A new enhanced carbonation curing method using monoethanolamine (MEA) solution: Their effects on hydration and microstructure of cement-based materials

Abstract

CO2 curing can improve the properties of cement-based materials and absorb the CO2, which is an effective method for pre-cast concrete. However, the application of CO2 curing is limited for the on-site concrete because the CO2 is hard to diffuse into inner fresh concrete. A new enhanced carbonation curing method has been proposed by using monoethanolamine (MEA) solution in this study. In addition, the effect of new carbonation curing on the compressive strength, hydration and microstructure has been studied. The results showed that the MEA solution can delay the hydration of cement which affects the pore structure and reduce the compressive strength. The effect of CO2-rich MEA solution on the compressive strength of cement paste is quite different from that of MEA solution. The inhibition effect of CO2-rich MEA solution that absorbs carbon dioxide on the early hydration of cement is weak, and the promotion effect on the later hydration is more obvious. The CO2-rich MEA solution can chemically react with the calcium ions in the cement slurry pore solution to generate calcium carbonate, and the small amount of calcium carbonate generated can promote the later hydration of cement.