Characterization of thermal damage and compressive strength during drying at elevated temperatures using ultrasonic pulse velocity

Abstract

This study attempts to visualize the thermal damage on a multiscale level and characterize the thermal damage and compressive strength of concrete using ultrasonic pulse velocity (UPV). First, based on the experimental results of mercury intrusion porosimetry (MIP), nitrogen adsorption, and scanning electron microscopy (SEM), the multiscale thermal damage of concrete subjected to elevated temperatures was visualized. Then, the UPV of the concrete during the entire drying process was detected. Consequently, the thermal damage can be characterized by the UPV. Finally, after considering the effect of both capillary pressure and thermal damage, a compressive strength prediction model, which could reflect the strength evolution during drying at elevated temperatures, was proposed. The model fits well with experimental results and provides an important basis for practical engineering.