Preparation and performance study of a novel conductive geopolymer

A novel conductive geopolymer (GP) based on fly ash (FA) and modified by carbon fiber (CF) was successfully developed in this study. Detailed investigations were conducted on various factors influencing resistivity, such as the type and content of CF, liquid-solid ratio, modulus of alkali activator, and the material's sensitivity to temperature, pressure, moisture. The research findings highlight that short-cut CF enhances both the electrical conductivity and mechanical properties of GP, along with its sensitivity. Specifically, at an FA and short-cut CF mass fraction of 80% and 1.0% respectively, the resistivity and compressive strength of GP reached 5.58 Ω·m and 51.20 MPa, representing a 99.95% reduction in resistivity and a 40.66% increase in strength compared to pure GP. Additionally, the introduction of CF1 into the modified GP exhibited significant negative temperature coefficient and piezoresistive effects. Furthermore, FA not only enhanced the conductivity but also improved its water resistance of GP. This study provides a creative opportunity for design and fabrication of novel conductive intelligent GP materials.