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Abstract :
[en] Cement will remain the key material to satisfy global housing and modern infrastructure needs. Cement production has undergone a tremendous development from its beginnings some 2000 years ago. Today's annual global cement production has reached 3.6 billion tones, and is expected to increase to some 4 billion tones per year. Major growth is foreseen in countries such as China and India as well as in regions like the Middle East and Northern Africa. Cementitious materials, such as cement pastes and mortars, are the object of a massive use in the buildings, in engineering works or in public roads. their good mechanical resistance properties, justifies having a resort. Another aspect is also taken into account, their durability. From macroscopic aspects transfer coefficients have a direct influence on the mechanical behavior and the durability of the structure, bound to the drying of cementitious materials. In the process of drying many problems are encountered such high energy consumption, kinetic of drying and the final shape of the product. In fact, the improvement of drying system is becoming a necessity. This paper considers the convective drying of an unsaturated wet mortar slab. A calculation model is given, which use the equations of the drying air and those describing the transfer of heat and mass in the porous media. The diffusion model is used to simulate the internal heat and mass transfers. Equations of the drying air (continuity, momentum, energy and mass equations) are written, using the classical assumptions in the boundary layer. The results allow analyzing the drying process, by deducing the space and temporal evolution of the heat and moisture distribution in the porous slab and in the drying air. The evolutions of local heat and mass transfer coefficients on the slab surface are also deduced and analyzed
