Full-scale prototype wall systems incorporating agricultural bio-based materials: Design, construction, first results of an in-situ monitoring campaign, and preliminary dynamic thermal and acoustic analysis

The incorporation of agricultural residues into construction materials offers significant potential to reduce embodied carbon while improving building performance. However, most studies on bio-based materials remain limited to laboratory-scale characterisation, with fewer addressing their behaviour at full building scale under real climatic exposure. This work presents the design, construction, and first monitoring results of a full-scale test building located in Sant Cugat (Spain), incorporating four distinct prototype wall systems based on corn and sunflower stalk aggregates. Two systems prioritise thermal inertia through earthen bio-composites, while the other two focus on insulation performance using vegetal pith as loose-fill or bonded panels. A preliminary dynamic thermal analysis was carried out by monitoring the temperature evolution at multiple depths of the north- and south-facing wall systems under real summer climatic conditions, quantifying attenuation and phase shift through the temperature decrement factor and time lag derived from frequency-domain analysis. The results reveal clear differences between high-mass and insulation-dominated assemblies. In addition, the interior acoustic environment was characterised through in-situ measurements of sound absorption and reverberation time. The study provides an initial integrated assessment of the thermal and acoustic performance of bio-based wall systems under real operating conditions, supporting their validation as sustainable building envelope solutions.