As it had been demonstrated for more than a half of a century, construction and demolition waste, steel slag, other industrial and domestic wastes or by-products, have a potential for being transformed in construction materials. Not only concrete, bituminous mixtures or granular materials for roads have been considered, but new products have been developed to extend his field of application. Researchers have very often concentrate his efforts in recycling this transformed waste materials, but they subsiste several questions about the durability under different environments and in particular about his real sustainability. The consideration of the high contents in cement used in some recycled concretes, can be a good example to discuss about his sustainability. Durability problems have to be considered in the specific environment, as leaching have to be. We have to adress the obtention of recycled materials from environmental perspective, and durability is an environmental concept, some times more complex that we can deduce considering only the general specifications.