Carbon fiber reinforced concrete as an electrical contact material for smart structures

Concrete containing 0.2-0.4 vol.% short carbon fibers was found to exhibit volume electrical resistivity of 10³-10⁵ Ω.cm and contact resistivity (between the cured concrete and stainless steel) of 10³-10⁶ Ω.cm at zero contact pressure. Increasing the contact pressure from 0 up to 0.05 MPa was sufficient to lower the contact resistivity to a minimum value. Increasing the fiber content to >0.4 vol.% did not decrease the contact resistivity, but decreased the volume resistivity. The values of the volume and contact resistivities depended on the non-fiber additives (i.e., latex, methylcellulose and silica fume) needed for fiber dispersion. The use of latex gave a high volume resistivity (1×10⁵ Ω.cm) and a low contact resistivity (5×10³ Ω.cm²) compared to the use of methylcellulose and silica fume; the high volume resistivity was due to the large proportion of latex used; the low contact resistivity was due to the lack of adherent on the surface of fibers protruding from the concrete containing latex.