BIOTERRA

Nowadays, the impacts of construction on environment and health became major stakes. Problems linked with the indoor air quality are considered to be an important risk factor for human health. The current trend tends to improve environmental quality of buildings, dealing with thermal performances, hygrothermal comfort and the use of materials with low impacts. For various reasons (patrimonial, environmental, economic…), there is a resurgence of interest in materials used by human since centuries, as earth and bio-based materials (wood, plant fibres and aggregates). Earth is said to improve moisture regulation into the buildings and consequently users’ comfort. Earth is commonly reinforced or lightened with plant matters. However, under some conditions, development of moulds was observed on the surface of these materials raising many questions as for their use. The BIOTERRA project aims to identify, characterize and offer one (or more) solution(s), with low environmental impact, to the microbial proliferation on earth bio-based products (bricks and plasters) used for construction and restoration of health and durable buildings. This project also aims to develop and validate innovative methodologies for the identification of the microbial strains and the study of their proliferation on building materials. BIOTERRA project is articulated around 4 technical tasks and 2 additional tasks on project management and valorization of the results. The first task will concern mostly the choice of raw materials (earth and plant aggregates), the fabrication of materials of study (bricks and plasters) and the identification of microbial strains present in earth building heritage and in the raw materials used for the study. The second and third tasks will be carried out in parallel and will be strongly interdependent. Task 2 will concern the functional properties of studied materials; in particular, their hygrothermal properties which impact comfort and microbial proliferation studied in task 3. The use of modeling will allow dealing in depth with the experimental results. The main objective of the third task is the study of microbial proliferation and their influent parameters for identified and isolated strains during task 1. Furthermore some solutions to limit proliferation will be evaluated (various recommendations and biological control in order to limit the impact on health). The identification of microbial strains (task 1) and the study of their proliferation (task 3) will be based on the development of innovative methodologies. Lastly, task 4 will concern the validation of tasks 2 and 3 on a large scale with, in particular, the monitoring of offices in building equipped with removable partition-walls made with materials of the study. This highly multi-disciplinary project brings together 9 partners including 5 laboratories: the “Laboratoire Matériaux et Durabilité des Constructions” (LMDC), the project coordinator, the “Laboratoire Génie Civil et Bâtiment” (LGCB), the “CETE of Lyon”, the “Laboratoire de Génie Chimique” (LGC) and the “Laboratoire de Recherche en Sciences Végétales” (LRSV). The “Centre Technique de Matériaux Naturels de Construction“ (CTMNC) reinforces this consortium. Finally, three other industrial partners will participate in this project: Agencement-structure, Agronutrition et les Carrières du Boulonnais.