1、Designation: C 641 07Standard Test Method forIron Staining Materials in Lightweight Concrete Aggregates1This standard is issued under the fixed designation C 641; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (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 testing of ligh
3、tweightconcrete 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 safetyproblems
4、 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.2. Referenced Documents2.1 ASTM Standards:2C 330 Specification for Lightweight Aggregates for Str
5、uc-tural ConcreteC 331 Specification for Lightweight Aggregates for Con-crete Masonry UnitsC 702 Practice for Reducing Samples of Aggregate toTesting SizeD75 Practice for Sampling AggregatesE11 Specification for Wire Cloth and Sieves for TestingPurposes3. Significance and Use3.1 This test method eva
6、luates the potential degree ofstaining 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.4. Apparatus4.1
7、 BalanceAbalance or scale accurate to within 0.1 % ofthe test load at any point within the range of use.4.2 Sieves 9.5-mm (38-in.) and 600-m (No. 30) sievesconforming to Specification E11.4.3 Filter Paper250 6 10-mm diameter, rapid filtering,high wet bursting strength, quantitative grade white filte
8、r paper.4.4 Cheesecloth WrappingTwo thicknesses, reagent gradecheesecloth, approximately 457 mm (18 in.) square is sufficientfor wrapping each sample.4.5 Steam BathAny suitable apparatus that will meet therequirement of the test procedure. Water in the steam bath, andmakeup water, shall be iron-free
9、 water or distilled water.NOTE 1An oven top glassware sterilizer made of nonferrous materialsis satisfactory.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Comm
10、it-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.35.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled water or water ofequal purity.5.3 Concentration of Reagents:5.3.1 Concentrated Acid and Ammo
11、nium HydroxideWhenreagents are specified by name it shall be understood thatconcentrated reagents of the following specific gravity areintended:Hydrochloric acid (HCl) sp gr 1.19Ammonium hydroxide (NH4OH) sp gr 0.905.3.2 Diluted acid is described in terms of the number ofvolumes of the concentrated
12、reagent to be added to a given1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.21 on Lightweight Aggregates and Concrete.Current edition approved Jan. 1, 2007. Published February 2007. Originallya
13、pproved in 1969. Last previous edition approved in 1998 as C 641 98e1.2For 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
14、 website.3“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-cal 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
15、United StatesPharmacopeia.”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.number of volumes of water. Thus HCl (1 + 2) means 1 volumeof HCl (sp gr 1.19) added to 2 v
16、olumes of water.6. Sampling6.1 Sample in accordance with Practice D75.6.2 After reducing a field sample to an appropriate size inaccordance with Methods C 702, thoroughly dry the aggregateand prepare by sieving material to pass the 9.5-mm (38-in.)sieve and is retained on the 600-m (No. 30) sieve.7.
17、Procedure7.1 Select two portions each weighing 100 g from theaggregate sample prepared for test.7.2 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
18、 a uniform depth. Fold the sides of thecup to the center and press in that position.7.3 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, adding distilledwater as make-up water as required.7
19、4 Remove from the steam bath, 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 fi
20、lter paper as red, green, or black stains.7.5 Rate the extent of staining on the filter papers by theVisual Classification Method.7.5.1 Visual Classification MethodEvaluate the extent andintensity of the stains on the filter paper in accordance with thephotographic stain index reference standards sh
21、own in Figs.1-5: The photographic stain index ranges from No Stain (stainindex = 0) to a Very Heavy Stain (stain index = 100).7.6 When required by Specification C 330 and SpecificationC 331, follow the procedure of the Chemical Analysis Method.7.6.1 Chemical Analysis MethodThe iron deposits maybe di
22、ssolved 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 filtering out the residue of filter pulp washing thorou
23、ghlywith 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 iron quantitatively as Fe2O3by standard titration proce-
24、dures.NOTE 2The iron may be determined by using other standard quanti-tative procedures.8. Calculation8.1 Calculate the determined Fe2O3to the nearest 0.01 mg(to be reported to the nearest 0.1) as follows:Fe2O3, mg/200 g 5 E 3 V (1)where:E =Fe2O3equivalent of standard titration solution, mg/mL,V = m
25、illilitres of standard titration solution required by thestains from the 200-g sample.Stain Index = 100FIG. 1 Visual Degree of StainingC6410729. Report9.1 The report shall include the following:9.1.1 Identification of the sample,9.1.2 Stain index, as evaluated by the Visual ClassificationMethod, whe
26、n required, and9.1.3 Iron content as milligrams of Fe2O3per 200 g ofsample evaluated by the Chemical Analysis Method.10. Precision and Bias10.1 PrecisionThe precision of this test method has notyet been determined, but an interlaboratory testing program isunderway. The precision statements will be i
27、ncluded when thedata are compiled and reviewed.10.2 BiasBias for this test method cannot be determinedsince there is no reference standard available for comparison.Stain Index = 80FIG. 2Stain Index = 60FIG. 3Stain Index = 40FIG. 4C64107311. Keywords11.1 iron; lightweight aggregate; stainingSUMMARY O
28、F CHANGESCommittee C09 has identified the location of selected changes to this test method since the last issue,C64198e1, that may impact the use of this test method. (Approved January 1, 2007)(1) Revised 10.1 and 10.2.ASTM International takes no position respecting the validity of any patent rights
29、 asserted in connection with 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 ti
30、me by the responsible technical 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
31、receive careful consideration 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
32、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 aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).Stain Index = 20FIG. 5C641074
