Enhancing sulfate resistance of sulfate-aluminate cement grouting material through acrylamide in-situ polymerization modification

Abstract

Sulfate attack is a major durability issue for cement-based materials. This study investigates enhancing the sulfate resistance of sulfate-aluminate cement grouting material (SCGM) through in-situ polymerization modification with acrylamide (AM). SCGM samples with 0–40 % mass AM were subjected to water and Na2SO4 solution erosion for 28, 180, and 360 days. Mechanical properties, relative toughness, volume changes, pore structure, hydration products, and microstructure were evaluated. Results show that 10 % AM dosage substantially improved sulfate resistance, with 200 % enhancement after 360 days compared to the control SCGM, and a resistance coefficient exceeding 2.2. The 20 % AM dosage provided optimal toughness, with relative toughness remaining above 45. In-situ polymerized polyacrylamide (PAM) facilitated expansive hydration product formation, filled pores, and inhibited microcracking during sulfate attack. However, higher AM levels (30–40 %) reduced strength and durability due to excess swelling weakening the hardened cement structure. Overall, appropriate AM modification via in-situ polymerization significantly enhances the mechanical performance and sulfate resistance of SCGM, with 10 % AM giving optimal durability. This study provides an effective approach to improving the sulfate resistance of cement-based grouts.