The current paper aims to promote the application of demolition waste on civil constructions. To achieve this assaignement, two main physcical properties, i.e. dry density and water absoption of the recycled aggregates have been chosen and studied at the first stage. The materail moduli of the recycled materials, i.e. the Lamé's coefficients, and strongly depend on the porosity. Moreover, the recycling materials should be considered as random materials. As a result, the statistical approach would be the most suitable way to handle and assess the level of certitude of the materials behavior as well as structures response.