Innovative Sustained High Strength Silicate Based Shotcretes
Due to early strength requirements, shotcrete mix must incorporate rapid set accelerating agents to speed up mix set time and accelerate hardening. Silicate-based shotcrete accelerators have demonstrated good early compressive strength, short set time and good stiffening properties at relatively low cost. The silicate-based shotcrete mix also has minimal impacts on health, environment and improved safety. However, it can exhibit relatively significant loss of compressive strength over 28 days, which presents a critical challenge. The aim of this project is to develop low-cost and environmentally-friendly silicate-based accelerators that exhibit rapid setting, strength gain and minimal 28-day loss of strength. This will rely on understanding the interactions between silicate accelerators and cement, and compatibility issues. The research will focus on enhancing mechanical, hydraulic and microstructure properties of shotcrete mixtures at different curing temperatures and ages, as well as evaluating durability privilege of silicate-based shotcrete mixtures over alkali-free shotcrete mixture accelerators.