Avaliação da influência de sistemas de proteção na permeabilidade de água em placas cimentícias com incorporação de perolas de poliestireno expandido

Abstract

Water is one of the main elements responsible for the emergence and propagation of pathological events in coatings. Its permeated presence compromises the protective capacity, as well as directly influences durability, and can accelerate the deterioration of mortars, impairing their useful life. It is known that the use of surface protection instruments (painting system) and the use of waterproofing additives in the production of mortar coatings directly influence the protection against water permeability. Within this aspect, this study aimed to evaluate the degree of influence of protection systems for cement boards with the incorporation of Expanded Polystyrene (EPS). EPS was used in the cement board as a partial replacement for sand, in a volume of 20%. Two types of painting systems were evaluated, one for indoor environments and the other for outdoor environments, in addition to a type of waterproofing water-repellent additive, which was applied to the mortar mixture. This evaluation was carried out using two methods that analyze the permeability of mortar coatings: the Karsten tube test (pipe method) and the permeability test of ABNT NBR 15498/2021, which deals with the requirements for using cement boards. The mechanical properties of the mortars and boards were also characterized. The results of this work demonstrated that the protection systems evaluated caused different effects on the permeability of the boards. The waterproofing additive did not significantly influence the permeability of the panels, only the physical characteristics, with greater emphasis on the mass density and water absorption properties. The painting systems positively influenced the waterproofing capacity of the panels, with the external painting system being more efficient. Regarding the permeability assessment techniques, the Karsten tube showed great variability in the results, demonstrating that this technique is more sensitive to the conditioning variables. And, in the permeability test of NBR 15498, all panels passed the use requirement.