温度和湿度对P-CNT自感知混凝土压敏性的影响

为研究温度与湿度对自感知混凝土(SSC)感知性能的影响,通过低温等离子体改性处理技术对碳纳米管(CNT)进行官能团嫁接,使其在水性体系下获得较好的分散性,并将改性后的CNT(P-CNT)加入混凝土中制备P-CNT/SSC传感器,通过改变含水率与温度条件研究P-CNT/SSC传感器的极化效应与循环加载下的自感知性能。试验结果表明:过高或过低的含水率均不利于SSC的感知性能,其中变化最为明显的是饱水状态下的P-CNT/SSC传感器,其应力敏感系数下降89.8%,并且压敏曲线极不稳定；在变温试验中,P-CNT/SSC传感器的电阻率与温度之间呈现负相关性,高温和低温下的应力敏感系数相较于常温组试件,分别下降了约35.66%和44.53%,并且压敏曲线整体出现了上移或下滑的趋势；P-CNT/SSC传感器在工程应用中的最佳测试环境为常温、自然含水率。

Effect of temperature and humidity on the pressure sensitivity of P-CNT self-sensing concrete

In order to explore the impact of temperature and humidity variations on self-sensing concrete (SSC) efficacy, the functional group of carbon nanotube(CNT) was performed by the low-temperature plasma modification to enhance the dispersion in aqueous systems. The resulting modified carbon nanotubes (P-CNT) were integrated into the concrete to form P-CNT/SSC sensors. Varying water content and temperature conditions were tested to assess the polarization effect of P-CNT/SSC sensor and SSC’s self-sensing capabilities under cyclic loading. Results show that too high or too low water content impaired SSC’s sensing abilities, with the most significant impact observed under full water conditions, leading to an 89.8% decrease in stress sensitivity coefficient and unstable pressure-sensitivity curves. Moreover, during temperature variation tests, P-CNT/SSC resistivity exhibited a negative correlation with temperature. Stress sensitivity coefficients decreased by approximately 35.66% and 44.53% at high and low temperatures, respectively, compared to room temperature specimens, and the pressure-sensitivity curves displayed upward shifts or downward slides. Thus, the study suggests that the optimal testing condition of P-CNT/SSC applications involves room temperature and natural moisture content.