A new paper has been published from Cement and Concrete Composite:
N. Saeki, L. Cheng, R. Kurihara, T. Ohkubo, A. Teramoto, Y. Suda, R. Kitagaki, I. Maruyama, Natural carbonation process in cement paste particles in different relative humidities, Cement and Concrete Composites. 146 (2024) 105400. https://doi.org/10.1016/j.cemconcomp.2023.105400.

In this paper, cement paste particles, simulating concrete waste, were carbonated under natural CO2 concentrations at different relative humidity levels to see how the rate of carbonation changed. The particles were ideally small enough to allow water migration to occur more rapidly than the carbonation reaction, and it became clear how the hydrates reacted with CO2 to produce carbonation in a humidity-dependent manner. These results will be useful as a basis for the re-fixation of CO2 in concrete waste in the future.