Co-authors​ :

 Maria Helena CARVALHO TEIXEIRA (PORTUGAL), Andreia ARAÚJO (PORTUGAL), Raquel M. SANTOS , Susana P. B. SOUSA  

In the current global context, climate changes, ecological degradation and the consumption of fossil fuels present significant challenges to the world. Moreover, the building industry consumes a large amount of energy and materials to provide thermal comfort. These challenges, combined with the need for lightweight structures in the building sector, have led to a substantial increase in the scientific investigation of composite sandwiches produced using bio-based materials 1. Composite sandwich panels are typically constituted by two stiff laminates bonded to a soft and lighter core. They offer several advantages ranging from the possibility of prefabrication, high stiffness-to-weight ratio, thermal or acoustic insulation and vibration absorption. Synthetic fibres, such as glass and carbon, are commonly used as skin reinforcement, and polyurethane (PU) and extruded polystyrene (XPS) foams, as well as aluminium honeycomb as core. Still, their production from non-renewable resources contributes significantly to global warming 1, 2. The combination of naturally available materials can provide several environmental advantages owing to their thermal and sound absorption properties, biodegradable nature, cost-effectiveness, and ease of accessibility 2, 3. Flax, hemp, jute, sisal or basalt fibres, and natural cores like cork, bamboo, coir, stone wool and recycled foams are promising examples of natural materials that can offer several economic and ecological benefits 3. In the present work, different materials have been studied for the design and production of composite sandwich panels, including basalt and cork, aiming to analyse and compare their mechanical and thermal properties, and select the most suitable solution for the construction sector. These panels were produced in two different steps: the vacuum infusion of the laminates and the bonding to both sides of the core materials by vacuum-assisted hand lay-up. Initially, the physical properties of the laminates were studied to determine their density and fibre volume fraction. Afterwards, flexural and edgewise compression tests were carried out as they provide important information on the core strength as well as the core/laminate interface. Finally, the thermal conductivity of the solutions produced was also investigated to determine the thermal insulation capacity of the samples. Interesting results have been obtained so far with these new materials for developing sustainable sandwich panels with improved properties.