Abstract
A method to evaluate the depth of a surface-opening crack in reinforced concrete (RC) member by ultrasonic testing (UT) is studied. Experimental studies are performed to understand the interaction between the size of crack and arrangement of reinforcement. For this end, specimens with a surface-opening crack are made and tested. The effect of reinforcement on the estimated crack depth is studied by applying a model which takes into account P-waves diffracted at the tip of crack and the reinforcement. Concerning the effect of crack surface, the ratio of crack width to crack depth is found to be available for compensating the roughness of crack face.