In North West Europe, about 65 Mt of Recycled Fine Aggregates (RFA) are generated yearly from the crushing of Concrete Construction and Demolition Wastes and are disposed in landfills or in banks. In the meantime, 54 Mt of marine sands are extracted in zones where natural aggregate resources are missing, threatening fragile marine spaces. Reusing RFA in concrete would save natural resources.
However, no market exists for RFA owing to rigorous construction standards. RFA is a local resource, with large variability, which is not suited to mass production needing regular materials. But it could be used at a smaller scale, for the manufacture of products needing neither to comply with rigorous construction standards nor to possess high performances. About 5 Mt of RFA could be recycled into concrete for the manufacture of Urban, Memorial or Garden (UMG) furniture, being the starting point of a circular economy loop.
Traditional precast concrete cannot be used for small scale production because of the high share of moulds in the global cost (50 to 80%). However, concrete 3D Printing (3DP) allows manufacturing customized pieces that could be shown by customers as a banner of their identity. UMG furniture are always located in difficult to access zones, reducing their weight by shape optimization and printing them onsite would be easier. Moreover, online control of 3D Printing could be used to compensate materials variability, providing an efficient tool for the valorisation of these resources.
Cirmap will provide a new Mixture Proportioning Method (MPM) for the design of 3DP mortars with RFA and a new Design Methodology for Customized Shapes (DMCS). A new Master Control Command (MCC) for concrete 3DP will be implemented for the equipment of 3DP machines, and an integrated mobile 3D printing unit will be developed for onsite 3D printing of UMG furniture. A Cirmap-network will also be created for lobby and dissemination, leading to a new market for the reuse of RFA. 5 Local Public Authorities in North West Europe will provide public places that will be equipped with 3DP customized furniture.