基于超声检测的再生混凝土冻融循环损伤机制研究

Study on freeze-thaw cycle damage mechanism of recycled concrete based on ultrasonic testing

基于超声检测方法,研究了不同冻融循环次数(0、15、30次)下不同再生粗骨料掺量(0、25%、50%、75%、100%)试件的声速、声时、波形、频率、振幅和力学性能变化,分析了再生混凝土的冻融循环损伤机理。结果表明:随着冻融循环次数和再生粗骨料掺量的增加,试件的抗压强度降低,声时增大,声速基本呈降低趋势,波形图的振幅衰减且波形趋于平缓,频域图的波峰基本呈降低趋势;超声检测参数有效揭示了再生混凝土在冻融循环下的损伤机制,可为再生混凝土的强度和内部缺陷情况评价提供参考。

Based on ultrasonic testing method,the changes in sound velocity,sound time,waveform,frequency,amplitude,and mechanical properties of specimens with different recycled coarse aggregate contents(0,25%,50%,75%,100%)under different freeze-thaw cycles(0,15,30)were studied,and the freeze-thaw cycle damage mechanism of recycled concrete was analyzed.The results show that as the number of freeze-thaw cycles and the content of recycled coarse aggregate increase,the compressive strength of the specimen decreases,the sound time increases,and the sound velocity basically shows a decreasing trend.The amplitude of the waveform attenuates and the waveform tends to be flat,while the peak of the frequency domain graph basically shows a decreasing trend.The ultrasonic testing parameters effectively reveal the damage mechanism of recycled concrete under freeze-thaw cycles,which can provide references for the evaluation of the strength and internal defects of recycled concrete.