Protective Performance of Externally-Bonded, Nano-Modified FRP for Concrete
Dr. Xianming Shi
Externally bonded fiber-reinforced polymer (FRP) is a promising tool to use for either preserving the integrity of new concrete infrastructure or mitigating the deteriorations of aged concrete infrastructure. In cold climates, state and local roadway agencies are increasingly relying on the use of chloride salts for snow and ice control, which subject concrete bridge decks, piers, etc. to the combined action of freeze/thaw (F/T) cycling and possible chemical attack. In warm climates near coastal line, the concrete infrastructure is subjected to the ingress of chlorides from the marine environment and the FRP used to protect the concrete is subjected to the combined action of W/D cycling, thermal aging and ultraviolet (UV) aging. Due to its outstanding adhesive characteristics, epoxy resin is the most commonly used polymer for the externally bonded FRP, but without modification the hardened epoxy is generally vulnerable to the attack by moisture and UV.
In this context, the overarching goal of this project is to investigate the protective performance of externally-bonded, nano-modified FRP for concrete in chloride environments, with the focus on resistance to F/T cycles and chloride-based deicers, W/D cycles and UV exposure, respectively. To achieve this goal, this study aims to: 1) investigate the influences of modifying an epoxy resin with nanomaterials (montmorillonite nanoclay, graphene oxide, or nanosilica) and UV-resistant polymer (polyester, aliphatic polyurethane, or polymethyl-methacrylate), individually or in combination, on the mechanical properties and durability performance of FRP/concrete composites under simulated cold or warm climates; 2) both before and after exposure tests, characterize the physical microstructure and chemical composition of the resin and the FRP/concrete interface, as well as their transport properties; and 3) elucidate the role of nano-materials and polyester on the improved resistance against various deterioration distresses, at the micron and nanometer scales.