Incorporation of hemp fibres in construction products: development and performance testing

Globally, the buildings and construction sector is responsible for a substantial amount of final energy use and CO2 emissions, a significant portion of which result from manufacturing building materials. Therefore, interest has grown in exploring nature-based solutions and materials that incorporate waste and by-products. As the cultivation of industrial hemp in the EUROACE area rapidly increases, construction products incorporating hemp fibres hold great potential to improve sustainability, increase biodiversity and boost local economy. In this context, the present study aims to assess the feasibility of incorporating fibres in several types of solutions.

Looking to develop and validate hemp-based construction solutions, an experimental campaign was conducted to characterize materials and products intended for different applications. First, preliminary physical and chemical characterization tests (e.g. chemical composition, water absorption, specific heat and thermal conductivity) were performed on several types of fibres. Then, we focused on developing mortar formulations, blocks, external thermal insulation composite systems (ETICS) and timber frame solutions. An extensive campaign was performed including hygrothermal, acoustical, mechanical resistance and product specific performance and durability tests. The study included a comparative analysis considering other biomaterials.

The study revealed promising results. Namely, the tested mortars showed good hygrothermal performance and high resistance to mould growth; the hemp blocks showed great thermal performance and adequate reaction to fire; the ETICS solution exhibited resistance to hygrothermal cycles; and the timber frame solution showed great acoustic and thermal performance.

This research was funded by the European Union through the INTERREG VI-A Spain-Portugal Programme (POCTEP) 2021-2027 under the BGREENER project (0066_BGREENER_4_E). The results of the study contribute to validate the incorporation of hemp fibres in construction products, increase the confidence of the farmers and manufacturers, and improve market acceptance of alternative more sustainable products.