OVERCOMING TECHNICAL AND REGULATORY BARRIERS FOR A BETTER CIRCULAR ECONOMY IN CONSTRUCTION INDUSTRY

The availability of resources for the construction industry is becoming increasingly uncertain, while at the same time the amount of construction waste, but also of industrial and agricultural by-products, is growing. Reconciling needs and secondary resources as well as contributing to reuse is a useful and motivating scientific challenge. But legal and regulatory barriers have to be overcome in order to allow a real circular economy in the construction industry. Working locally and developing an appropriate treatment of Construction and Demolition Wastes is favouring upcycling and valorization of secondary materials for prefabricated and 3D printed concrete. Technical properties of recycled materials are analysed, and proposals are made for increasing the rate of incorporation into concrete prefabricated products. In the same time, minimum requirements are proposed for using recycled sand in 3D mortars. Final properties are compared with classical materials and durability of end products is analysed. Accelerated carbonation process seems to increase recycled sands and aggregates properties (before and/or after manufacturing concrete). But a large and systematic use of recycled materials needs to adapt regulations and requirements for specific applications: this is essential for lowering environmental impact of the construction industry.