Study on time-varying viscosity of cement and sodium silicate grout under seawater condition

Abstract

For practical purposes, the grouting technique is an effective method to strengthen weak rock masses around subsea tunnels, while clarifying the effect of seawater condition on grout properties is the basis for engineering applications. This study mainly focuses on the time-varying viscosity of grout under seawater condition. The cement and sodium silicate (C-S) grout with different ratios that commonly used in engineering cases was selected in this study. Through the digital display rotating viscometer (NDJ-8S), the time-varying viscosity of C-S grout was obtained. Moreover, the comparative analysis of grout viscosity under seawater and freshwater conditions was made. The test results show that the time-varying viscosity of C-S grout was obviously influenced by seawater condition and volume ratio (C-S ratio). The variation process of C-S grout viscosity with time under seawater condition can be divided into three stages: (a) initial stage, (b) stable stage and (c) rising stage, while there are only two stages under freshwater condition. Furthermore, the viscosity of grout in seawater is much greater than that in freshwater at the initial stage. After that, the time-varying viscosity models of C-S grout with different ratios were obtained on basis of experimental data. It is hoped that the obtained data will provide aids to the design of grouting with C-S grout in the future.