**5. Conclusions**

The main aim of this chapter is to show how both waste and recycled materials as well as gamma irradiation are adequate tools for improvement of mechanical properties of construction composites. Such materials are reused to replace partially those component concrete materials, such as mineral aggregates. Gamma irradiation is an adequate tool for modification of the physicochemical properties of waste and recycling materials. Moreover, such modified materials act as reinforcements of concrete and as a consequence improve their mechanical properties, through the improvement of interfacial interaction between the matrix and waste or recycled materials. Mechanical properties include compressive and flexural strength, and Young's modulus among others. In general, the results are depending on the particle sizes and concentrations of waste or recycled materials, as well as on irradiation and ratio doses. We believe that this kind of work opens several possibilities in research area of construction with great benefits, in order to ensure economic earnings in the context of sustainable development, by solving environmental pollution problems. Moreover, a simple and inexpensive process based on gamma irradiation is expected.
