Enhancing the performance of reinforced concrete structures using engineered cementitious composites: Mechanisms, effectiveness, and design implications

Distinguished by exceptional mechanical and durability properties, engineered cementitious composites (ECC) have emerged as a promising material for structural strengthening applications. Despite extensive research efforts devoted to evaluating the strengthening effectiveness and the ECC-concrete composite action, the underlying strengthening mechanisms remain not fully understood due to wide variety of loading conditions and strengthening strategies. Moreover, inconsistencies and contradictions among experimental observations further complicate the evaluation. In this regard, this study presents a systematic state-of-the-art review on ECC-strengthened RC structural members subjected to compression, flexure, shear, and seismic loading, and the respective strengthening mechanisms are illustrated in term of crack alleviation, interface stress redistribution and structural integrity enhancement. A comprehensive database containing 468 specimens was compiled to evaluate the impact of strengthening schemes, reinforcing materials, interfacial treatments, anchorage measures, and construction techniques on load-carrying capacity enhancement, deformation capacity enhancement, and failure modes. Based on the comparative analyses, the critical factors governing strengthening efficiency are identified, and optimal strengthening strategies are recommended to promote the effective utilization of ECC materials. The findings of this study provide a reliable reference for improving strengthening efficiency, enhancing structural resilience, and extending the service life of reinforced concrete structures.