Influence of the age of epoxy dispersion on the effectiveness of protection of concrete surfaces
The scope of this paper is to test stability and mechanical and chemical properties of a modern freshly mixed epoxy dispersion, and as a variant, of a dispersion which is two years old. During ageing, the dispersion particles probably agglomerate, which is tested by laser diffraction and by sedimentation in a cylinder. Physical-mechanical tests assess the appearance, drying speed and mechanical properties of the film. Chemical tests focus on assessing the resistance of films of dispersions of different ages to common chemicals and to chemical defrosting agents. It is possible to say that two years of dispersion storage lead to a considerable increase in the diameter of a certain number of dispersion particles with the subsequent effect of increasing the sedimentation speed. The hardened film of a two-year old dispersion dries faster, has a rougher surface, is softer, but on the other hand, is less elastic and its adhesive capacity to the substrate is worse. Its chemical resistance is decreased but its defrosting agent resistance remains good. Due to the two-year storage of the epoxy dispersion, most of the monitored parameters decrease, nevertheless, certain protection of concrete structures by a hardened film of such epoxy dispersions is possible.