Non-destructive tests give information about a structures concrete properties. Still, the reliability of evaluating those properties depends on the experience of the profes-sional who carries out the tests and the curves employed to correlate the measured values with the properties of the investigated concrete. The Non-destructive Test methods (NDT) have been used to evaluate concrete strength in many countries, and experimental studies have investigated which method is more reliable and practical. The concrete properties are estimated/ predicted using correlation curves that combine non-destructive test measurements with the compressive strength of concrete established through a laboratory testing program. Typically, the parameters that influence these curves are the water-to-cement ratio, the type of aggregate, the maximum aggregate size, and the type of cement used in the concrete. This paper presents a study on the influence of different parameters on ultrasonic pulse velocity results and rebound hammer methods. It was found that applying multiple regression to data from two types of non-destructive tests provides a more accurate estimate of compressive strength.
Evangelista et al. (Tue,) studied this question.