碳纤维水泥基复合材料导电机理的探讨

通过研究水泥基体的导电性能和不同纤维掺量、外力作用下及掺入骨料后的碳纤维水泥基复合材料的导电性能,探讨碳纤维水泥基复合材料的导电机理.研究表明,水泥基体的电阻随水化时间显著增加,其导电机理是强电解质溶液的离子导电;碳纤维水泥基复合材料的电阻率随纤维掺量增加而显著降低,其电导由接触导电、隧道导电和离子导电3种机制共同决定;碳纤维水泥基复合材料在压力作用下,电阻率因界面接触的改善和纤维搭接概率的增加而降低,在拉力作用下,电阻率因纤维的拔出、折断而提高;骨料的引入增加了复合材料的电阻,这是由于骨料增加了纤维分散的难度和折断的概率,同时阻碍了纤维的搭接并提高了隧道势垒.

Study of conductive mechanism of carbon fiber filled cement-based composites

In order to investigate the conductive mechanism of carbon fiber filled cement-based composites,the conductive property of cement paste and that of carbon fiber filled cement-based composites with different content or carbon fiber,different force action,and addition of skeletonizing materials were studied.The study result indicated that the electrical resistance of the cement paste was obviously increased with hydration time,resulting in ionic conduction in strong electrolyte solution.The electrical resistivity of carbon fiber filled cement-based composites would decrease with fiber content.The contact conduction,tunnel conduction and ionic conduction formed together the electrical conduction in composites.The electrical resistivity of carbon fiber filled cement-based composites would decrease under compression,which was due to the improvement of interface contact between matrix and fibers and the increase in fiber bridge probability.The fiber pull-out and breaking under tension would lead to the increase in electrical resistivity of these composites.The skeletonizing materials could block fiber dispersion and contact,damage fiber and increase tunnel barrier,causing the increase in electrical resistivity of composites.