Study on the toughening of calcium aluminate cement-based grouting materials by in-situ polymerization of acrylamide and the mechanism of toughness change

In order to address the high brittleness and cracking risk of calcium aluminate cement-based grouting materials (GM), the study introduced the in-situ polymerization of acrylamide (AM) to toughen GM (P-GM). A comprehensive evaluation was conducted on the mechanical deformation, strength, reaction products, microstructure, and pore structure of samples with AM monomer contents from 0 to 40 wt%. The results indicated that the AM monomer reduced the hydration rate and extent of GM, leading to an increased polymerization degree of AM in the P-GM specimens. Additionally, the bonding between AM and cement particles, coupled with the flocculation and adsorption effects of polyacrylamide (PAM), effectively improved the weak interfacial bonding between different phases. The P-GM specimens exhibited significantly increased deformation capacity, with deflection increasing by 9172.60 % and tensile strain by 1027.69 %. However, the deformation ability of the samples decreased at later stages. Based on these findings, the study proposed a mechanism for the toughening of P-GM and the subsequent reduction in toughness, providing insights into the hydration mechanisms of organic/inorganic composite.