Experimental study on chloride corrosion resistance of sulphoaluminate cement modified by acrylamide in situ polymerization

In order to study the working performance of acrylamide (AM) in-situ polymerization modified sulphoaluminate cement (SCCG) grouting material in high-concentration underground river brine, its resistance to water and chloride ion erosion was studied. Firstly, the cylindrical test blocks with AM content of 0%, 10%, 20%, 30% and 40% were cured indoors for 28 days; then their axial compressive strength was measured after being immersed in 3%, 6% and 12% NaCl solutions for 180 days. The study found that the in-situ polymerization modification of appropriate dosage of AM can improve the strength, relative toughness and Cl-curing ability of sulphoaluminate cement, reduce porosity, and optimize the proportion of pore structure. PAM encapsulating cement hydration products can reduce the erosion and damage of aqueous solution and Cl-to hydration products, improve the water erosion resistance and Cl-erosion resistance of the overall structure. And at the same time, PAM water absorption swelling can drive the overall structure to absorb water, which can enhance its application in underground humid environment. When the content of AM was too high (≥40%), the volume of the overall structure would lose water and shrink severely or absorb water and expand seriously, demonstrating a significantly reduced performance in its own strength, relative toughness, erosion resistance and other properties. •AM improves the resistance of SCGM to solution erosion.•PAM promotes the ability of cement to cure Cl−.•PAM-AFt flexible-rigid dual network structure provides excellent stability.