Performance of typical cement suspension-sodium silicate double slurry grout

Abstract

To plug dynamic water effectively during underground constructions, it is important and urgent to determine the performance of quick-setting cementitious grouts. In this study, the Ordinary Portland cement (OPC) and sulphate aluminium cement (SAC) were selected as two typical cements, and the double slurry were prepared with cement suspension and sodium silicate slurry. The fresh-state properties of cement single slurry i.e., mini-slump, flowability and bleeding; basic work performance of double slurry i.e., flowability losing time, anti-washout and initial or final setting time; flexural and compressive strengths; failure mode; brittleness evaluation and microstructure of the double slurry grout were studied. The water/cement (W/C) ratio was selected as 0.6:1–1.2:1. The volume ratios of cement slurry and sodium silicate were 1:1, 2:1, 3:1 and 5:1. The results show that the sodium silicate slurry disturbed and accelerated the normal hydration process of cementitious minerals, and the SAC was not suitable for preparing double slurry compared with OPC. The flowability losing times of SAC double slurry were higher than those of OPC double slurry. The anti-washout, failure modes of OPC double slurry have more advantages. Considering the flowability losing time, controllability, pumpability, diffusibility, mechanical strength, failure mode and microstructure, the volume ratios should not be over 5:1 and not be less than 2:1.