Bernard Barthou1, Lionel Monfront1, and Mounir Bendib1
1)  CERIB (Precast Concrete Industry Research Centre)
CS 10010, 28233 Epernon Cedex, France
e-mail: {b.barthou, l.monfront, m.bendib}

Keywords: Moisture transfer, Simulation, Concrete masonry units, hygrothermal performance.

Abstract. The French Precast Concrete Industry has developed composite concrete masonry units incorporating insulation packers or mineral insulating foam to contribute to the reduction of the energy consumption in buildings. They combine thermal performances and traditional installation method according to the French DTU 20.1 “Building works — Small masonry unit walls”.
To verify that the incorporation of additional material in the formed voids of concrete masonry units does not induce any detrimental consequences due to heat and moisture transfers, a parametric study has been launched taking into account different geometries of concrete masonry units (dimensions, number and shape of the formed voids), different types of concrete (normal weight and lightweight aggregates) and insulating devices in the concrete masonry units (mineral wools, polystyrene, mineral insulated foam…) as well as plastering and rendering mortars considering the French climatic areas.
Calculations has been based on NF EN 15026 to evaluate three acceptance criteria: no condensation, no accumulation of water and limited risk of mold growth.
The results of the simulations show that the incorporation of insulating material in concrete
masonry units does not generate risk of accumulation of water in the wall nor risk of condensation and mold growth.