Etude du comportement hygrothermique d'éléments de construction

Abstract

The development of porous materials requires a thorough knowledge their physical properties. When they are used as heat insulator, the properties which control their capacity of insulation are conductivity and diffusivity thermics. The presence of moisture, some is its origin (rain, capillary condensation, water leakage, hygroscopicity), in the walls of buildings causes damage which extends from the formation of moulds to the complete impregnation while passing by the degradation of the thermal and mechanical performances. Of porous structure, the concrete is a material ready to fix a certain quantity of water (according to the moisture of the surrounding medium). This moisture can modify its thermophysical properties considerably. Experimental measurement is the most effective means which gives access the value of conductivity and thermal diffusivity. The major objective of this study is the determination of the physical properties of materials used like roof (traditional concrete and betostyrene). An experimental work was set up in order to include/understand and to evaluate the thermophysical characteristics of these materials according to the water content. It is significant to retain that the presence of water decreases the capacity isolated from materials. The experimental results also made it possible to specify the effect of the morphology of the medium (solid matrix and porous network), component (standard of cement, type of aggregates) on the thermophysical properties and to show the insulating properties of the reduced concrete.