Experimental Study of Hygrothermal Behavior of a Hemp Concrete Wall (without and with coating)
Résumé
This study deals with hygrothermal behavior of a hemp concrete wall made of precast blocks and of a timber frame. In a first time, measurements are held on uncoated wall, and then the wall is coated. The experimental device is made of two climatic chambers which ambient conditions are selected to induce vapor transfer, heat transfer or simultaneous heat and vapor transfers. The monitoring deals with temperature and relative humidity in thickness of the wall. Kinetics of temperature and of vapor pressure are given. Profiles are drawn at several times of the transient phase. It is shown that i) under isothermal conditions, homogeneous vapor diffusion occurs, ii) under temperature gradient (without vapor pressure gradient between ambient conditions), huge vapor pressure variations appear, probably due to evaporation-condensation phenomena, iii) the frame is not a thermal bridge, iv) the coating reduces and delays vapor diffusion.