9313062 Buyukozturk This project will investigate the role of mortar-aggregate interfaces on the mechanical behavior of high strength concrete composites. the general objective of the project is to establish the fundamental criteria governing the strength, stiffness and ductility of high strength concrete through studies of the material as a composite consisting of a high strength mortar and aggregate system. the emphasis will be on the role of interface toughness on the composite material behavior. Fracture mechanics based laboratory experiments and numerical studies will be performed on concrete models with high strength mortar matrix and aggregate inclusions having different material property combinations with controlled interface fracture characteristics. The required interface fracture toughness data for various mortar/aggregate systems will be assessed based on the approach developed through previous research. The variation of interface strength, achieved using controlled amounts of silica fume, will be implemented in the parametric studies for the properties. The research is expected to provide a fundamental knowledge of the effects of mortar-aggregate interfaces on high strength concrete behavior and to have a direct impact on its production and use in an efficient, economical, and sate manner. ***
