Conductive behavior of engineered geopolymer composite with addition of carbon fiber and nano-carbon black

Abstract

Geopolymer has potential advantage in electrical conductivity. The conductive and mechanical properties of engineered geopolymer composite (EGC) with carbon fiber (CF) and nano-carbon black (NCB) were studied respectively in this paper. Firstly, the percolation thresholds of CF and NCB were determined, and then the effect of curing age, moisture content and temperature on the conductivity were analyzed. The fluidity, compressive and flexural strengths and tensile ductility were also analyzed. Finally, the conductive behaviors were studied by combing electrochemical impedance spectroscopy (EIS) and equivalent circuit model. The results indicate that the higher the dosage, the better the conductivity, the percolation thresholds of CF and NCB are 0.05 vol% and 15 vol%. Curing age, moisture content and temperature have important effects on the conductivity, but the effects are restricted by the dosage of conductive fillers. The more the dosage of the CF, the smaller the effect, while the NCB has little limited effect. CF and NCB also have important effects on the mechanical properties and the CF-EGC and NCB-EGC still have high ductility. Finally, an equivalent circuit model is proposed which can well characterize the conductive behaviors under different conditions.