Estimating In Situ Compressive Strength of Existing Concrete Structures

Abstract

An upper-bound and lower-bound approach using a combination of the rebound hammer test or Windsor probe test and ultrasonic pulse velocity test or core test for estimating in situ compressive strength of existing concrete structures is presented. A bias factor for each of the nondestructive tests and core test was introduced to account for the overestimation of characteristic in situ compressive strength by rebound hammer test and Windsor probe test and underestimation of characteristic in situ compressive strength by ultrasonic pulse velocity test and core test. In situ concrete testing results of 34 existing concrete structures aged 4–73 years were analyzed to obtain a range of each of the bias factors. Illustrative examples using this upper-bound and lower-bound approach for estimating characteristic in situ compressive strength of existing concrete structures are presented.