Tensile properties of sulfoaluminate cement-based grouting materials toughened by in-situ polymerization of acrylamide

[Display omitted] •The toughness index of the acrylamide modified SCGM (PAM-SCGM) was 57.55 times higher than that of the plain one.•The three-stage failure model of PAM-SCGM and the dual network structure model of PAM-AFt-CS have been proposed.•A model of PAM inhibition of hydration was proposed.•An empirical formulation of a three-stage mechanical model was proposed using Matlab. Its regression was validated. Polymer-modified cementitious materials with high compression and tensile resistance are considered the most promising materials for fracture grouting in underground projects. In this paper, polyacrylamide was prepared by in-situ polymerization of acrylamide, and its toughening effect on sulfoaluminate cement-based grouting material (SCGM) was investigated. The results show that the toughness index of the acrylamide modified SCGM (PAM-SCGM) was 57.55 times higher than that of the plain one. The PAM-SCGM three-stage failure model and the PAM-AFt-CS dual network structure model were proposed and validated by SEM. A model of PAM inhibition of hydration was proposed and validated using heat of hydration, FT-IR and XRD. BET was used to reveal the evolution of the pore structure and validated the tensile model. An empirical formulation of a three-stage mechanical model was proposed and regressed to validate it. The four models and an empirical formulation showed the great potential for engineering applications.