导电功能集料碳纤维水泥基复合材料及其压敏性能

Conductive functional aggregate carbon fiber cement-based composite material and its pressure sensitivity

利用石墨粉和粘土基质烧制成导电陶粒,与碳纤维共同组成复合导电相,制备得到导电功能集料碳纤维水泥基复合材料。采用Instron5882材料试验机,动态电阻应变仪和直流稳压电源测试系统研究了其压敏性,发现压应力对其电阻值有显著影响;从开始加载至破坏全过程电阻值变化表现出均匀下降、平衡和迅速上升3阶段;在低加载应力循环下材料电阻变化值与应力有良好相关性,高加载应力循环下因损伤裂纹的不可复原性而使电阻出现不可逆增加;加载速率对电阻变化也有影响,低加载应力时加载速率影响较小,高加载应力时影响较大。

Conductive cement-based composite material was prepared by using carbon fiber and conductive functional aggregate calcined by graphite particles and clay matrix as composite conductive components.The pressure sensitivity of the composite material was investigated with Instron 5882 materials testing machine,dynamic resistance strain gauge and DC power supply systems,and the results showed that its resistivity was obviously affected by the pressure stress;during the process of loading beginning to failure,the change of resistivity showed even decrease,balance and rapid increase phases.In low level stress loading cycles,the variation of resistivity change had good correlation with pressure stress,but in high level stress loading cycles,the resistivity showed irreversible increase due to the unrecoverable damage cracks.Loading speed also affected the variation of resistivity change,under low loading stress the loading speed had minor effect on the variation of resistivity change,but under high loading stress the effect was relative obvious.