Mechanical Behavior and Freeze-Thaw Damage Modeling of Hydraulic Rubberized Concrete

Abstract

Research Motivation: This study targets two intertwined issues: waste tire recycling and freeze-thaw durability degradation of cold-region hydraulic concrete. Waste tires cause environmental burdens, while cold-region hydraulic concrete suffers service life reduction from freeze-thaw damage. It explores waste tire crumb rubber (WTR) incorporation in concrete for waste valorization and freeze-thaw resistance enhancement, and clarifies ambiguous freeze-thaw/post-freeze-thaw compressive damage mechanisms of crumb rubber concrete (CRC) to support engineering application. Methodology: Material Prep: WTR (5%-15% by cementitious mass, varied particle sizes) was added to concrete; plain concrete (PC) served as control. - Testing: Accelerated freeze-thaw (mass loss, relative dynamic elastic modulus); compressive strength (pre/post freeze-thaw); X-CT (crack propagation); SEM (rubber-cement interface transition zone, ITZ). Key Findings: Freeze-Thaw Resistance: 5%-15% WTR improved freeze-thaw cycles by 30%-50% via rubber’s energy dissipation mitigating cryogenic expansive stress. Strength Trade-Off: CRC showed 10%-25% compressive strength loss vs. PC, due to weak rubber-cement ITZ and increased porosity. Damage Mechanisms: PC follows "pore expansion-crack penetration"; CRC damage involves interface debonding and particle stress concentration, with failure mode shifting from brittle to ductile. Microstructure: SEM revealed loose rubber-cement ITZ; X-CT showed WTR altered pore water distribution and stress transfer paths. Implications: CRC balances cold-region hydraulic engineering freeze-thaw demands and waste disposal. Its performance depends on WTR dosage, particle size, and ITZ bonding. Future research should focus on WTR modification, mineral admixtures, and particle gradation to resolve strength-freeze-thaw trade-off for large-scale application.