Early strength development of mortar with calcium formate addition curing by electric field in cold climate

Abstract

The rapid development of the early strength of concrete in cold region is the primary measure to ensure its frost damage resistance. In this context, this paper incorporates 2 wt % of calcium formate into a mortar and electrically cures it by passing an AC at a temperature of –10 °C. During testing, a temperature meter monitors the real-time changes in the internal temperature of the mortar under different energization parameters. The strength of the mortar energized for 1 day is analyzed under different energization parameters. Then, the mortar specimens are moved to a standard box to be cured for 3 and 7 days. XRD, TG-DTG, SEM, and MIP characterize the hydration products, microstructure, and pore structure of the electrically cured mortar specimens. The results show that the initial resistance of the mortar specimen with calcium formate is 25% of that of the mortar without calcium formate. The 3- and 7-days strength of the calcium-formate mortar increases by 59% and 29% respectively, compared to the mortar without calcium formate under the same energization parameters. The combined effect of adding calcium formate and applying electric curing densifies the pore structure of the electrically cured mortar.