Pseudo-dynamic carbonation for concrete curing and carbon storage

Abstract

Concrete demonstrates the capacity to absorb carbon dioxide. The reaction between concrete and carbon dioxide accelerates concrete curing at early age and converts CO2 into calcium carbonate for carbon storage. As-captured flue gas without recovery can be directly used in this application. Because of low CO2 concentration in flue gas, a pseudo-dynamic carbonation process was developed with multiple injection and releasing cycles. The effect of process parameters on carbon uptake and strength gain was examined. It was found that, with a flue gas of 25% CO2 concentration and 2-hour carbonation, cement paste could uptake CO2 of 8-11% based on cement content in immediate carbonation and concrete could absorb CO2 at 7-9% after 18-hour initial curing. The maximum possible carbon uptake from flue gas carbonation was also determined. It was about 15-17% based on cement mass. While immediate carbonation could significantly enhance the early strength, carbonation after initial curing did not improve significantly the late strength.