ASTM WK66575

    Revision of C1797 - 17 Standard Specification for Ground Calcium Carbonate and Aggregate Mineral Fillers for use in Hydraulic Cement Concrete

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    Active Standard: C1797 - 17

    Developed by Subcommittee: C09.20 | Committee C09 | Contact Staff Manager



    WK66575


    Keywords

    aggregate mineral filler; ground calcium carbonate; hydraulic cement concrete; limestone; mineral filler; calcium carbonate; EDTA; limestone; magnesium carbonate; titration;;

    Rationale

    ASTM C1797 states, if concrete in service is subjected to sulfate exposure, fillers derived from ground limestone should not be used unless mitigation methods are used. The sulfate resistance of Portland cement can be assessed using ASTM C1012, standard test method for length change of hydraulic-cement mortars exposed to a sulfate solution. However, there is currently no accepted standard for testing the sulfate resistance of mineral fillers. Recent discussions at ACI and ASTM have highlighted the need to develop a test method to evaluate the performance of mineral fillers in contributing to the durability of concrete in a sulfate environment. A modified ASTM C1012 method is utilized in ASTM C311 to evaluate the effectiveness of fly ash or natural pozzolans in contributing to sulfate resistance. Procedure B outlined in section 34 of ASTM C311 details test mixtures that use, the combined quantity of cement plus fly ash or natural pozzolan, by mass, the same as the total cement used in the control mixture. The use of supplementary cementitious materials (SCMs) as a partial replacement for cement is known to improve the durability of concrete. Mineral fillers are not pozzolanic, therefore they should not be incorporated in the test mixes as a cement replacement. In order to evaluate the performance of mineral fillers alone, the cement content of test mixes should be held constant. The proposed method would incorporate mineral fillers as a partial replacement for sand. Test mortars would be prepared by replacing sand with an equal volume of mineral filler. Test mortars prepared using this modified method would be cured and measured according to C1012. By comparing the length change of test mortars with a control mortar, the impact of mineral fillers on the durability of concrete exposed to sulfate environments can be accurately assessed.

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    Work Item Status

    Date Initiated:
    01-11-2019

    Technical Contact:
    Anna Landreville

    Status:
    Draft Under Development