Piezoresistive Mechanism Analysis And Experimental Research Of Carbon Fiber Reinforced Cement

Carbon fiber reinforced cement(CFRC)is a kind of multifunctional material, changing of the internal strain could be reflected by the changing of its own electric resistance. As possessing virtue of low cost and excellent compatibility with concrete, the sensors made with CFRC have widely potential application in the fields of health monitoring of road, bridge, large dram, structure of ocean, atomic power station and other large-scale infrastructures. Around the key problem of CFRC, following research was done in this paper.(1)The material property of the CFRC was discussed. And analysis shows that CFRC possessing both properties of dielectric medium and non- polycrystalline semiconductor. Based on above conclusion, the model for explaining electric conductive mechanism of CFRC was presented. And the piezoresistive mechanism of CFRC was also explained by the model;(2)Some special electrical properties of CFRC were studied. The hysteresis loop curves of CFRC were firstly observed. And above results is the further evidence of that CFRC can be regarded as dielectric material. The piezoresistive of CFRC at different voltage was studied. The results show that, piezoresistive of CFRC is influenced by the testing voltage. In addition, the reason of polarization is also analyzed from view of property of dielectric medium;(3)The preparation technology of CFRC was studied. Experimental result shows that, milling process can not only induce carbon fiber disperse in cement uniformly but also reduce water requirement of cement. The influence of length of carbon fiber on piezoresistive of CFRC was studied. And the results show that, milled carbon fiber is apt to improve performance of CFRC. Analysis shows that it is because carbon fibers become shorter, probability of lap joint between short fibers turn to reducer and the formation of special conductive structure between conductive particles and short carbon fiber.