Electrical characteristic and piezoresistivity of carbon fiber graphite cement-based composites containing CCCW
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摘要: 利用四电极法研究了内掺水泥基渗透结晶防水材料(CCCW)的碳纤维石墨水泥基复合材料试样(40 mm×40 mm×40 mm)的导电特性及其在循环荷载作用下的压阻特性，分析讨论了碳纤维石墨水泥砂浆的体积电阻率及压阻特性随石墨掺量的变化规律。碳纤维和CCCW的掺量分别为水泥质量的1%和4%；石墨掺量分别为水泥质量的0%、10%、20%、30%、40%和50%。结果表明，添加CCCW的碳纤维石墨砂浆试样的体积电阻率随石墨掺量的增加迅速下降，并存在渗滤现象，渗滤阈值为20%左右。在循环荷载作用下，不同石墨掺量试样的电阻和应力存在一定的对应关系。石墨掺量为水泥质量的20%～30%时，碳纤维石墨水泥砂浆试样的体积电阻率与压应力呈现良好的可重复性，电阻值在应力加载时几乎呈线性下降，而卸载时增加。Abstract: The electrical conductivity and pressure-sensitivity of carbon fiber (1% mass fraction of cement) graphite (0% 50% mass fraction of cement) cement-based composites samples (40 mm×40 mm×40 mm) containing CCCW (cementitious capillary crystalline waterproofing materials，4% mass fraction of cement) were measured by the four-probe method and Instron 5882 system. The variation trend of volume resistivity with graphite contents and pressure sensitivity at different mixing amounts of the graphite were discussed. The results show that the resistivity of carbon fiber graphite cement-based composites containing CCCW versus the concent ration of graphite curves has typical features of percolation phenomena. The percolation threshold is 20% (mass fraction of cement). The corresponding relationship between stress and resistance exists with different contents of graphite under the action of cyclic loading，and it comes to the conclusion that when the content of graphite is up to 20%～30% mass fraction of cement，the pressure sensitivity is the best.
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Key words:
- arbon fiber /
- graphite /
- CCCW /
- percolation threshold /
- piezoresistivity
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