Force-electric characteristics of cement-based materials with silica fume and fly ash during uniaxial compression

Force-electric of structural materials made early warning viable before structural failure, e.g., by monitoring resistivity of cement-based materials, which could predict main crack about 10 s ahead. Length of this time window might be elongated or shortened by modifying the cement-based materials with different additives. This paper investigated the effect of fly ash and silica fume on force-electric characteristics of cement-based materials. A real-time monitoring system was constructed by digital scatter diffraction (DIC) and multi-functional resistivity measurement instrument to explore and analysis of force-electric response, resistivity development, and surface crack width of cement-based materials under uniaxial compression. Mechanical and electrical response of prisms subjected to uniaxial compression were found highly correlated. We showed that properly defined indicators derived from the high-frequency resistivity measurement were useful for predicting fracture. Addition of silica fume tended to insulate the mortar and delay the electrical response, whereas addition of fly ash was conducive to reduce resistivity and activate the force-electric response of the cement-based materials, the resistivity fluctuation noise was relatively small and the resistivity fluctuation wass the most stable, with the lowest RSDmax and RSDave values of 4502 and 0.086, respectively.