ASTM C641-23

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Designation: C641 − 17 C641 − 23
Standard Test Method for
Iron Staining Materials in Lightweight Concrete Aggregates
This standard is issued under the fixed designation C641; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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 lightweight concrete aggregates to evaluate the potential degree of staining from iron
compounds.
1.2 The values stated in SI units are to be regarded as the standard. The inch-pound values given in parentheses are provided for
information only.
1.3 This standard does not purport to address all of the safety problems concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate safety and healthsafety, health, and environmental practices and
determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C125 Terminology Relating to Concrete and Concrete Aggregates
C330/C330M Specification for Lightweight Aggregates for Structural Concrete
C331/C331M Specification for Lightweight Aggregates for Concrete Masonry Units
C702/C702M Practice for Reducing Samples of Aggregate to Testing Size
C1761/C1761M Specification for Lightweight Aggregate for Internal Curing of Concrete
D75/D75M Practice for Sampling Aggregates
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
E832 Specification for Laboratory Filter Papers
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology C125.
This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregatesand is the direct responsibility of Subcommittee C09.21 on
Lightweight Aggregates and Concrete.
Current edition approved June 15, 2017June 1, 2023. Published July 2017July 2023. Originally approved in 1969. Last previous edition approved in 20092017 as
C641 – 09.C641 – 17. DOI: 10.1520/C0641-17.10.1520/C0641-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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C641 − 23
4. Significance and Use
4.1 This test method evaluates the potential degree of staining attributable to the presence of iron compounds in a lightweight
aggregate sample primarily by means of a visual classification method. Such compounds may or may not produce stains on the
surface of the concrete in which the aggregate is incorporated.
5. Apparatus
5.1 Balance—A balance or scale accurate to within 0.1 % of the test load at any point within the range of use.
5.2 Sieves—9.5-mm ( ⁄8-in.) and 600-μm (No. 30) sieves conforming to Specification E11.
5.3 Filter Paper—shall comply with Specification E832 class E2 with a minimum diameter of 240 mm.
5.4 Cheesecloth Wrapping—Two thicknesses, reagent grade cheesecloth, approximately 457 mm (18 in.) square is sufficient for
wrapping each sample.
5.5 Steam Bath—Any suitable apparatus that will meet the requirement of the test procedure. Water in the steam bath, and makeup
water, shall be iron-free water or distilled water.
NOTE 1—An oven top glassware sterilizer made of nonferrous materials is satisfactory.
6. Reagents
6.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available.
6.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean distilled water or water of equal
purity.
6.3 Concentration of Reagents:
6.3.1 Concentrated Acid and Ammonium Hydroxide—When reagents are specified by name it shall be understood that
concentrated reagents of the following specific gravity are intended:
Hydrochloric acid (HCl) sp gr 1.19
Ammonium hydroxide (NH OH) sp gr 0.90
6.3.2 Diluted acid is described in terms of the number of volumes of the concentrated reagent to be added to a given number of
volumes of water. Thus HCl (1 + 2) means 1 volume of HCl (sp gr 1.19) added to 2 volumes of water.
7. Sampling
7.1 Sample in accordance with Practice D75/D75M.
7.2 After reducing a field sample to an appropriate size in accordance with Practice C702/C702M, thoroughly dry the aggregate
and prepare by sieving material to pass the 9.5-mm ( ⁄8-in.) sieve and is retained on the 600-μm (No. 30) sieve.
8. Procedure
8.1 Select two portions each weighing 100 g from the aggregate sample prepared fo
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