Carbonatación acelerada en agregados reciclados de concreto y evaluación de su desempeño en mezclas de concreto para vías

Abstract

This degree work aimed to optimize some operating conditions of the accelerated carbonation process used in the treatment of recycled coarse aggregates concrete, evaluating some physical, chemical, hardness and durability properties as well as their performance in concrete mixes for vehicular roads. The project was developed in three stages. In the first stage, some parameters of the accelerated carbonation process were evaluated and the influence of the humidity content of the ARC in the carbonation process to determine the optimal parameters of CO2 fixation to the ARC in the carbonation chamber. In the second stage the optimum carbonate ARCs were characterized comparing their properties in relation to natural aggregates and non-carbonated ARCs, verifying compliance or not with the requirements established in the INVIAS 2013 standard section 200 " stone aggregates", finally, as a third step, 7 concrete mixtures were developed for tests of resistance to compression, and calculation of modulus of elasticity and rupture, verifying compliance with the INVIAS 2013 standard "General Road Construction Specifications" Chapter 5 - Concrete Pavement. The results of the first stage indicate that the parameters to obtain the optimal CO2 fixation to the aggregate correspond to temperature 23°, humidity of the ARC dry in oven, exposure time of two weeks For maximum size of ¾ ", 10% of CO2 concentration (maximum of the camera) and relative humidity of 65%. When the experimental program was executed in the second stage, physical properties, particle size, hardness, durability, cleaning, particle geometry, chemical and others (PH measurement) were measured, the results for the optimum carbonate ARCs indicate that it comply the requirements of the general road construction specifications INVIAS 2013, with the exception of the elongation index. The accelerated carbonation process in recycled concrete aggregates with maximum size of ¾ ", improves some characteristics with respect to non-carbonated, such as, increased density, decrease in absorption percentage, and improves performance in the presence of sulfates. The third stage demonstrated that concrete mixtures with 100% optimal carbonated ARC comply the requirements stipulated in the general road construction specifications INVIAS 2013, in reference to slump, compressive strength measured at 7 and 28 days, density, modulus of elasticity measured at 7 and 28 days, as well as flexural strength at 28 days. A similar behavior was observed between the 100% ARC and carbonated ARC mixtures in relation to the resistance to compression at 7 and 28 days, respect to the modulus of elasticity an increase in considerable magnitude occurred from 7 to 28 days.