ASTM C1524 - 20

    Standard Test Method for Water-Extractable Chloride in Aggregate (Soxhlet Method)

    Active Standard ASTM C1524 | Developed by Subcommittee: C09.69

    Book of Standards Volume: 04.02

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    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.)

    FIG. 1 Soxhlet Extraction Apparatus

    Soxhlet Extraction ApparatusSoxhlet Extraction Apparatus

    1. 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 (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    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

    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 Available from American Concrete Institute (ACI), 38800 Country Club Dr., Farmington Hills, MI 48331-3439,

    ICS Code

    ICS Number Code 91.100.30 (Concrete and concrete products)

    UNSPSC Code

    UNSPSC Code 30111800(Aggregates)

    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/C1524-20

    Citation Format

    ASTM C1524-20, Standard Test Method for Water-Extractable Chloride in Aggregate (Soxhlet Method), ASTM International, West Conshohocken, PA, 2020,

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