Polymer Versus Cementitious Matrix Composites for Retrofitting Reinforced Concrete Columns-A State-of-the-Art Review

Fiber-reinforced polymer (FRP) composites have become a popular solution for upgrading reinforced concrete (RC) structures due to their corrosion resistance, high strength-to-weight ratio, and speed of implementation. However, their organic resin binder has issues, including temperature sensitivity, poor performance in moist conditions, a high cost, and potential health risks. Additionally, reversing FRP repair can be difficult and may damage the original structure, posing a significant reversibility issue. A promising alternative to FRP is the fiber-reinforced cementitious matrix (FRCM), which replaces the organic resin with an inorganic cementitious mortar. This new class of composite uses a breathable textile instead of the tightly packed fibers in FRP. The present article provides a comprehensive assessment of the two composites (FRP and FRCM) used for the retrofitting of RC compression members, with the purpose of identifying existing knowledge gaps and outlining future research objectives. The materials used in different strengthening approaches using both FRP and FRCM have been identified, and their stress-strain characteristics under tensile load have been outlined. The study also explores techniques of implementation using the two materials. This study presents available studies comparing the utilization of FRCM composites with FRP for the axial retrofitting of RC compression members in both ambient and high-temperature conditions.