REGRESSION EQUATIONS AND VALIDITY OF ULTRA-SONIC, REBOUND AND COMBINED METHODS : Estimation of strength of concrete in structures by non-destructive testing Part 3

Abstract

To estimate strength of concrete in structures non-destructive testing of ultra-sonic, rebound and combined methods are used in this study. From experimental study using full scale model walls regression equations to estimate strength of concrete by these testing methods and allowance of estimations are presented respectively. From field investigations for actual buildings aged 20〜50 years, average value and variation of strength of concrete in structures can be estimated with reasonable accuracy by using regression equations mentioned above and correcting factors as to longer age of concrete obtained from the study. And from statistical study, the numbers of measurements of non-destructive test to estimate strength of concrete required to maintain equivalent accuracy in comparing with the conventional destructive test are proposed.