碳纤维石墨导电沥青砂浆压敏性能研究

以碳纤维与石墨作为导电相材料,通过室内制备导电沥青砂浆试验,分析了不同碳纤维掺量、石墨掺量、石墨碳纤维两相复合对沥青砂浆电阻率的影响;通过循环加载试验分析了材料的压敏性及可逆性;引入电阻率变化率Fn、单位应力下电阻率变化值Kn两个参数,通过数理统计,探讨了不同循环加载次数下Fn、Kn变化的规律与趋势。试验结果表明:碳纤维与石墨的掺入可以有效降低沥青砂浆的电阻率;材料电导率随压应力的增加而增加,随压应力的卸载而下降,有较好的压敏性;Fn、Kn随循环加载次数有很好的相关关系;随着循环荷载次数的增加,单位应力下电阻率变化值减小,机敏可逆性趋于稳定;进一步改善材料设计,减少材料的塑性变形,对保证初期检测结果的可靠性十分重要。

Research on pressure sensitivity of the conductive asphalt mortar with carbon fiber and graphite powders

Conductive components were prepared by carbon fiber and graphite powders, and the relationships between different dosage of carbon fiber, graphite powders and asphalt mortar resistivity were investigated by aboratory test. The material pressure sensitivity and pressure-sensitive reversibility were analyzed by cyclic compressive loading test. The change rate of electrical volume resistivity Fn and the fractional change in resistivity per unit stress Kn were analyzed. The regularity and trend of variations of Fn and Kn under different loading circles were discussed by the mathematical statistics method. The results showed that the carbon fiber and graphite powders could reduce the resistivity of the asphalt mortar effectively. The conductivity increased with the compression stress and decreased with the compression stress increasing unloading, which showed good pressure sensitivity. There was a good correlation between Fn, Kn and numbers of cyclic compressive loading. With the loading cycles increasing, the change in resistivity per unit stress decreased, demonstrating that the reversibility of material tend to be stable. Reducing plastic deformation is very important to the reliability of initial detection results.