Correlation between destructive and non-destructive characteristics of pumice and scoria lightweight concretes

This study presents empirical correlations between destructive and non-destructive characteristics of structural lightweight concrete utilizing Medium-K basaltic andesitic pumice and scoria collected from Kelud Volcano, Indonesia. The non-destructive characteristics comprised the rebound number (N) obtained by Schmidt's Hammer test and the pulse velocity (V) obtained by the Ultrasonic Pulse Velocity test. The destructive characteristics were the compressive strength and modulus of elasticity from compressive test, while the tensile strength included splitting tensile strength as well as modulus of rupture from splitting tensile and bending tests. The correlations were determined using simple regression analysis which included linear, quadratic, power and exponential equations. Furthermore, the SonReb method, i.e. multiple regression analysis with linier and power forms of combination of rebound number and pulse velocity, was proposed for comparison. For pumice and scoria lightweight concrete, the simple regression results showed that all destructive characteristics were expressed by the power equation to the rebound number as well as the pulse velocity. This was indicated by coefficients of determination R² which were the largest compared to the other three equations. However, the results of SonReb method with power form, indicated that the coefficients of determination R² were greater than the individual regression results so that their formulas provided more reliable results.