Currently, the construction sector is one of the main contributors to significant environmental, social and economic impacts, characterised by high resource and energy consumption, as well as significant waste production. In most cases, this is due to the adoption of a linear model, in which resources have only a single use and their reuse and recycling are not a concern.

In this context, there is a growing need to shift the paradigm in construction and adopt a circular economy model. This model aims to keep resources in circulation for as long as possible, preserving their value and reducing waste production and the extraction of virgin materials. Thus, the circulareconomy has enormous potential to make the construction sector more sustainable.

This work, carried out in collaboration with Saint-Gobain, aims to utilise biomaterials in mortars, by-products from other industries, thereby promoting a circular economy by giving new uses and potential to these biomaterials.

This work proposes the incorporation of rice husks, biochar and wood by-products into new compositions of coating mortars and cementitious adhesives. These biomaterials were selected based on their availability and hygrothermal characteristics, a crucial factor for coating mortars. Regarding the binder used in the coating mortars, a mixture of calcined clay, cement, limestone filler (LC3), and calcium stearate was used. The use of LC3 also enhances the sustainability of the mortars, as it is a compound designed to reduce the amount of clinker used in cement.

In the coating mortars, biomaterials were used as lightweight aggregates, with no other aggregates included in the formulation. In the adhesive cements, an attempt was made to replace the lightweight filler with biomaterials partially.

During this work, an experimental campaign was conducted to characterise the mortars in their fresh and hardened states. It was concluded that the use of biomaterials is viable in coating mortars and adhesive cements.