ASTM C1524-20

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C1524 − 19 C1524 − 20
Standard Test Method for
Water-Extractable Chloride in Aggregate (Soxhlet Method)
This standard is issued under the fixed designation C1524; 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.
1. Scope Scope*
1.1 This test method provides procedures for sampling and analysis of aggregate for water-extractable chloride using a Soxhlet
extractor.
NOTE 1—This test method is to be used when significantly high chloride content has been found in aggregates, concretes, or mortars.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, 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:
C114 Test Methods for Chemical Analysis of Hydraulic Cement
C125 Terminology Relating to Concrete and Concrete Aggregates
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C1152/C1152M Test Method for Acid-Soluble Chloride in Mortar and Concrete
C1218/C1218M Test Method for Water-Soluble Chloride in Mortar and Concrete
D75 Practice for Sampling Aggregates
D1193 Specification for Reagent Water
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
2.2 American Concrete Institute Standard:
ACI 222.1–96 Provisional Standard Test Method for Water-Soluble Chloride Available for Corrosion of Embedded Steel in
Mortar and Concrete Using the Soxhlet Extractor
3. Terminology
3.1 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 Aggregates and is the direct responsibility of Subcommittee C09.69 on
Miscellaneous Tests.
Current edition approved Dec. 15, 2019Dec. 15, 2020. Published January 2020February 2021. Originally approved in 2002. Last previous edition approved in 20102019
as C1524 – 02a (2010), which was withdrawn in January 2019 and reinstated in December 2019. DOI: 10.1520/C1524-19.19. DOI: 10.1520/C1524-20.
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.
Available from American Concrete Institute (ACI), 38800 Country Club Dr., Farmington Hills, MI 48331-3439, http://www.concrete.org.
*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
C1524 − 20
4. Significance and Use
4.1 Water-extractable chloride, when present in sufficient amount, has a potential to initiate or accelerate corrosion of metals, such
as steel, embedded in or contacting a cementitious system, such as mortar, grout, or concrete. This test method is applicable when
aggregates contain a high background of naturally occurring chloride (see ACI 222.1–96 ). Test Method C1152/C1152M
determines acid-soluble chloride and Test Method C1218/C1218M determines water-soluble chloride. Both Test Methods
C1152/C1152M and C1218/C1218M pulverize the sample to a fine powder or fine granular material. The Soxhlet method is
intended to use nonpulverized material. Results with some aggregates have shown that the Soxhlet procedure extracts an extremely
low amount of chloride, with most of it remaining in the rock, and therefore, it is not available for corrosion.
4.2 The Soxhlet extraction apparatus consists of three sections: the boiling flask, which contains reagent water at the beginning
of the test; the extractor, which contains the sample inside a thimble; and, the condenser. The extractor functions by boiling the
water, which condenses and drips on to the sample. When the water attains a fixed height above the sample, the extractor siphons
the water from the thimble back to the boiling flask. The process repeats itself until the test is terminated. (Refer to Fig. 1.)
5. Apparatus
5.1 Sampling Equipment:
FIG. 1 Soxhlet Extraction Apparatus
C1524 − 20
5.1.1 The apparatus required for obtaining aggregate samples is described in Practice D75.
5.2 Sampling Processing Apparatus, the same as in Test Method C1218/C1218M without pulverization.
5.3 Soxhlet Extractor Apparatus, shall have the following minimum size and consist of the following (see Fig. 1).
5.3.1 Reflux-Type Condenser, with a 34/45 mm ground-glass fitting to the extractor, and having a 27 mm inside diameter by a
192 mm body length.
5.3.2 Soxhlet Extraction Tube, with a 34/45 mm ground-glass fitting to the condenser and a 24/40 mm ground-glass fitting to the
boiling flask, for holding sample thimbles 25 mm by 80 mm (diameter by height).
5.3.3 A 250 mL boiling flask with a 24/40- mm ground-glass fitting.
5.3.4 A heating mantel, burner, or hot plate configured for the flask capable of attaining 200 °C.
5.3.5 Suitable Sample Holder, such as a porous extraction thimble having a 25 mm inside diameter and 80 mm external length.
5.4 The apparatus required for the chloride determination step is given in the test method for chloride in Test Methods C114.
5.5 pH Paper, short-range 0.0 – 3.0.
5.6 Drying Oven, of sufficient size, capable of continuously heating at 110 °C 6 5 °C.
5.7 Sieve, 25.0 mm, complying with Specification E11.
6. Reagents
6.1 The reagents required for the chloride determination are given in the test method for chloride of Test Methods C114, and the
Procedure section of Test Method C1218/C1218M.
6.2 Reagent water is either deionized or distilled, conforming to the requirements of Specification D1193 for Type III reagent
water.
7. Sample Preparation
7.1 Preparation:
7.1.1 For Nominal Maximum Aggregate Sizes 25.0 mm or Greater—Use a jaw crusher or hammer, and reduce the sample so that
the particles pass a 25.0 mm sieve and are representative of the sample. Use a sample splitter or use coning and quartering to reduce
the sample to between 200 g and 500 g. Do not crush the sample to a powder. Oven dry the reduced sample at 110 °C 6 5 °C for
2 h.
7.1.2 For Nominal Maximum Aggregate Sizes Less Than 25.0 mm—Use a sample splitter or use coning and quartering to reduce
the sample to between 200 g and 500 g. Do not crush the sample to a powder. Oven dry the reduced sample at 110 °C 6 5 °C for
2 h.
8. Procedure
8.1 Mix and cone the reduced sample three times before sampling each replicate. Obtain a minimum mass of 30.0 g of the sample
by sampling from at least four points, record the mass to the nearest 0.01 g, and transfer it to the porous sample holder of the
Soxhlet extractor. Place at least 200 mL 61 mL of reagent water in the lower flask. Conduct this procedure in triplicate. Make a
blank determination by using the Soxhlet a
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