静电自组装碳纳米管/二氧化钛水泥基复合材料的自感知性能

Self-sensing performance of cementitious composites with electrostatic self-assembly carbon nanotube/titanium dioxide

基于体积排阻效应,采用导电性能优异的碳纳米管(CNT)和微尺度二氧化钛(TiO_(2))通过静电自组装技术制得CNT/TiO_(2)复合填料并将其与水泥基材料复合,有望发展具有优异自感知性能的水泥基复合材料。为此,对静电自组装CNT/TiO_(2)水泥基复合材料的电学性能及加载幅值、加载速率和含水率等不同环境条件下的自感知性能进行了研究,并分析了静电自组装CNT/TiO_(2)复合填料对水泥基复合材料电学性能和自感知性能的改善机制,最后对比了不同环境因素对自感知性能的影响规律。研究结果表明,当CNT的体积掺量为2.40vol%时,静电自组装CNT/TiO_(2)水泥基复合材料的电阻率降低了99.8%。在循环压缩荷载作用下,静电自组装CNT/TiO_(2)水泥基复合材料的最大电阻率变化率达到49.23%,应力灵敏度和应变灵敏度分别达到8.21%/MPa和812。当加载幅值、加载速率及含水率不同时,静电自组装CNT/TiO_(2)水泥基复合材料均表现出优异的感知性能,其中灵敏度随着加载幅值和加载速率的增加分别降低和提高,但最大电阻率变化率、应力灵敏度和应变灵敏度均随着含水率降低而提高。50℃全烘干状态时,静电自组装CNT/TiO_(2)水泥基复合材料的最大电阻率变化率、应力和应变灵敏度分别达到74.36%、12.39%/MPa和1350。不同环境因素对静电自组装CNT/TiO_(2)水泥基复合材料自感知性能的影响大小顺序为:含水率、加载幅值和加载速率。

Carbon nanotube/titanium dioxide(CNT/TiO_(2))composite fillers were obtained using electrostatic selfassembly technology with combining conductive CNT and microscale TiO_(2) based on excluded volume effect.And then,cementitious composites with electrostatic self-assembly CNT/TiO_(2) was used to develop cementitious composites with excellent self-sensing performance.The electrical properties of cementitious composites with electro-static self-assembly CNT/TiO_(2) were investigated.At the same time,the effects of different environmental conditions on self-sensing performance also were studied including loading amplitudes,loading rates and water content.Additionally,modification mechanisms of electrostatic self-assembly CNT/TiO_(2) composite fillers on electrical and self-sensing performance of cementitious composites were also analyzed.Finally,the effect of different environmental factors on self-sensing performance were compared by radar chart.The results show that electrical resistivity of cementitious composites with electrostatic self-assembly CNT/TiO_(2) is decreased by 99.8%when the volume content of CNT is 2.40vol%.Its maximum fractional change in resistivity is up to 49.23%under cyclic compression.Meanwhile,its stress sensitivity and strain sensitivity can reach 8.21%/MPa and 812,respectively.The cementitious composites with electrostatic self-assembly CNT/TiO_(2) present excellent self-sensing performance under different loading amplitudes,loading rates and water content.The sensitivities decrease with increasing of the loading amplitudes but increase with increasing of loading rates.In addition,the maximum fractional change in resistivity,stress and strain sensitivities increase with the decreasing of the water content.The maximum fractional change in resistivity,stress sensitivity and strain sensitivity of cementitious composites with electrostatic self-assembly CNT/TiO_(2) can reach 74.36%,12.39%/MPa and 1350 under full drying at 50℃,respectively.The radar chart demonstrates that the important orders of the different environmental factors effect on self-sensing performance is water content,loading amplitudes and loading rates.