Reliability Comparison of Schmidt Rebound Hammer as a Non-Destructive Test with Compressive Strength Tests for different Concrete Mix

Abstract

One of the most important concrete properties for structural concrete design or redesign is the compressive strength, it gives information on the characteristics of concrete. This strength measure is obtained through standardized crushing tests on cast cubes, the cubes are produced alongside the construction of concrete elements on site however they are not available for strength testing of existing buildings henc3e the need for non-destructive test methods. Schmidt's Rebound Hammer is a nondestructive test which is used to assess the compressive strength of concrete using rebound index. Surface hardness test was done on different concrete mix and compared with cube compressive strength tests. The changes in one variable explained by the change in a related variable as given by the R-squared are 93.79%, 99.42%, 86.8%, 1% and 98.5% for Mix 1, 2, 3, 4 and 5 respectively. It is noted that for proper result from non-destructive tests, more than one should be implored and the model calibration should be based on actual compressive strength.