Biocomposite natural fibre pultruded profiles and application possibilities in architecture : case-studies in lightweight structures

Abstract

The selection of materials in the construction industry plays a pivotal role in advancing sustainability goals. Material selection through natural resources is constrained, and therefore, attention has shifted towards the development of novel materials. Fibre-reinforced polymer composites can be reliable substitutes for conventional building materials, particularly because of their high strength-to-weight ratio, which can also reduce material waste. While synthetic fibres, such as glass and carbon, are commonly employed in construction, there is a growing trend toward more sustainable material resources, with increased usage of natural fibres. Natural fibres are derived from various sources, with plant fibres being the most popular due to their high strength, low density, and accessibility as cost-effective agricultural by-products. This study discusses the creation and evaluation of the LeichtPRO-Profiles, pultruded biocomposites intended to be integrated into structural systems as load-bearing elements. Pultrusion, a technology for manufacturing linear fibre-reinforced composites, is a well-established, reliable method. This study explores the optimisation of pultrusion technology through a multidisciplinary co-development approach, examining alternative fibres like flax and hemp and presenting an optimised matrix formulation tailored to specific applications. The study elaborates on the composition and performance of these natural fibre pultruded profiles, showcasing their mechanical capabilities through rigorous experimentation and testing. A primary objective is the application of the profiles in active-bending structures, emphasising the significance of understanding the material's bending behaviour. The most significant case study is a 10-metre-span active-bending structure, the first large-scale structural demonstrator implementing the new material. Nevertheless, additional mechanical and small-scale physical tests confirmed that their structural performance suits a range of other applications. This is demonstrated through several prototypes encompassing applications such as reciprocal, tensegrity, and deployable structures. The extensive case studies presented in this work showcase the applicability of this product to a wide range of applications spanning various scales and thematic contexts. The properties of the developed pultruded profiles demonstrate their suitability for multiple applications, paving the way for their market availability and development of similar biocomposite products.