Evaluation of the Properties of High Strength Lightweight Concrete with High Temperature History

Abstract

In this study, we evaluated the compressive strength and ultrasonic velocity based on the temperature and age of ordinary aggregate and lightweight aggregate concrete (30 and 60 MPa) and examined their correlation. The unit weight and compressive strength of ordinary aggregate and lightweight aggregate concrete were measured to evaluate the mechanical properties and examine the correlation between ultrasonic velocity and compressive strength. The W/B ratio was set at 0.41 and 0.28, and measurements were made at 1, 3, 7, 28, 56, and 91 days. The physical properties were evaluated at 23, 100, 200, 300, 500, and 700 ℃. In all test specimens, compressive strength and ultrasonic speed increased with age; and the higher the temperature, the lower the compressive strength and ultrasonic speed. By analyzing the correlation between ultrasonic velocity and compressive strength, a strength prediction equation in the form of an exponential function was found. Moreover, from the error rate test, we confirmed that the strength prediction equation generally had an error rate of 15% or less.