High Dosages of Set Accelerator in Fibre Reinforced Shotcrete

Aluminium sulphate-based shotcrete set accelerators (also called activators) are known to influence the rate of early-age hydration in shotcrete. This is the primary motivation for their widespread use throughout the mining and tunnelling industries. However, these admixtures are also known to change the degree of compaction that can be achieved with a given shotcrete mix and they can alter the age-dependent post-crack performance of Fibre Reinforced Shotcrete (FRS). The present investigation was undertaken to assess the magnitude and character of these changes in performance as the dosage rate of set accelerator is raised to higher than normal rates.