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International audience; Bio-based materials such as straw are becoming a promising alternative to improve the building energy performance and to reduce its carbon footprint. When compared to common building construction materials, bio-based materials control the temperature and the relative humidity variation to ameliorate the indoor comfort with a low embodied energy and CO2 emission. This paper presents a comprehensive review of the thermal and mechanical properties of straw-based materials and buildings. The objective is to synthesis the work that has been carried out by the research community and to compare the results. The paper first introduces straw bale as a construction material from a historical viewpoint and in the context of the current building sector. The second part focuses on the available chemical and microstructural data of the straw fiber. The third part refers to the thermophysical and mechanical properties of the bales. The fourth part reviews the numerical and experimental studies done at the wall scale. The fifth part describes straw bale construction methods considering the regulation, structure requirements, and life cycle assessment data. Last, a critical analysis of the currently available data on straw as a building material is carried out and pending research issues are discussed. It was found that, despite abundant literature on structural and thermal properties of straw bale constructions, there is still a lack of some information. At a fiber scale, more research should be done to compare straw fibers to other natural and synthetic fibers. At a bale scale, further pH-related research is needed because it affects the material's interior conditions and durability. In addition, a thermal conductivity model for straw should be developed. On a bigger scale, the hygrothermal characteristics of various types of walls must be measured and computed experimentally and theoretically under various exterior and internal situations. More research is needed to improve the sound resistance of the straw wall by adding new layers capable of absorbing acoustic waves. Studies on the energy behavior, cost analysis, and how interior air moisture is self-regulated in straw buildings are needed at the building size. Therefore, a lack of consistent data among the different studies was noted depending on the straw characteristics.

L’utilisation du béton végétal comme le béton de chanvre est devenue de plus en plus répandue dans les constructions en remplacement des matériaux classiques traités sous des procédés industriels dans un contexte environnemental critique. Le béton de chanvre est un matériau de remplissage connu pour ses propriétés hygrothermiques et environnementales ainsi que pour le confort induit par ces performances multiphysiques. L’objectif de cette étude est de quantifier l’impact de ce matériau sur les performances énergétiques du bâtiment selon une approche pluridisciplinaire. La première partie est consacrée à l’état de l’art lié aux usages du béton de chanvre et à ses performances en comparaison aux matériaux classiques du génie civil. Un travail préliminaire qui consiste en une étude bibliographique approfondie portant sur les modèles proposés dans la littérature a été également entrepris. La seconde partie est consacrée à un travail de caractérisation expérimentale sur béton de chanvre permettant d’identifier les paramètres nécessaires au modèle numérique. La troisième partie est dédiée à l’étude du comportement hygrothermique d’une paroi et d’un local en béton de chanvre soumis à des conditions climatiques statiques et dynamiques dans le but d’évaluer l’impact du matériau sur la demande énergétique ainsi que le confort des usagers., Academic Journal of Civil Engineering, Vol 36 No 1 (2018): Special Issue - RUGC 2018 St Etienne