Isothermal moisture properties of Clayey Cellular Concretes elaborated from clayey waste, cement and aluminium powder

This paper describes a study undertaken to examine the moisture behaviour, in either the vapour or liquid phase of a series of six Clayey Cellular Concrete (CCC) mixes featuring different porosities. These mixes have been obtained by expanding a clay–cement paste through adding a small quantity of aluminium powder during mixing. The material porosity analysis performed using mercury intrusion porosimetry shows that two classes of porosity in the materials derived may be distinguished: microporosity within the clay–cement matrix and macroporosity in the form of gaseous cells dispersed within the matrix, resulting from the chemical reaction between aluminium powder and lime freed at the time of cement hydration. Macroporosity would thus constitute the parameter that differentiates all CCC mixes. Another purpose of the present work is to display how the moisture properties of homogeneous porous materials are expected to change as the macroporosity rate changes. On the basis of experimental results, it will be demonstrated that macroporous cells serve to diminish both the adsorption capacity and sorptivity of CCC; however hydraulic diffusivity in the capillary process increases as a function of macroporosity.