Effect of temperature on the carbonation behavior of γ-C2S compacts

Abstract

This study presents experimental results on the carbonation behavior of γ-C2S cured under different temperatures ranging from 0 to 80 °C, including the development in compressive strength and carbonation reactivity, characterization of carbonation products and microstructure. Results indicate the dominant polymorphs of calcium carbonate in the carbonated γ-C2S compacts are found to be calcite at lower temperatures and aragonite at higher temperatures, respectively. Higher temperatures increase early carbonation reactivity and compressive strength while a lower temperature leads to a more sustained development in the two metrics which eventually exceeds those at higher temperatures. This can be accounted for by the premature densification of surface region and the depletion of pore moisture associated with the excessively exothermic carbonation reaction at high temperatures. An improved kinetic model is developed for the simultaneous incorporation of temperature effects on the intrinsic reactivity and the moisture retainment. The obtainment of two parameters ks and kp enables an improved understanding the carbonation behavior of γ-C2S under different temperatures, which will benefit its application as a carbon sink for industrial flue gases.