Foamed gypsum for multipurpose applications in building

Gypsum plasterboards are nowadays very appreciated in buildings, mainly due to their lightness, thermal insulation and suitable sound transmission loss when used in double walls. However thermal and acoustic features of gypsum plasterboard can be enhanced. In the present study an innovative method, consisting in the direct addition of a pre-manufactured foam to gypsum pastes is used to increase the gypsum porosity improving sound absorption, lightness and thermal insulation features. In this aim, the role of both different amounts and dilutions of a vegetal foaming agent on the main physical, mechanical and microstructural characteristics of the gypsum was experimentally investigated. Moreover, also X-ray computed micro tomography technique (Micro-CT) was carried out in order to investigate the 3D internal microstructure of the materials. The results confirmed the effectiveness of the foaming agent in increasing the gypsum porosity, with a linear correlation between densities and mechanical strengths. Moreover, the presence of large bubbles, mainly connected each other, involved in a strong reduction of the thermal coefficient (λ), from 0.57 W/m∙K of REF sample to 0.25 W/m∙K of LG10_5% sample, and in a strong increase of the normal sound absorption coefficient (α0), from 0.06 of REF sample to 0.20 of LG10_5% sample. Finally, in the light of the results obtained by the present research, the use of a pre-whipped vegetal foaming agent represents a suitable way to obtain lightweight gypsum-based materials with enhanced thermal and acoustic properties.