ASTM WK75808

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

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    Active Standard: C140 / C140M - 20a

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



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


    Results from the Cement and Concrete Reference Laboratory (CCRL) Proficiency Sample Program have indicated that there is considerable scatter with laboratories when performing this calculation. The data has been reviewed, and the scatter in results can be attributed to a few systemic errors that labs have been making: Using the actual length and height of the unit when calculating normalized web area rather than nominal dimensions Using the web area from only one web (rather than all of the webs of the units) in the calculation In addition, it is not clear that laboratories always are totally familiar with the term web, which is not defined within ASTM. This ballot proposes a series of changes to help clarify this calculation with the hopes of assisting labs in performing the calculation properly: Adding a definition for web, Adding calculations in A1.5.2 for web area and 1.5.3 for total minimum web area to be explicit on how those values are calculated, and Adding a note in the calculation section of Annex A1 discussing common errors.

    Citing ASTM Standards
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    Work Item Status

    Date Initiated:

    Technical Contact:
    Craig Walloch


    C15 (21-01)

    On Hold