The purpose of this study is to establish strength estimation method for high strength and mass concrete using non-destructive inspection method. In this study, Experimental studies of non-destructive inspection and concrete core strength for 5 years age are carried out and the following conclusions are drawn. With the proposed estimate equation using single rebound-hummer method in this study, it is judged that the compressive strength of concrete structure can presume. And the analysis shows that the combination of rebound-hummer method and elastic-wave propagation method gives more accurate estimation equations than the single method.
