Influence Of Accelerated Carbonation Of Recycled Fine Aggregate On The Properties Of Concrete.

Abstract

In recent decades, the use of recycled materials has been on the rise, primarily for the purpose of sustainable development and environmental protection. The carbonation process is capable of permanently mineralizing carbon in the form of aggregates to meet the growing market for eco-friendly products as a carbon-free material. The reduction of CO2 emissions in the industry can be integrated with waste treatment, which can be used in the construction industry in the formulation of green cement and as aggregate in new concretes. This article evaluates the impact of using a carbonated recycled fine aggregate on the properties of concretes that replace 100% of natural aggregates with recycled aggregates. An accelerated carbonation treatment is applied to the fine fraction of recycled aggregate (0-4 mm) in a controlled environment of: (i) Relative Humidity = 75%, (ii) CO2 concentration = 20%, and (iii) residence time of 24 hours. This results in an 8.42% increase in the formation of CaCO3 compared to the uncarbonated fine fraction and a 40% decrease in water absorption compared to the uncarbonated fine aggregate. The produced concretes exceed 35 MPa of compressive strength at 28 days of curing, and the effective porosity does not exceed 5%, indicating a concrete of good quality and durability.