Roughness and Surface Free Energy of Silicate Brick Hydrophobised with Emulsions of Low VOC Content

The aim of the research presented in the paper was to evaluate the feasibility of using hydrophobising agents based on organosilicon compounds for impregnation of silicate bricks. The process of surface hydrophobisation both using solvents and water substances was analyzed. The effectiveness of four preparations which differed in terms of hydrolytic polycondensation degree, viscosity and concentration, as these are the factors that are decisive as far as the end result of hydrophobisation is concerned. The following laboratory tests were performed: the analysis of physical properties of the tested materials, water absorption coefficient of the hydrophobised samples, water vapour diffusion, frost resistance, contact angle, surface free energy, roughness and the analysis of silica gel properties in electron microscopy. Based on the results of the above mentioned, the analysis of effectiveness and desirability of hydrophobisation using emulsion with a low VOC content was carried out. (paper)