Investigation on basic properties and microscopic mechanisms of polyacrylate latex modified cement grouting material for water blocking and reinforcement

Abstract

Grouting is a highly effective engineering intervention utilized to address water inrush disasters and reinforce weak surrounding rock formations, with the grouting material playing a crucial role in determining the outcomes of grouting operations. To simultaneously meet the requirements of water plugging and reinforcement, a new polyacrylate latex modified cement grout was prepared, consisting of superfine cement, polyacrylate latex, a defoaming agent, and a coagulation accelerator. This study reports on a series of tests conducted to examine the workability, mechanical properties, and microstructures of polyacrylate latex modified cement grout with varying ratios. The experimental results indicate that the addition of polyacrylate latex significantly reduces the bleeding ratio of the grout, as well as improves its groutability and enhances its resistance to dynamic water scouring, particularly under high-flow conditions. The viscosity of the composite grout increases by adding polyacrylate, leading to a decrease in its fluidity. As the proportion of polyacrylate latex increases, the early and final strength of the grout stone body increases while the porosity decreases. The hydration degree of the grout shows a growing trend with the addition of polyacrylate latex based on the observations by low-field nuclear magnetic resonance tests. The modified grout stone body is dense, primarily due to the chemical reaction between calcium ions produced by cement hydration and carboxyl groups produced by the hydrolysis of ester groups on the polyacrylate latex, leading to cross-linking between the inorganic and organic phases and the formation of a complex network structure. Excellent working performance particularly in terms of anti-scour and load-bearing capacity makes polyacrylate modified cement grouting materials highly suitable for use in the simultaneous treatment of water inrush and reinforcement.