Tests of Selected Properties of Construction Mortars Modified with Waste Gypsum Binder Obtained in the Flue Gas Desulphurization Process

The article presents the results of tests of selected properties of plastering mortars that are based on natural gypsum binder, as well as on synthetic gypsum binder from the flue gas desulphurization process. The mortars were analyzed with regards to their durability. For the purpose of the publication, the recipe (quantitative) compositions of the plastering mortars, which differed in terms of the type of used setting retarder (PlastRetard PE and tartaric acid A200), were designed. The mortar recipes were determined experimentally, assuming that the beginning of the setting time was 120 min (the average beginning of the setting time for currently available building mortars), and that the content of the binder was 70%. The assumed research program included tests of flexural and compressive strength, surface hardness, and the adhesion to the substrate. The results of the research confirmed the possibility of modifying the recipe compositions of gypsum plastering mortars.