Research on the preparation and properties of a novel grouting material based on magnesium phosphate cement

Abstract

Abstract A novel grouting material based on magnesium phosphate cement (MPC) was prepared by two-component grouting method with additions of fly ash (FA) and ground granulated blast furnace slag (GGBS). The main concern of this research is to study the influences of the addition of GGBS on the properties of MPC-grouting material, which were determined in terms of the properties of the fresh slurry, mechanical properties, water resistance, hydration products and microstructures. The results showed that GGBS reduce the setting time obviously and increase the fluidity in a certain amount, reaching to a maximum of 302 mm at a level of 20% content of GGBS. The addition of GGBS can improve the mechanical properties and water resistance of the samples. Moreover, the hydration products analyzed by X-ray diffraction (XRD) and the microstructures observed by Scanning Electronic Microscopic (SEM) illustrated that GGBS promote the hydration to produce more struvite during the late stage, and the new hydration products were formed surrounded by the residual reactants, making the structure denser. The pH value of the resulting grouting slurry was around 7.0 and the stone ratio was high, which indicated that the novel MPC-grouting material blended with GGBS and FA could meet the requirements well and was friendly to the environment.