Fly ash-based geopolymer with self-heating capacity for accelerated curing

Abstract

Geopolymers has gained increasing attentions in recent decades because of its potential for CO2 emission reductions. In order to further increase the curing efficiency and save energy, the self-electrical heating fly ash based geopolymer was developed in this paper. In this work, carbon black and steel fibers were added into the fly ash based geopolymer to increase its electrical property. The feasibility of curing fly ash based geopolymer by using self-electrical heating was investigated. Calorimetry measurements were performed to quantify the effect of curing temperature on geopolymerization process of fly ash-base geopolymer. The three-point bending tests were conducted to investigate the influences of electric-heating on the flexural behaviours of geopolymer specimens. The results showed that the maximum surface temperature of geopolymer specimens under electric-heating reached 67 °C, which proved the feasibility of making conductive geopolymer with self-electrical behaviors. The three-point bending test results showed that the flexural strength for specimen significantly increased after self-electrical heating. With the proper addition of carbon black and steel fiber, the fly ash based geopolymer specimen cured after electrical heating possesses a denser micro-structure and therefore exhibits higher strength and better ductility. Besides, self-electrical heating method can significantly increase the eco-efficiency of geopolymer.