ECC/FRCM-Confinement of Concrete Columns: Understanding the Symbiosis Interaction Between Fabric and Matrix

Engineered Cementitious Composite (ECC) and Fabric Reinforced Cementitious Matrix/Mortar (FRCM) systems have emerged as a promising solution for the structural strengthening and/or seismic retrofitting of Reinforced Concrete (RC) columns offering greater compatibility with concrete and improved fire resistance compared to epoxy-based composites like Fiber Reinforced Polymers (FRPs). The efficacy of these systems is fundamentally linked to the synergistic interaction between the fabric reinforcement and the cementitious matrix, which plays a critical role in ensuring effective confinement and overall mechanical performance. This study delves into the impact of various ECC/FRCM systems on the behavior of confined concrete columns subjected to pure compression, with a particular emphasis into the fabric-to-matrix symbiosis. At this scope, an extensive experimental program was carried out, involving different types of fabric (i.e. Carbon, Glass and PBO) and matrix compositions to evaluate their influence on compressive strength, ductility, and failure mechanisms of RC columns. Furthermore, additional tests were conducted without the fabric component to isolate and quantify the matrix’s standalone contribution to the confinement system’s overall effectiveness. The results highlighted significant performance variations stemming from the compatibility and congruency between the deformability characteristics of the fabric and matrix. These findings underscore the importance of precise material selection and optimization to fully harness the structural benefits of ECC/FRCM systems, paving the way for their advanced application in RC column strengthening.