Valorizing waste tire rubber in freeze-thaw durable one-part slag-based alkali-activated materials through plasma-induced interfacial activation.

The accumulation of waste tire rubber poses serious environmental challenges due to its chemical stability, non-biodegradability, and potential release of hazardous substances. Incorporating waste rubber particles (WRPs) into alkali-activated materials (AAMs) provides a promising pathway for waste valorization and enhanced freeze-thaw resistance. However, the hydrophobic and chemically inert nature of untreated WRPs results in weak rubber-matrix bonding and defective interfacial transition zones (ITZs), limiting their practical application. Herein, plasma treatment was employed to improve the compatibility between WRPs and one-part blast furnace slag (BFS)-based AAMs. The effects of plasma-modified WRPs on mechanical properties, freeze-thaw durability, pore structure, interfacial characteristics, and internal deformation behavior were systematically investigated. Plasma treatment increased the surface hydroxyl content and roughness while improving wettability, enabling stronger interfacial interactions between WRPs and the AAM matrix. Compared with untreated WRPs, plasma-treated WRPs effectively mitigated freeze-thaw-induced strength deterioration, pore coarsening, interfacial debonding, and crack propagation. After 100 freeze-thaw cycles, plasma-treated WRP composites exhibited compressive strength loss rates below 20% and significantly reduced residual strain accumulation. This work demonstrates an environmentally benign strategy for high-value waste rubber recycling and provides a pathway toward durable low-carbon AAMs for cold-region applications.