The purpose of this study is to establish strength estimation method for high strength construction concrete whose strength is below 100N/mm2 using non-destructive test. Experimental studies of non-destructive test and concrete core strength are carried out and the following conclusions are drawn in this research. It is confirmed that several multi-regression analysis using combinations of several single non-destructive test results are examined in this study. The analysis shows that the combination of rebound-hummer method and elastic-wave propagation method gives more accurate estimation equations in the concrete strength range of over 60N/mm2 than single rebound-hummer method.
