New circular waste-based material for construction applications by Mélanie HORVATH

Given the environmental challenges related to the construction sector which is one of the most impacting sectors in terms of energy demand, CO₂ emissions, natural resources consumption and waste production, a new class of circular waste-based materials for construction applications is developed. This new class of materials attempts to respond to the environmental challenges through their compositions, applications and environmental impacts, studied through an interdisciplinary research combining materials science, architecture and environment. 

These new materials are made up of two secondary raw materials, i.e. fibres coming from paper waste and sand from inert construction waste, to which a binder is added. The manufacturing process of these materials is very simple and energy efficient as it involves a simple mixing and moulding of the raw materials followed by a natural drying. The research has focused on the characterisation of these materials, by studying their mechanical properties (i.e. understanding the deformation mechanisms in compression and bending), analysing their microstructure (i.e. fibre distribution, inner structure, pores) and studying their physical properties (i.e. thermal conductivity, fire resistance). Two products (i.e. a slab and a block) for three building applications (i.e. as dry screed, infill and partition), based on a sustainable architecture that complies with European recommendations on the circular economy (i.e. taking into account the concepts of circular and reversible construction, facilitating reuse, repair or recycling), were developed according to the construction market needs and the properties of these new materials. Each stage in the life cycle of this new class of materials was considered with the aim of minimising its impact on the environment. A life cycle assessment was then carried out on the entire life cycle of these materials and confirmed their low environmental impact thanks to their high reversibility potential (i.e. their potential for reuse, repair or recycling). 

This new class of materials is therefore positioned as a competitor to materials currently on the construction market, in terms of the targeted architectural applications.