PROCESS OF IN-PLACE EVALUATION OF CONCRETE STRENGTH

In-place test methods are available that can be used as alternatives t o testing field-cured specimens to evaluate concrete strength in a str ucture. However, in-place test results do not represent the compressiv e strength of concrete directly but are empirically correlated to the compressive strength. Therefore, to use in-place test methods to estim ate the strength of concrete, a preestiablished relationship is requir ed between the in-place test results and standard cylinder test result s. In addition, a statistically based procedure is needed for a reliab le estimate of concrete strength based on the strength relationship an d in-place test results. This paper describes the statistical framewor k for developing the strength relationship and provides a step-by-step procedure to evaluate the characteristic compressive strength of conc rete from in-place test results. Pullout test data are used to illustr ate the use of these computational procedures.