Carbonation of Reinforced Concrete Structures

This paper presents a general overview of the phenomenon of carbonation of concrete which is inseparable from this building material. Indeed, during the lifetime of the structure, carbon dioxide in the atmosphere enters the concrete from the surface of the material. Carbon dioxide (CO2) can then react with the products resulting from the hydration of the cement. Carbonation gradually changes the chemical composition and internal microstructure of concrete. During the life of the structure, the concrete thus traps carbon dioxide up to 10 to 15% of the CO2 emitted during the decarbonation of the limestone necessary for the manufacture of the cement. Engineers learned during the 20th century to master certain problematic consequences of the phenomenon of carbonation. At the end of the life of the structure, carbonation can, this time, be exploited to fix CO2 in the hardened cement paste of demolition concrete. Recent results show that it is then possible to recapture up to 50 to 60% of additional CO2. Furthermore, this carbonation is particularly favorable for improving the quality of the recycled aggregate from demolition concrete, thereby facilitating its reuse.

Keywords:Carbonation; Concrete; Carbon dioxide; Carbonation depth