高延性混凝土冻融损伤的超声波研究

Study on damage of high ductility concrete under freeze-thaw cycle by ultrasonic wave

通过采用快速冻融法对高延性混凝土(HDC)试件进行了不同冻融循环次数下单轴受压试验,研究HDC的抗冻性能,测定不同冻融循环次数作用后HDC的表观特征以及质量变化。同时,采用超声波平测法对不同冻融循环次数HDC损伤层厚度进行测定,研究冻融循环对混凝土损伤层厚度的影响规律。研究结果表明:HDC在冻融循环作用下质量最大损失率仅为0.004%,HDC试件未出现明显剥落,表现出良好的抗冻性能。通过分析HDC损伤层厚度及损伤层平均抗压强度试验数据,对预测模型计算结果与试验结果进行比较,发现模型计算值与试验值基本一致。

The high ductility concrete(HDC) specimens were subjected to uniaxial compression tests under different freeze-thaw cycles by using the rapid freeze-thaw method to study the freezing resistance of HDC, and to determine the apparent characteristics of HDC under different freeze-thaw cycles. In addition, ultrasonic testing method was used to determine the damaged layer thickness of HDC specimens under different freeze-thaw cycles, thereby the influence law of freeze-thaw cycle on the damaged layer thickness of concrete was studied. Research results indicate that the mass maximum loss rate of HDC is only 0.004% under freeze-thaw cycles. The HDC specimen did not peel off significantly and showed good frost resistance. By analyzing the HDC damage layer thickness and the average compressive strength test data of the damage layer, the calculated results of the prediction model are compared with the experimental results, it is found that the calculated values of the model are basically consistent with the experimental values.