Effects of moisture on thermal conductivity of the lightened construction material

• The influence of moisture content on the thermal conductivity of lightened concrete is studied.
• Lightening the concrete by olive pomace increases its thermal insulation capacity.
• Thermal conductivity increases rapidly with water content.
• The water absorption capacity of the lightened concrete is very sensitive to the addition of olive pomace.
• Compressive strength decreases with the increase in the proportion of olive pomace.

The major objective of this study is the determination of the physical and mechanical properties of building materials lightened by vegetable fibers, used as heat insulator. An experimental work was set up in order to include/understand and to evaluate the thermo-physical and mechanical characteristics of these materials according to the water content. The experimental results show a significant decrease in the material density and in the thermal parameters with the increase in the percentage of vegetable fibers in the concrete. The results also show the effect of humidity on the thermal conductivity. The composite material studied offers interesting thermal insulation, and consequently an optimal gain of energy in comparison to common construction materials.