碳纤维增强水泥复合材料的机敏性

SMART PROPERTIES OF CARBON FIBER REINFORCED CEMENT COMPOSITES

采用水热热压技术制备了短切碳纤维增强水泥复合砂浆，讨论了以材料本身作为探头时电阻测量信号的机敏效应，并用ＯＭ，ＳＥＭ观察了材料的显微结构．研究表明：材料结构中存在电导渗流现象，受载后材料电阻率下降并导致电导渗流阈值降低；一次加载和循环加载条件下的电阻变化均能反映材料在弹性、非弹性和断裂区间的应力并具有灵敏的响应；碳纤维掺量与材料断裂时电阻相对变化率呈现正比关系。

The smart properties of carbon fiber reinforced mortar prepared by hydrothermal hot-pressing were investigated and the microstructure was observed by OM and SEM. The results show that strain/stress relationship may be detected by measuring volume electric resistance R of the specimen. Variation of R in both once loading and cyclic loading may reflect the stress in elastic, nonelastic and fracture stage with sensitive response. Electric percolation exists while fiber volume fraction φf is higher than critical volume fraction φfc, which changes in the loading process. Fiber volume fraction has a direct proportion with the variation of R while fiber length has an inverse proportion with sensitivity of measurement.