Study on properties of Portland cement-sulfoaluminate cement-based grouting materials modified by in-situ polymerization of calcium acrylate

To enchance the toughness of ordinary Portland cement-sulfoaluminate cement-based grouting material and minimize the secondary damage of road structure caused by stone body destruction under vehicle load. In this paper, the development laws of setting time, fluidity, and mechanical strength of grouting material, and the characteristics of stone damage under the action of calcium acrylate are systematically analyzed. The mechanism by which in-situ polymerization of improves the toughness improvement of ordinary Portland cement-sulfoaluminate cement-based grouting material is then revealed. In-situ polymerization of calcium acrylate de-lays the setting time, and an appropriate calcium acrylate content improves the flowability. The addition of calcium acrylate largely enhances the mechanical strength of the stone body, improving the 1-day compressive strength and flexural strength by 279.18% and 301.64%, respectively. Calcium acrylate also increases the flexural compression ratio of the stone body. The highest flexural compression ratio at 28d is 0.5592. The microscopic analysis reveals that calcium acrylate promotes hydration, and forms stable calcium polyacrylate in the stone body, which connects the hydration products into a more densely cement-calcium polyacrylate com-posite structure. Consequently, the toughness of the stone body improves. By analyzing the stress-strain curve, the stone body still exhibits a capacity to resist damage after the peak stress under the action of calcium acrylate. Finally, a damage constitutive equation of the stone body with different damage factors is established, which has excellent agreement with the test curve and can predict the mechanical properties of cement-based grouting material modified by in-situ polymerization of calcium acrylate. The findings provide a theoretical framework for designing the strength of grouting materials and evaluating road stability.