Strength and microstructural evolution of alkali-activated slag-based cemented paste backfill: Coupled effects of activator composition and temperature

The activator concentration/silica modulus and curing temperature play critical roles in the engineering performance of alkali-activated slag-based cemented paste backfill (AAS-CPB). Different types of AAS-CPB samples, as well as CPBs made of OPC, were tested at different curing times and temperatures (10 degrees C. 20 degrees C, 30 degrees C, and 40 degrees C). The results show that the strength of AAS-CPB is more sensitive to changes in curing temperature, and the strength of AAS-CPB is consistently higher than that of CPB made of OPC. Moreover, the strength evolution of AAS-CPB is strongly affected by the coupled effect of curing temperature and activator concentration/silica modulus. An increased activator concentration and a reduced silica modulus can improve the early strength of AAS-CPB under a low curing temperature, but it can also weaken the improvement in the late strength of AAS-CPB under warmer curing temperatures. These findings could contribute to successful application of MS binder to the mine backfill operation. (C) 2022 Published by Elsevier B.V.

Automated summary

The concentration of activator/silica modulus and curing temperature are important factors affecting the engineering performance of alkali-activated slag-based cemented paste backfill (AAS-CPB). The strength of AAS-CPB is more sensitive to changes in curing temperature and consistently higher than that of CPB made of OPC. The strength evolution of AAS-CPB is strongly influenced by the combined effect of curing temperature and activator concentration/silica modulus.