Análise da interferência de soluções ácidas, básicas e sulfatadas em estruturas de concretos e argamassas

Abstract

In 2016, 4.2 billion tons of cement were produced around the world, with a perspective of growth for the following years. Pathologies in concretes and mortars are generally related to the interaction of external agents in the chemical composition of Portland cement, however the internal components may have the same influence. The mixing water is a component that does not have much researches related to its influence, with just a few parameters of criteria. This paper intend to analyze the influence of mixing water with different pH ranges, presence of sulphates and chlorides, on fresh state and hardened concrete aspects, performing visual analysis to observe qualitative aspects and Slump Test, compression and traction strength, ultrasonic pulse velocity (UPV) and X-ray fluorescence, to determine quantitative variations. The feasibility of use an experimental methodology capable to correlate standardized results of specimens at a reduced non-standard scales was also analyzed. For acid and sulfated solutions, a destructive tendency was observed regarding the internal resistance, with a difference between the behaviors of both. In the first one, was observed a delay in the resistance gain process with modification of the inclination of the 28 to 92 days curve segment, while in the second one was only a staggered reduction in the resistances of the standard medium, without any other observation. Regarding basic or alcaline mixtures, an improvement was observed in all aspects analyzed, with better workability in the fresh state, increases in compressive strength of up to 5.50% and traction in 21.52%, greater uniformity of parts, better quality. in ultrasonic tests and better chemical profile, with greater adhesion of components favorable to electrochemical resistivity.