REACTION OF BETA-DICALCIUM SILICATE AND TRICALCIUM SILICATE WITH CARBON-DIOXIDE AND WATER-VAPOR

The carbonation‐reaction kinetics of beta‐dicalcium silicate (2CaO·SiO2 or β‐C2S) and tricalcium silicate (3CaO. SiO2 or C3S) powders were determined as a function of material parameters and reaction conditions and an equation was developed which predicted the degree of reaction. The effect of relative humidity, partial pressure of CO2, surface area, reaction temperature, and reaction time on the degree of reaction was determined. Carbonation followed a decreasing‐volume, diffusion‐controlled kinetic model. The activation energies for carbonation of β‐C2S and C3S were 16.9 and 9.8 kcal/mol, respectively. Aragonite was the principal carbonate formed during the reaction and the rate of carbonate formation was coincident with depletion of the calcium silicates; C‐S‐H gel formation was minimal. Copyright © 1979, Wiley Blackwell. All rights reserved