Study on synthetic properties of fly ash shotcrete material in underground coal mines

Abstract

A new shotcrete material with high compressive strength, low water absorption rate and controlled coagulation time was developed. The changes of coagulation time, compressive strength and water absorption rate of shotcrete material with different additions of fly ash were studied according to the traditional proportion of shotcrete materials. The improving effects of the synthetic properties of fly ash shotcrete materials with different maintenance periods were studied by normal temperature activation of the new shotcrete materials through the compounding of alkali activator Na2SO4 and polycarboxylic acid water reducing agent. The results show that it is feasible to use the activated fly ash to make shotcrete material for roadway. The combination of AA-Na2SO4 and PAWRa can improve the comprehensive properties of fly ash shotcrete. When 1.5% and 0.5% of AA-Na2SO4 and PAWRa were added respectively, the comprehensive properties of the shotcrete material were the best.