응력파 기반 비파괴 검사법을 이용한 콘크리트 슬래브의 압축강도 추정 및 공기량영향에 관한 실험적 연구

Abstract

This research is focused on predicting concrete compressive strength and the influence of Air-contents of concrete slab using Impact Echo (IE) method, Spectral Analysis of Surface Wave(SASW) method and Free-Free Resonance(FFR) test, which are one of the Non-destructive Test (NDT) methods. The method for predicting the strength of concrete slab are derived from the relationship between compressive strength and stress wave velocity. Furthermore, the influence of air ratio to the stress wave velocity and the compressive strength has been analyzed using specimens that have been prepared based on the variable of air entrained agent mix ratio which are 0%, 0.15%, 0.3%, 0.7% and 1.5% by weight. The reduction range of compressive strength and stress wave velocity has been decreased after reaching the air ratio of 4%. Predicting compressive strength based on stress wave velocity leads to the results of an average error 4.9% in compressive wave velocity and 2.2% in surface wave velocity except for non-AE concrete.