摘   要：对不同粉煤灰掺量的钢筋混凝土试件进行弯曲荷载下的盐冻循环试验，利用超声波检测研究了弯曲荷载大小、盐冻循环次数对试件损伤的影响，并分析了超声波波速变化率与弯曲荷载、盐冻循环次数与混凝土损伤度的关系以及200次盐冻循环下混凝土损伤层厚度与弯曲荷载、混凝土损伤度的关系。结果表明：弯曲荷载越大，盐冻循环次数越多，超声波波速变化率和试件的损伤层厚度越大，混凝土受损越严重；试件的超声波波速变化率与盐冻循环次数和弯曲荷载呈线性正相关关系；200次盐冻循环时，试件的损伤层厚度与弯曲荷载呈正相关线性关系，试件的损伤度与超声波波速变化率之间呈非线性正相关关系，与损伤层厚度之间呈对数关系。

Abstract: The salt-freezing cycle tests under the bending load state were carried out on the reinforced concrete specimens with different fly ash content. The influence of bending load and the number of salt-freezing cycles on concrete damage was studied by ultrasonic testing. The relationship between ultrasonic wave velocity change rate and bending load, salt-freezing cycle times and concrete damage degree, the thickness of damaged layer and the magnitude of bending load and concrete damage degree under 200 salt-freezing cycles was analyzed. The results show that the greater the bending load, the more salt-freezing cycles, the greater the ultrasonic wave velocity change rate and the thickness of damage layer of specimens, the more serious the concrete damage. The rate of change of ultrasonic wave velocity of specimens has a linear relationship with the number of salt-freezing cycles and the magnitude of the bending load. Under 200 times of salt- freezing cycles, the damage layer thickness of concrete has a positive linear relationship with bending load. There is a positive correlation and nonlinear relationship between the damage degree of the specimen and the rate of change of ultrasonic wave velocity, and the relationship between the damage degree and the thickness of damage layer is logarithmic.