CO2 uptake analysis of wastewater-pretreated carbonated recycled concrete aggregates

Abstract

Considering the high rates of pollution associated with concrete fabrication and usage, researchers are studying and proposing alternatives that aim to be less harmful to the environment. For the production of concrete, as stated by the principles of biomimicry, one of the possibilities discovered was inspired by nature's ability to absorb and sequester carbon dioxide (CO2). In concrete, this mechanism is possible due to the presence of calcium hydrates in cement, which reacts with CO2 through the process of carbonation. Since cement is the element related to the possibility of applying CO2 into the material, it is also possible to employ this new technology in recycled concrete aggregates (RCA), in which carbonation process allows the improvement of its characteristics, thus turning feasible its utilization in concrete. Furthermore, thinking of ways to optimize the absorption of CO2 during carbonation reaction, the pretreatment of RCA with concrete wastewater, which contains a high concentration of calcium, is studied. Bearing in mind the benefits linked to this new approach to concrete fabrication, the research proposed in this document aims to investigate the potentiality to absorb CO2 and consequent improvement of wastewater pretreated carbonated RCA. This project also aims to complement the ongoing research "The potential of biological processes at the biomimicry context for the conception of innovative concretes", proposing a practical analysis to integrate an alternative identified with great promising potential for improving sustainability in building industry. (AU)