Determination of Moisture Diffusivity during Drying of Mortar Cement: Experimental and Modeling Study

The aim o f th is study is the experimental characterization of the behaviour o f a mo rtar during convective drying. We focalise on mortar that has a rate water-cement of 0.5. The drying tests are developed in a micro-convective dryer that can use samples weighing fro m 0 to 8g. The advantage of these experiments is to reproduce the natural conditions that can be found during the treatment of the mortar-at mosphere problems. The response of the drying curve or the drying kinetic depends on the applied drying conditions. So, the temperature of the air varies fro m 60℃ to 130℃, the velocity of the air is changed fro m 2 m.s -1 to 5 m. s -1 and the relative hu midity is kept less than 1.7%. The co mparison between the experimental results and the proposed analytical solutions of the equation of diffusion represented by Fick's law, applied for a finite shape, allo ws determination o f the values of the d iffusion coefficient. It has a value of 1.71×10 -10 m 2 .s -1 at 60℃, 13.69×10 -10 m 2 .s -1 at 90℃ and 16.27×10 -10 m 2 .s -1 at 130℃. Calculation of the activation energy and the D0 constant are also possible.