Biological Colonisation in Bio-Materials and Composites with Different Bio-Binder Combinations

Abstract

The increasing demand for sustainable and biodegradable materials and products in the construction industry has highlighted the need to understand their biological colonisation susceptibility, particularly in humid environments where fungal growth can lead to material degradation. A number of natural organic materials in raw and different binder-treated states are tested in the current study concerning their fungal resistance with respect to service in building. The studied materials are rice husk, rice straw, Posidonia oceanica, and sunflower stalk, alone and in combination with three different binders: arabic gum, xanthan gum, and sodium alginate. Fungal resistance was tested exposing samples for four weeks under controlled temperature and relative humidity conditions, allowing quantification of mould growth. Results indicate that the tested unbound organic materials are highly susceptible to fungal colonisation. However, fungal proliferation could be significantly reduced by the addition of binders. Among the binders tested, sodium alginate showed the highest effectiveness in limiting fungal growth for all the tested materials, especially when combined with Posidonia oceanica, which presented the lowest bio-colonisation susceptibility. On the other hand, rice husk and sunflower stalk showed the highest fungal susceptibility, even with the application of binders. The results of this work contribute to a better selection of bio-materials and binders in order to enhance durability and sustainability for bio-based construction composites.

Keywords: Bio-based construction products, Biological susceptibility, Bio-fibres, Biodegradable-binder, Biological development, Building materials