In this study, for the purpose of improvement of estimation accuracy for compressive strength of concrete by ultrasonic method, a measurement method for ultrasonic velocity and a strength estimation method for concrete are investigated. The precision of the developed method for measuring ultrasonic velocity by inserting two probes into the small holes drilled in concrete in structure was confirmed to be high. Further, a method for estimating compressive strength of concrete from ultrasonic velocity through Young's modulus in consideration of the influence of materials was proposed.

In this study, for the purpose of improvement of estimation accuracy for compressive strength of concrete by ultrasonic method, a measurement method for ultrasonic velocity and a strength estimation method for concrete were investigated. In the experiment with reinforced concrete members of actual size, the precision of proposed method for measuring ultrasonic velocity of inner concrete was confirmed to be high. Further, the estimated value of compressive strength of concrete in structure by proposed strength estimation method was close to the actual measurement value.

In this study, for improving the accuracy of estimating the compressive strength of concrete using the ultrasonic method, a method for measuring the ultrasonic velocity and a method for estimating the strength of concrete were investigated. In an experiment with reinforced concrete members of actual size, the precision of the proposed method for measuring the ultrasonic velocity of inner concrete was confirmed to be high. Furthermore, the estimated value of the compressive strength of concrete in structure using the proposed strength estimation method was close to the actual measurement value.