Evaluation of the properties of a new circular building composite material to upcycle building wastes

A new circular composite material for building applications is developed, made of two secondary raw materials coming from waste recycling: fibers and sand. Hydraulic lime is added as a binder. This new composite targets a low environmental impact thanks to benefits of upcycling buildings waste, low energy production process, lifetime up to 60 years and of a high potential of reversibility, reuse and upcycling. The research focused on mechanical and physical properties, as well as analysis of the microstructure by X-ray 3D microtomography and in-situ compression testing. The mechanical and physical test results show good and unexpected properties: a density of 390 to 1300 kg/m³; a compressive strength between 0.2 and 2.2 MPa, a bending strength of 0.1 to 1.9 MPa and a thermal conductivity of 0.06 to 0.14 W/mK. Further research will focus on circular construction and environmental aspects. Three applications are envisioned, according the standards of the building sector.