Feasibility of Recycling CDW as Raw Material in Gypsum Composites

On average, Europe generates around 890 million tonnes of Construction and Demolition Waste (CDW) per year and only 50% of this CDW is recycled. This is far from the objectives determined in the European Directive for 2020 and aware of this situation, the European Countries are implementing national policies to prevent the waste that can be avoidable and to promote measures to increase recycling and recovering. In Spain, one of these measures has been the development of a CDW recycling guide for the manufacture of mortar, concrete, brick and lightweight aggregates. However, there is still not enough information on the possibility of incorporating CDW materials in the manufacture of gypsum products. Therefore, the objective of this study is to analyse the feasibility of incorporating some of the most important CDW, which are ceramic waste and expanded polystyrene (EPS) waste, separately in a gypsum matrix. In addition, results are compared, and improvements are proposed in order to optimize the properties of the resulting materials. Results show that it is possible to incorporate up to a 50% of ceramic waste over the weight of gypsum without changing its basic properties. With this addition a 7% increase in surface hardness and a 23% reduction of capillary water absorption can be obtained. On the other hand, with the addition of EPS, a 34% reduction of density and an 8% improvement of thermal behaviour can be obtained. All these results will be incorporated in a waste recycling database, which will be developed by the Universidad Politécnica de Madrid to help promoting the reduction of environmental impact caused by the construction sector.