INNOVATIVE CEMENT BASED THIN SHEET COMPOSITES FOR RETROFIT

2In this paper, a new type of cement-based thin sheet composite will be presented. This innovative technology can be applied to retrofit deficient concrete structures with a superior performance as compared to current Fiber Reinforced Polymer resin (FRP) thin sheets. The greatest potential of FRPs in the near future will be in the areas of repair, strengthening, and rehabilitation of existing structures, such as externally bonded composite fabrics or jackets on beams, columns, and bridge decks. Significant improvements in compressive, shear, and flexural behavior of bonded concrete elements are obtained. In an effective retrofit with external FRP sheets, a layer of dry fiber sheet (usually unidirectional tape) is placed on the top of a coat of polymer resin that will harden to bond the fiber sheet to the concrete structure. The high ratios of strength and stiffness to weight of FRP are primarily responsible for effective retrofit. The strength/stiffness of FRPs is almost entirely attributed to the fibers, since the polymeric matrix has negligible strength/stiffness in comparison to the fibers. Instead of using polymeric resins we develop innovative cement-based matrix materials for making the composites. Cement-based materials have many advantages in comparison to polymeric resins. For instance, much less or no preparation of a concrete surface is required for good bonding. Additional benefits include much higher fire and vandalism resistance, and user friendly to the construction industry