Towards Industrial Implementation: Experimental Campaign Based on Variations in Temperature, Humidity, and CO<sub>2</sub> Concentration in Forced Carbonation Reactions of Recycled Aggregates

This research presents a sensitivity analysis of various parameters that affect the carbonation of recycled aggregates (RAs), namely CO<sub>2</sub> concentration, temperature, and relative humidity. The range of parameter values is close to that found in cement plant chimneys with regard...

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Bibliographic Details
Main Authors: David Bastos, Catarina Brazão Farinha, Cinthia Maia Pederneiras, Rosário Veiga, José Alexandre Bogas, Ricardo Infante Gomes, António Santos Silva
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/9/5005
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Summary:This research presents a sensitivity analysis of various parameters that affect the carbonation of recycled aggregates (RAs), namely CO<sub>2</sub> concentration, temperature, and relative humidity. The range of parameter values is close to that found in cement plant chimneys with regard to the forced carbonation of RAs. With this purpose, the main characteristics of flue gas streams (CO<sub>2</sub> concentration, temperature, and relative humidity) from two Portuguese cement plants were identified and used in this research. The results indicated that temperatures around 60 °C and CO<sub>2</sub> concentrations around 25% accelerate the carbonation reaction and increase CO<sub>2</sub> absorption in mixed recycled aggregates (MRAs). CO<sub>2</sub> absorption consistently decreased as the relative humidity was reduced from 60% to 40%. The highest amount of CO<sub>2</sub> captured was by a recycled concrete aggregate (RCA) in the conditions of 23 °C, 60% RH, and 25% CO<sub>2</sub>. Overall, the RAs were able to capture a significant amount of CO<sub>2</sub>, ranging from 52 to 348 kg of CO<sub>2</sub> per tonne of cement paste, depending on the nature of the RA. These findings drawn from a parametric campaign provide valuable insights into the potential enforcement of carbonation for recycled aggregates under conditions that closely reflect those found in cement plants.
ISSN:2076-3417