Electrothermal effect of alternating current on hardening process of metakaolin-based geopolymer

This work investigates the effect of alternating current (AC) curing and ambient temperature curing on the hardening process of metakaolin-based geopolymer (MKG). Two processes were related to the conductive behavior in the hardening process: the slow process (the linear tail near the low frequency end) and the fast process (the typical hemi-circle near the high frequency). A thermo-electric model based on Arrhenius equation was presented and the experimental results were in good agreement with the calculated values. In addition, this article presented a new explanation of the coagulation mechanisms underlying the hardening behavior of electro-curing geopolymers: fast-coagulation under high voltages and slow-coagulation under low voltages exhibit significantly different effects on pore structure.