1990 Volume 110 Issue 2 Pages 121-128
Present paper deals with the basic electrical properties of carbon fiber reinforced cement (CFRC) in order to estimate the electrical applications of CFRC. The distribution of carbon fiber (CF) in the cement composite has been estimated from the electrical properties of CFRC. The EMI shielding effect and the ground resistance decrement effect of CFRC electrode are also studied from the stand point of applications.
CFRCs used are the three dimentional randam type, which are prepared by mixing the portland cement and milled PAN-based carbon fibers with about 30μm in length and 7μm in diameter.
It is possible to estimate the distribution of CF in the CFRC from the electrical resistivity or the relative dielectric constant. Their electrical properties give an average length of the electrical current path and the orientation of Us in CFRC from Sillars' model by inhomogeneous dielectric constant based on dispersed spheroidal particles.
CFRCs have an electrical shielding effect up to frequency of around 400 MHz. And also CFRC with a fiber volume content of 30 vol% decreases ground resistance to about 50% against the direct ground of electrodes.