|Q||We’ve just had a laboratory evaluation and one of the test methods examined was ASTM C39. As a footnote to our evaluation they noted that the compression testing machine had bearing blocks that were slightly softer than the 55 HRC mentioned in NOTE 4 of C39. How do we handle this in the future without the cost of hardness testing?
|A||3/24/05 – Response prepared by Terry Egland, Principle, Testing Engineers, Inc.
Rather than address the subject of hardness and what might be a reasonable tolerance, let’s discuss the point of authority that the evaluator is quoting. According to an ASTM document “Form and Style for ASTM Standards” Section A27.1 “Notes in the text shall NOT include mandaroty requirements. Notes are intended to set explanatory material apart from the text itself, either for emphasis or for offering informative suggestions not properly part of the standard.” Therefore, I would suggest that the Subcommittee C09.61 on “Testing Concrete for Strength” feels that a comment on hardness is appropriate but cuts short of mandatory language. The subcommitee has recommended a hardness number of 55 HRC. A slight difference from the recommended would not be a violation of the intent of C39 but a reasonable tolerance is not given.
The same document mentioned above also discusses Footnotes in Section A26.1. “Footnotes referenced in the text are intended ONLY for reference and shall never include any informaton or instructions necessary for the proper application of the method. Table footnotes area a part of the table.” Therefore, again, we see that no mandatory language should be outside of the main text of the document.
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