Engineered/strain-hardening cementitious composites (ECC/SHCC) for resilient cold-region infrastructure: A critical review of freeze-thaw durability

Engineered/Strain-Hardening Cementitious Composites (ECC/SHCC), characterized by their multiphase compositions of fibers, matrix, and interfacial transition zone (ITZ), exhibit exceptional tensile strain capacity , often exceeding 2 %. The freeze-thaw (FT) durability of ECC is a critical factor in the resilience of infrastructure in cold regions. This review examines the effects of FT cycles on the multiscale behavior of ECC, focusing on the changes in pore structure and ITZ properties and their influences on mechanical performance, specifically tensile and compressive behavior under FT conditions. The study analyzes the pore structure evolution mechanisms of ECC under FT cycles and establishes a relationship between compressive strength and pore structure parameters. The changes in micromechanical parameters are proposed to capture the degradation of fiber-matrix bonding and the ITZ under FT cycles, thereby enabling the prediction of its tensile performance. In summary, this study establishes a microstructural and micromechanical framework for understanding the tensile and compressive performance of ECC after FT exposure, offering new insights into enhancing durability and sustainability.