利用预设在砂浆块体中的钢筋作为电极,采用交流阻抗谱法,测试了从低频到高频信号激励下三组不同尺度预设裂缝的钢筋砂浆试块的电压值和相位差,计算得到了每个砂浆试块的阻抗谱。研究结果表明,埋设于试块中的钢筋可以直接作为激励和响应信号的发射或响应电极;低频范围内的阻抗幅模不仅可以作为表征砂浆材料特性的本征参数,还可以表征试块中裂缝的尺度;高频范围内,砂浆体的阻抗幅模和相位差均有多个极值点出现,表明该频率范围内包含了其谐振频率;高频范围内试块的相位差显著增加,表明电容和电感对材料的交流阻抗特性影响非常明显。研究成果为今后进一步确定不同预设裂缝砂浆体的谐振频率,以及建立其电容和电感连接组合模型提供了理论依据。
Three groups of cement mortar specimens with various crack were designed to be tested for the peak-to-peak values of volt-age signal,as well as phase difference,based on the ac impedance spectroscopy testing technology.Sine wave pulses with various frequen-cies were used as excitation signal during testing.The reinforcing bars embedded in the mortar specimens were used as the electrodes.The impedance amplitude for each specimen was figured out and the impedance spectroscopy for each specimen was obtained.The results showed that the reinforcing bar embedded in the mortar specimen was reliable for electrode either for stimulus signal or response signal;the impedance spectrums of specimens with the same crack configuration were similar to each other at the range of low frequency,so impedance spectrum was the intrinsic property of cement mortar.However,the impedance spectrums of specimens were changeful and there were a series of peak points in one impedance spectrum curve or in one phase
