Bio-based construction composites for improved thermal efficiency: Properties, methods, and performance

This review focuses on construction composites reinforced with bio-based materials and their potential to improve the thermal performance of building envelopes. It analyzes the main experimental techniques used to characterize the thermal, mechanical, and hydric properties of these composites, critically discussing their advantages, limitations, and applicability. Furthermore, the review examines experimental studies within this field. The literature shows that increasing bio-based content generally improves thermal insulation due to induced porosity and microstructural changes, although the optimal amount depends strongly on the matrix type. However, these thermal gains are often accompanied by reduced mechanical strength, mainly caused by increased porosity and weak fiber–matrix adhesion. Moreover, fibrous reinforcements can improve ductility and fracture behavior but tend to weaken the matrix more than particulate additives. Bio-based materials also influence hydric behavior, enhancing moisture buffering or reducing water uptake depending on their type. Finally, fiber surface treatments and gentle coatings are effective strategies to strengthen interfacial bonding and limit mechanical degradation. • Exploration of energy efficiency in the building sector with a focus on maintaining a balance between energy, environmental, and economic factors. • Emphasis on improving the building’s thermal envelope using composites made from construction and bio-based materials as an effective passive solution. • Overview of the key aspects of composites, including their physical properties and their role in enhancing building energy efficiency. • Examination of thermal and mechanical characterization methods used to assess the performance of these composites in building applications.