ASTM WK75812

    Revision of C140 / C140M - 20a Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units

    (What is a Work Item?)

    Active Standard: C140 / C140M - 20a

    Developed by Subcommittee: C15.03 | Committee C15 | Contact Staff Manager



    WK75812


    Keywords

    absorption; compressive strength; concrete masonry units; density; equivalent thickness; face shell; moisture content; roof paver; web area; webs; web thickness;;

    Rationale

    In many places in ASTM C140, calculation of properties is based on net volume. This property is calculated using the weights of the specimen determined during absorption testing. For most units, this is appropriate, because the water displacement method in ASTM C140 is the correct way to determine properties of hollow units. For actually solid units, however, this can lead to some confusion. Because of the dry-cast concrete matrix, a unit that is truly solid (where the gross area and net area of the unit) will have a calculated net volume based on absorption testing of slightly less than 100%. This can be troublesome because it is confusing to specifiers, and also not compatible with the building code that considers a solid unit to be solid. This ballot proposes a series of changes to calculations for net volume, net area, and percent solid. In each case, it is proposed to apply a different calculation to units that are truly solid (defined by their gross and net cross-sectional areas in all planes parallel to the bearing surface being equal) and all other units. This is already the way ASTM C140 handles net area, but some clarifying language is included in the ballot. Finally, for net volume, the ballot proposes to define percent solid as 100.0% for units that meet the criteria included for being solid.

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    Work Item Status

    Date Initiated:
    02-08-2021

    Technical Contact:
    Craig Walloch

    Item:
    013

    Ballot:
    C15 (21-01)

    Status:
    Negative Votes Need Resolution