Correlation between the Ultrasonic Pulse Velocity and Elastic Modulus for Concrete Considering the Influence of Coarse Aggregates at High Temperatures

Abstract

This study analyzed the effect of the hardness of coarse aggregates mixed in concrete on the ultrasonic pulse velocity (UPV) and elastic modulus after high temperature exposure. Specimens were classified into normal concrete (NC) mixed with normal aggregates and lightweight aggregate concrete (LC) mixed with lightweight aggregates, and the water-to-binder ratios (W/B) were set to 0.41, 0.33, and 0.28 to determine the characteristics at various strengths. The mass loss, UPV, and elastic modulus were investigated, and the target temperatures were set to 23, 100, 200, 300, 500, and 700 °C. In addition, the correlation between the UPV and elastic modulus was analyzed according to the W/B. After high temperature exposure, the residual mechanical properties for LC improved compared to those for NC, and the LC graph exceeded the NC graph owing to the correlation analysis between the UPV and elastic modulus. Finally, an equation for predicting the elastic modulus based on the UPV after high temperature exposure was proposed.