10.1 The report shall include the following:10.1.1 Identification of the samp
29、le,10.1.2 Stain index, as evaluated by the Visual ClassificationMethod, when required, and10.1.3 Iron content as milligrams of Fe2O3per 200 g ofsample evaluated by the Chemical Analysis Method.11. Precision and Bias11.1 PrecisionThe precision of this test method has notyet been determined, but an in
30、terlaboratory testing program isunderway. The precision statements will be included when thedata are compiled and reviewed.11.2 BiasBias for this test method cannot be determinedsince there is no reference standard available for comparison.12. Keywords12.1 iron; lightweight aggregate; stainingSUMMAR
31、Y OF CHANGESCommittee C09 has identified the location of selected changes to this test method since the last issue,C641 09, that may impact the use of this test method. (Approved June 15, 2017.)(1) Revised minimum filter paper size in 5.3.(2) Added tolerances to time in 8.3.(3) Added terminology sec
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35、mmittee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor 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 aboveadd
36、ress 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ Index = 20FIG. 5C641 174
