基于非线性超声的混凝土高温损伤测量研究

Study on High Temperature Damage Measurement of Concrete Based on Nonlinear Ultrasonic

高温作用下混凝土内部会发生物理和化学反应,引起材料的力学性能改变,影响混凝土结构安全。对混凝土在不同高温受热温度和受热时间阶段下的力学性能进行测量试验,研究了混凝土高温损伤下超声波波速和非线性超声系数的演化规律,并讨论了非线性超声方法的适用范围。试验结果表明,当混凝土的高温损伤较小时,非线性超声检测对混凝土材料的高温损伤更加敏感,可以用来更为准确地评估混凝土结构在高温下较低损伤情况。

Under high temperature, physical and chemical reactions will occur inside the concrete, which will cause the change of mechanical properties of materials and affect the safety performance of concrete structures. Hence, the mechanical properties of concrete under different temperature and time of high temperature were measured and the evolution law of ultrasonic wave velocity and nonlinear coefficient under high temperature damage were studied. The limitation of nonlinear ultrasonic method in damage evaluation was also discussed. The experimental results show that when the damage of concrete at high temperature is relatively small, nonlinear ultrasonic detection is more sensitive to the damage of concrete materials at high temperature, which can be used to evaluate the damage of concrete structures at low temperature more accurately.