导电水泥基材料的制备及其电阻率测试方法研究

通过试验比较研究了短切碳纤维在水泥基材料中的两种不同分散工艺，利用SEM观察证实了碳纤维水泥基材料的电阻率主要取决于碳纤维的分散程度和所形成的导电网络的搭接状况。针对导电水泥基材料的电阻率测试，比较了两极组合法与四极法的差异。研究结果表明，湿拌法有利于碳纤维的分散，并可在相同的纤维掺量下获得较小的电阻率。与两极组合法相比，四极法可以避免测试过程中的极化现象，并可消除测试电极与碳纤维水泥基材料之间的接触电阻，因而可以作为导电水泥基材电阻率测试的理想方法。

Preparation and Resistivity Measurement of Electrical Cement-based Materials

Two different techniques in dispersing short-cut carbon fibers in cementitious materials are compared in this paper. From the results of SEM, it is revealed that the electrical conductivity of cement-based materials is dominated by the dispersion of carbon fibers in cement and meshwork formed by the carbon fibers. The two-probe and four-probe methods of measuring the resistivity of cement-based materials are also compared. Test results indicated that wet-mixing technique is more effective in dispersing carbon fibers,and at the same carbon fibers fraction, the resistivity of samples made by this technique is lower than that made by dry-mixing technique. Compared to the twoprobe methos,the four-probe method can not only eliminate the contact resistivity between probes and cement matrix, but also avoid the polarization during test process. Thus,the four-probe method is a perfect measurement way for the resistivity of electrical cement-based materials.