Evaluation of rebound hammer test as a combined procedure used with drill core testing for evaluation of existing structures

Abstract

Rebound hammer is a non-destructive test method often used to assess the surface hardness of engineering materials. The method is used as a part of the procedure applied to evaluate existing structures. The concrete core tests are usually combined with rebound hammer tests to decrease costs and damage to the structure. Various studies attempted to establish a reliable relationship between the concrete strength and the rebound coefficient. Proposed formulas and correlation coefficients stayed reliable for narrow limits on factors like concrete age, composition, moisture content, etc. Despite the high uncertainty of the raw data the methodology remains in use. This paper presents the evaluation of rebound hammer and drill core test data from 256 different buildings in Antalya, Turkey. With uncontrolled parameters like environmental factors, age, compressive strength of concrete, the rebound hammer test results showed very little correlation with concrete core test results even for the statistically large data set. © RILEM 2013.