Moisture in Self-levelling Flooring Compounds. Part I. Water Vapour Diffusion Coefficients

Abstract in Undetermined Diffusion coefficients of three self-levelling flooring compounds (SLC) and water vapour resistance of a primer have been measured with the cup method. The results show that the diffusion coefficient is dependent not only on the vapour content (relative humidity), but also on the absolute moisture content, i.e., there is a hysteresis effect on moisture transport. At RH lower than approximately 90 %, SLC have higher diffusion coefficients than a standard concrete (w/c 0.7 OPC), but the opposite is true at higher RH. This can be explained by the fact that SLC have different pore structure than concrete. The latter may also be an effect of the high amount of polymer in SLC that form a film throughout the material and thereby limits capillary moisture transport