Cox The U.S. civil infrastructure is in a desperate state, and there is an increased interest in applying composite materials to solve infrastructure problems. One application of composites is to reinforce concrete with their fiber reinforced plastic (FRP) bars and grids. This application is particularly well suited to concrete structures subjected to a corrosive environment and to special structural systems that must be insensitive to electromagnetic fields. In civil engineering design, a precursor to structural failure is often provided by the ductility of the system's components. While steel reinforcing bars can provide this precursor, FRP reinforcements generally do not. Approaches to this problem include developing hybrid reinforcing elements that exhibit higher strain at failure, embedding sensors in the reinforcement, and tailoring the surface structure of the FRP elements to provide a precursor to failure through interface slip. All of these approaches benefit from a better understanding of the mechanical interaction between the concrete and FRP reinforcing elements - the primary topic of this study. Understanding this mechanical interaction is also important toward understanding the durability of the FRP reinforcing elements. ***
