Development of a method for assessing resistance to mold growth: application to bio-based composites

Abstract

The production of insulating materials for buildings obtained from the valorization of agro-resources is a promising way both in terms of ecology and hygrothermal performances of these composites. However, the lack of information on their resistance to mold development limits their use. The mold development is indeed likely to cause health problems and to induce damage. There is therefore a need to classify the materials according to their resistance to mold growth and disintegration in order to use them appropriately. The purpose of this paper is to propose a test method that qualifies bio-based composites with respect to their performance. An accelerated aging test was carried out on 5 composites made with two different agro-resources (hemp and rape) with different binders. It consists in exposing the specimens to a temperature of 30°C and a relative humidity of 90 %RH for three months. During the test, the specimens are regularly photographed and weighed. The evolution of two indicators is thus measured over time: the sample mass and the percentage of its external surface contaminated by fungi. At the end of the test, a microscopic view makes it possible to identify the species of the molds which have contaminated the composite.