Assessment of hygrothermal behavior of newly straw-rape concrete material in various conditions

Abstract

This article focuses on study of hygrothermal behavior of building made of new bio-concrete based on straw-rape. The assessment was conducted using a numerical study, performed using a coupled heat and mass transfer model which takes into account the temperature dependence of the moisture retention curve. The model consists on coupling of envelope model with mono-zone building ambient air model which takes into account ventilation, occupants production and internal inertia in term of thermal and moisture buffering. The model of building envelope was validated by comparison against experimental data carried out on real scale wall. The results reveal that considering moisture retention curve as a temperature-dependent property leads to better prediction of the relative humidity variation in the material, whereas it has weak influence on temperature variations. However, the overall isothermal model may be enough to predict the temperature and relative humidity variations of the indoor ambient air of building. Results have showed good contribution of the internal thermal inertia to reduce temperature variation of the ambient air of building. In addition, simulations highlighted strong capacity, of the straw-rape concrete, to damp the high variations of outdoor relative humidity for all considered climates, especially in desert climate. This effect conduces to avoid accumulation of moisture in the material thus it may rise the life service of the wall.