228.1R-95: In-Place Methods for Determination of Strength of Concrete
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Note: A newer version of this document exists. This document was replaced by 228.1R-03.
Guidance is provided on the use of methods to estimate the in-place strength of concrete in new and existing construction. The methods include: rebound hammer, penetration resistance, pullout, break-off, ultrasonic pulse velocity, maturity, and cast-in-place cylinder. The principle inherent limitations of each method are reviewed. Procedures are presented for developing the relationship needed to estimate compressive strength from in-place tests are discussed, and statistical techniques to interpret test results are presented. The use of in-place tests for acceptance of concrete is introduced. The appendix provides information on the number of strength levels that should be used to develop the strength relationship and explains a regression analysis procedure that account for error in the independent variable.