Investigation into the characteristics of anti-washout underwater slurry modified by blending polyacrylate and polyacrylamide

Addressing challenges related to the poor constructability and low water-to-land strength ratio of polyacrylamide (PAM) cement in underwater repair of hydraulic structures, this study introduces polyacrylate emulsion (PAE) at concentrations ranging from 5% to 25% of the cement mass. The research aims to evaluate the construction performance of modified cement-based materials using truncated cone circular molds, the penetration resistance method, cement loss measurement by weighing, and suspended matter content testing by turbidimeter. Mechanical properties of PAE-modified PAM cement were assessed at 3, 7, and 28 days under both water and land forming curing conditions. Additionally, the microscopic modification mechanism of PAE on PAM cement was analyzed using a scanning electron microscope (SEM). Results indicate that the incorporation of PAE enhances slurry fluidity and extends setting time, albeit at the expense of underwater anti-washout performance. It significantly improves flexural resistance and bonding strength but results in a decrease in compressive strength. The polymer and cement form an interpenetrating network structure, with the membrane filling the pore area and wrapping around hydration products like ettringite (AFt). These factors contribute to better mechanical properties, and the structure of the curing film formed on land is denser.