Caractéristiques thermiques des parois des bâtiments et amélioration de l'isolation

Abstract

Optimizing energy consumption is one of the building designers concerns. This explains the technology assessment and development of new building materials. Among these materials lightweight concrete, which can be play a role as an insulator, while maintaining adequate levels of performance. The knowledge of the materials thermal properties used for building shielding such as thermal conductivity, thermal resistance and heat mass are the most important features for the choice of a thermal insulation material This work is a contribution to the study of cork lightweight and polystyrene lightweight concretes thermal behaviour. These materials are intended to be used for roof insulation and other building components and there lightness makes them an interesting technical solution for the building tower. Regarding the experimental measurements, in steady regime for the thermal conductivity, we have used the “Boxes method”. Thermal resistance and mass heat are obtained by calculation. The experimental results made it possible to specify the effect of the water content, the materials density and the fibres dosage on the materials thermophysical properties. The mathematical modelling of coupled heat and mass transfer occurring within building walls is obtained with using Luikov's model. The differential equations obtained are discredited by the finite element method. The obtained results illustrate the temporal evolutions of the temperature and the moisture content, and the distributions of the temperature and moisture content inside the wall for several periods of time. They allow us to specify the effect of the nature and fibre dosage on the heat and mass transfer.