Avaliação da eficiência de uma câmara de carbonatação acerelada projetada e montada em laboratório

Abstract

The carbon dioxide present in the atmosphere penetrates into the porous matrix of concrete internally and dissolves altering the chemical balance of the means. Due to this CO2 dissociation occurs a gradual lowering of the pH, which likely contributes to corrosion of the reinforcement. This research was based on the design and construction of chamber accelerated carbonation, automatically, in four steps, able to equip a laboratory for studying the durability of buildings, especially as regards research related to analysis of cementitious materials. The first step was the realization of the project itself, which is defined dimensions and materials to be used. The second step is intended construction of the carbonation chamber and submitted to the tightness test in order to ensure its sealing. The research continued in its third stage, with automation and microcontroller carbonation chamber through an algorithm developed and programmed, able to interact with the programming present on the sensors and valves commercially available. This stage also included the sensor calibration using internationally traceable standards and conducting pre-tests in reduced model before final installation in the carbonation chamber. The fourth step was to submit the test of accelerated carbonation, cylindrical samples of concrete with dimensions of 100mm x 200mm, inside the accelerated carbonation chamber, according to the standards of the National Laboratory of Civil Engineering - LNEC E-391 (1993) and specification FINAL DRAFT FprCEN / TS 12390-12, the European Committee of Standardization November 2010. The samples were subjected to accelerated carbonation test at 7, 14, 28, 42 and 56 days of exposure and obtained respectively mean depths carbonation 0,00mm, 1,62mm, 2.65mm, 3,35mm and 3,72mm. Finally, the study met its goals with project execution and construction of accelerated carbonation chamber in the laboratory and had their assessed efficiency through calibration of its evaluators devices CO2 and its tightness, and secured its functionality by test accelerated carbonation in a conventional concrete with 365kg / m³ cement CP V ARI and factor a / c 0.50.