Review of Ultrasonic Pulse Methods for Evaluation of Mechanical Properties of Concrete with Different Percentages of Non-sintered Hwangto at High Temperature

Abstract

In this study, the effect of non-sintered hwangto on the high-temperature residual mechanical properties of concrete is analyzed. The specimens are classified as NC and HT, which are mixed with 15% and 30% non-sintered hwangto, respectively, and the W/B is set 0.33. The unit weight, compressive strength, and ultrasonic pulse velocity of the specimens heated at room temperature and at 100 °C, 200 °C, 300 °C, 500 °C, and 700 °C are analyzed, and the correlation between ultrasonic pulse velocity and residual compressive strength is analyzed. The analysis result shows that the higher the mixing ratio of non-sintered hwangto, the lower is the mass loss rate at high temperature and the higher is the residual compressive strength of HT compared with those of NC. Meanwhile, the ultrasonic pulse velocity of HT is similar to or slightly higher than those of NC in areas with high temperatures of 300 °C or beyond. Results of correlation analysis shows a difference of approximately 10.0% between the NC and the HT specimens.