Assessment of the durability of polyurea resin coatings against selected aggressive solutions in the sewage infrastructure environment

This article presents the results of a study on how selected chemical solutions affect the durability of specific properties of polyurea resin coatings used for surface protection of concrete in wastewater treatment plants. The solutions tested included sulphuric acid at 1% and 10%, phenol at concentrations of 0.1% and 1%, and urea at 3%. Three randomly chosen coatings were treated with these solutions for 7 and 28 days. After treatment, changes in appearance, weight, hardness, and tensile strength were assessed. Tests were performed using our proprietary methods and in accordance with the standards EN 868 and EN 527-3. It was observed that phenol solutions had the most pronounced negative impact on all polyurea resin coatings, causing significant soaking (up to 30%) and reductions in hardness (up to 40 Shore units) and tensile strength (up to 80%). The 3% urea solution led to a decrease in hardness (up to 17 Shore units) and resulted in notable reductions in tensile strength (ranging from 10% to 30%). Sulphuric acid solutions within the tested concentration range (1% to 10%) caused minor changes in the coatings’ functional properties, including a 10–30% decrease in tensile strength and up to a 14% reduction in hardness.