Experimental study of improved cement silicate grouting material for broken surrounding rock

Abstract

The broken surrounding rock seriously affects the safety production of coal mines. This paper design the orthogonal experiment of fly ash-cement-silicate grouting material and the activation experiment of fly ash to obtain the proportion of the cement silicate grouting material and the activation conditions of fly ash to meet the requirements for supporting the broken surrounding rock. The influence law of water-content ratio, fly ash content, silicate concentration and silicate content on the setting time and strength of cement silicate grouting materials are studied, the influence law of activator content and activation time on the activation performance of fly ash are compared and analyzed. The study of this paper elucidates the hydration reaction mechanism of cement silicate grouting material and the activation mechanism of fly ash. It solves the problems of unreasonable grouting material proportion, unclear activation conditions of fly ash, and difficulty in supporting the broken surrounding rock. The influence law of activator content and activation time on the network structure of grouting materials are obtained. The proportion of grouting materials meeting the requirements is the water-cement ratio of 0.8, fly ash content of 30%, silicate concentration of 40 Be’ and silicate content of 25%, the most optimum activation conditions are that activation time is 2h and activator content is 3%. The influence of cement silicate grouting material on the support effect of broken surrounding rock is obtained, the displacement of the roadway's sides and roadway's roof using grouting materials is 40% and 36% less than that of roadway's sides and roadway's roof without grouting material. The significance of this paper is to deeply analyze the effects of water-cement ratio, fly ash content, silicate concentration and silicate content on the setting time and strength of cement silicate grouting materials and obtain the effects of activator content and activation time on the activation effect of fly ash. Applying the proportion of the cement silicate grouting material and the activation conditions of fly ash in engineering practice has achieved good results, which can increase the stability of broken surrounding rock and effectively control surrounding rock deformation.