ASTM WK60458

    Revision of C618 - 15 Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete

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    Active Standard: C618 - 19

    Developed by Subcommittee: C09.24 | Committee C09 | Contact Staff Manager



    fly ash; natural pozzolan; pozzolans;;


    Some natural pozzolans have high water requirements but may be used if appropriate concrete mix designs or SCM blends mitigate the high-water requirements. There are natural pozzolans that exceed the water requirements of ASTM C618, but through proper concrete mix designs or blending of the natural pozzolan, the natural pozzolans can be successfully used in concrete mixes. The footnote option has been suggested as a compromise position as opposed to the alternative report only option for water requirements. There is agreement among many committee members that reporting this exception will be more transparent to the end users and specifiers rather than just reporting water requirements. The natural pozzolan must also still pass the Strength Activity Index (SAI) requirements with the higher water content which can provide some additional confidence in the product.

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    Work Item Status

    Date Initiated:

    Technical Contact:
    James Donovan

    Draft Under Development