Tensile Performance and Aging Increase Factor Constitutive Model of High-Strength Engineered Cementitious Composites under Sulfate Salt Attack

This study investigates the uniaxial tensile behavior of high-strength engineered cementitious composites (HS-ECCs) in sulfate erosion environments. Five different sulfate erosion ages were established (0 days, 30 days, 60 days, 90 days, and 120 days), and the development of the macro-mechanical properties of HS-ECCs was revealed from a microscopic perspective using scanning electron microscopy (SEM). The results indicate that, under the influence of sulfate erosion, the strength of HS-ECCs exhibits a trend of initial increase followed by a decrease, while ductility shows a continuous decline. This phenomenon is primarily attributed to changes in the microstructure and reaction products. Based on the test results, an aging growth factor was introduced to fit the stress–strain curve, demonstrating that the model can effectively predict the tensile performance of HS-ECCs with greater accuracy compared to traditional models. This study not only provides data references for the engineering application of HS-ECCs in sulfate environments but also offers a novel approach for constructing predictive models in other environmental contexts.