碳纤维-钢纤维水泥基复合材料电学性能试验研究

为优化水泥基复合材料的电学性能,以碳纤维(CF)和钢纤维(SF)为导电材料,通过抗压强度试验、交流阻抗测试、扫描电镜测试和升温试验,研究了碳纤维和钢纤维的体积掺量对水泥基复合材料抗压强度和电学性能的影响。结果表明,碳纤维-钢纤维水泥基复合材料的抗压强度随碳纤维掺量增大呈先增大后减小的趋势。碳纤维、钢纤维的渗滤阈值分别为0.35%和0.6%(均为体积分数),复掺碳纤维和钢纤维使水泥基复合材料的导电性能大幅增强,产生了明显的正向混杂效应,碳纤维和钢纤维体积掺量达到渗滤阈值后,继续增大纤维掺量对导电性能的提升作用不大。用ZSimp Win软件拟合得到等效电路各电路元件数值,并结合SEM照片分析了导电机制。碳纤维-钢纤维水泥基复合材料具有良好的电热性能,当输入功率为7.9 W,通电30 min、60 min、90 min后,其平均温度可达到33 ℃、43 ℃、50 ℃,通过曲线拟合得到了温度随时间变化的回归方程。

Experimental Study on Electrical Properties of Carbon Fiber-Steel Fiber Cement Matrix Composites

To optimize the electrical properties of cement matrix composites, carbon fiber (CF) and steel fiber (SF) were added into the composites as conductive materials, and the influence of the volume content of carbon fiber and steel fiber on the compressive strength and electrical properties of cement matrix composites were studied through compressive strength test, AC impedance test, scanning electron microscopy test and heating test. The results show that the compressive strength of carbon fiber-steel fiber cement matrix composites increases first and then decreases with the increase of the content of carbon fiber. The percolation threshold of carbon fiber and steel fiber is 0.35% and 0.6% (both are volume fraction). The electrical conductivity of cement matrix composites is greatly enhanced by adding carbon fiber and steel fiber, and an obvious positive hybrid effect is produced. The continuous increase of fiber content has little effect on the improvement of electrical conductivity after the volume content of carbon fiber and steel fiber reaches the percolation threshold. The values of each circuit element of the equivalent circuit are fitted by ZSimp Win software, and the conductive mechanism is analyzed combined with SEM images. Carbon fiber-steel fiber cement matrix composites have good electrothermal performance, when the input power is 7.9 W, the average temperature reaches 33 ℃, 43 ℃ and 50 ℃ after energizing for 30 min, 60 min and 90 min. The regression equation of temperature with time is obtained by curve fitting.