Concrete is a construction material composed of cement as well as other cementitious materials such as fly ash and slag cement, aggregate, water, and chemical admixtures. Concrete is used more than any other man-made material in the world. This book presents current research on a wide variety of materials that enhance the properties and performance of concrete as well as new recycling technologies. Research is presented on the potential of using of recycled gypsum in cementitious products. Concrete encasements are also used in the storage of radionuclide waste and research is included on the long-term performance of concrete wasteforms. Problems that occur with the oxidation of steel in reinforced concrete structures, which poses serious durability problems, are addressed and the maintenance of these structures, which requires costly-to-rectify solutions are looked at. This book also presents results of tests using Carbon Fibre Reinforced Polymer bars as a potential alternative material to the traditional steel.