New recycling technologies of demolished materials for sustainable finishes: the project of concrete reuse on site in Tres Cantos, Madrid

The work presented aims to analyse the feasibility of reusing concrete, once demolished from a building in Tres Cantos in Madrid, to manufacture finishing materials for buildings, as well as to design a procedure. The first phase consists of a bibliographic search on the reuse of materials, analysing the techniques adopted so far and the lines of work. The second phase related to the acquisition of data related to the production and recycling of Construction and Demolition Waste (CDW) at a European level. The third phase consists of the study of recycled aggregates resulting from demolitions or landslides, their treatment process. The fourth and final phase consists of the development of a laboratory test plan to evaluate varied materials for finishing exterior cement pavements with concrete from the demolition of the case study building. There were many conclusions and results of the project. The granulometry of the fine fraction of demolished concrete is suitable to produce non-structural products, such as building finishes and in particular non-driveway outdoor flooring. In terms of flexural and compressive strength, the mechanical behaviour of recycled mixes is lower than that of reference mixes. The recycled mixes show slightly higher capillary absorption capacities than the reference mixes, and the value is higher the greater the percentage of recycled aggregates used (a critical issue which can be resolved by pre-saturating the recycled material).