Abstract:

In order to study the correlation between rebound value and axial compression performance of high- strength concrete after being exposed to high temperatures and water cooling,a total of 117 concrete prismatic blocks were designed for rebound detection and axial compression test with the highest temperature, constant temperature time, and concrete strength grade as parameters. The influence of various change parameters on the rebound value and the axial compressive strength were analyzed. The relationship of concrete strength and rebound value after exposure to high temperature and water cooling was fitted by formula based on the relevant specification and measured data. The results showed that: before 400 ℃ ,some rebound values and compressive strength increase, and after 600 ℃ , both of them drop sharply. When the temperature is constant for 1.0 h and the temperature exceeds 600 ℃ , the rebound value and compressive strength decay the most. At 200 ℃ and 800 ℃, the concrete strength grade has the most significant impact on the rebound value and compressive strength.In general, changes in various parameters have a greater impact on compressive strength. The calculated value of the formula obtained by the quadratic polynomial fitting meets the requirements of the specification, and can reflect the relationship between the rebound value and compressive strength after exposure to high temperatures and water cooling.

Key words: high temperature, water cooling, high-strength concrete;rebound method, axial compressive strength