ASTM WK43321

    Revision of C1231 / C1231M - 12 Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concrete Cylinders

    (What is a Work Item?)

    Active Standard: C1231 / C1231M - 14

    Developed by Subcommittee: C09.61 | Committee C09 | Contact Staff Manager


    1. Rationale

    The current wording in Section 7.2 requires monitoring of the condition of the elastomeric pads used in the unbonded capping system for testing concrete cylinders and specifies replacement of pads with cracks or splits in excess of 3/8 inch, regardless of depth. A study conducted at NRMCA entitled Tests of Used Unbonded Pad Caps found that pad wear did not contribute to a significant reduction in compressive strength. This ballot item will eliminate the requirement to replace pads that are cracked or split provided that they comply with Section 5.2 and Table 1.


    cap; compressive strength; concrete; concrete test; elastomeric; neoprene; pad cap; rubber; unbonded cap;
    Citing ASTM Standards
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    Work Item Status

    Date Initiated:

    Technical Contact:
    Frances Griffith


    C09 (14-02)

    Ballot Item Approved as C1231/C1231M-2014 and Pending Publication