3D-printed clay components with high surface area for passive indoor moisture buffering

This study focuses on implementing a novel approach in which clay 3D-printed matrices were designed as a passive comfort solution to enhance indoor moisture buffering and air quality. Liquid Deposition Modeling additive manufacturing and parametric design were implemented to develop the components, which were characterized for having an increased specific surface exposed to air and moisture per volume unit, which showed to significantly enhance moisture buffering. This revealed a clear linear relationship between the two parameters. Additionally, the components showed a significant increase in the practical Moisture Buffering Value (MBV) and mass reduction compared to a solid clay reference. Furthermore, this research analyzed the influence of two stabilization techniques on the moisture uptake capacity of the samples, i.e. thermal treatment at different temperatures between 600 and 1000 °C and mixing with calcium hydroxide paste within the 10–40 % range. Finally, the morphological (scanning electron microscopy) and crystallographic (X-ray diffraction) analyses of the samples show a correlation between microstructural modifications and the variations of moisture uptake capacity and MBV. In addition, nitrogen adsorption-desorption measurements revealed that sample porosity decreased as the temperature of the thermal treatment increased, showing a correlation with the decrease of practical MBV. [Display omitted] •3D-printed panels fabricated by LDM increased macroscopic exposed surfaces from 0.27 to 4.06 cm2/g.•Practical MBV of unfired clay panels increased 3 times with 35 % less material usage.•Thermal treatment degrades kaolinite and montmorillonite, reducing water affinity.•Calcium hydroxide preserves unfired clay structures with less impact on moisture affinity.•Thermal treatment decreases porosity and moisture capacity, reducing MBV.