Enhancement of magnesium phosphate cement with sintered sludge ash
Jinrui Zhang, Yingnan Qi, Youzhi Yang, Wu-Jian Long, Biqin Dong
Abstract
Magnesium phosphate cement (MPC) is a promising material known for its rapid hardening and high early-strength properties. However, its potential in engineering applications is hindered by its harden at an uncontrolled rate, considerable volumetric distortion and poor water resistance. To address the limitations, this study investigates the influence of sintered sludge ash (SSA) modification on the setting time, volume deformation, mechanical strength and water resistance of MPC. Experimental reveals that the setting time of MPC increase with higher SSA content, and the inclusion of SSA significantly mitigate volumetric deformation. Moreover, the mechanical strength exhibits improvement at all ages, and combine with water resistance analysis, 15% SSA content is the optimal level. Based on the XRD, TG, MIP, and SEM, the mechanism of SSA modification of MPC by releasing MgO encapsulated by hydration products is revealed, indicating an enhancement in the hydration of modified MPC composites and the pore structure becomes dense.