Study on optimization of mix ratio of modified cement based grouting materials based on response surface method

Abstract

In view of the water inrush disaster in karst area, the slurry has the problems of poor dispersion resistance and low retentionrate in the process of grouting and plugging. In this paper, Portland cement is used as the matrix material, and water glassis added to obtain cement-water glass slurry. Then polyacrylamide, iron powder, xanthan gum and guar gum are used asadmixtures to develop a new type of grouting material suitable for dynamic water plugging of water channels. The responsesurface regression model was constructed by Design-Expert software, and the effects of polyacrylamide, iron powder, xanthangum and guar gum on the setting time, slurry retention rate and compressive strength of the new cement-water glass slurrywere analyzed. Combined with the desirability function, the optimal ratio of the new cement-water glass slurry was obtained. The results show that the interaction of each two admixtures has a significant effect on the setting time of the slurry; thesingle factor of xanthan gum and iron powder had a significant effect on the slurry retention rate. The single factor has asignificant effect on the compressive strength of the slurry, and the amount of polyacrylamide has the greatest influence. The model predicts the optimal ratio: polyacrylamide content is 0.6%, xanthan gum content is 0.7%, guar gum content is0.4%, iron powder content is 29.96%, which can provide a reference for the multi-objective optimization of the mix ratioof the new cement-water glass slurry.