Análise da durabilidade de concreto leve de argila expandida com camada protetora submetido a meio agressivo ácido

Abstract

The lightweight concrete has reduced specific mass, providing the use of smaller sections and thereby reducing the design of foundations. Now a day the problems concerning durability has occasioned by deterioration of the structure, indicating the need to develop new materials and methods to increase the quality of concrete. The concrete when exposed to adverse conditions must be protected to maintain the absorption and surface corrosion at acceptable levels. This paper presents the assessment of a reference concrete and a lightweight expanded clay concrete protected by an acrylic layer and also protected by an epoxy layer, exposed to an aggressive environment (H2SO4 2, 5%) immersion. From de dosages studies, was selected a concrete prepared with 370kg/m3 of cement and the water-binder ratio of 0.50 corresponds to the value established in NBR 6118 (2014) types for concrete subjected to highly aggressive environments. The lightweight concrete produced presented specific mass of 1,740kg/m3, dry consistency and compressive strength of 30 MPa. Visual inspection shows that the protected bodies of proof of lightweight concrete presented a clear reduction of the loss of cohesion of the paste caused by the attack as well as lower water absorption and mass loss. In water absorption and mass loss tests, was observed a good performance of acrylic protection and, also of epoxy protection, preventing the penetration of aggressive agents in concretes with surface protections. This research allows proving that the layers assessed as surface protectors presented a good adherence level to the substrate and efficiency, reducing the penetration of the aggressive agent, thus minimizing degradation and increasing durability of the lightweight expanded clay concrete.