A contribution to the characteristic drying curve concept: Application to the drying of plaster

Implicit equations relating the dimensionless drying rate to the reduced mo isture content for porous non-hygroscopic slabs have been determined. This study is based on the receding evaporative front model and on the assumptio n of a parabolic moisture content profile in the diffusional zone of the we t region. The characteristic functions derived depend on the relative posit ion of the receding evaporative front. Two cases were considered : the dryi ng of thick products and the drying of thin products. It has been observed that the relationships corresponding to the C.D.C obtained for thick produc ts depend on the initial. On the other hand, it was observed that experimen tal C.D.C. of plaster slabs determined for many thicknesses and various pla ster textures depend strongly on these two parameters. Furthermore, the mod el presented gives good results only for thin products.