Hi, a new paper on accelerated_carbonation of hardened cement paste has been published in Cement and Concrete Research. In this study, we conducted accelerated carbonation experiments on cement pastes incorporating supplementary cementitious materials (SCMs) with varying Ca/Si ratios. The results revealed that a lower Ca/Si ratio does not necessarily lead to inferior carbonation resistance. Rather, it was found that at certain Ca/Si ratios, the development of sheet-like C–(A)–S–H structures improves durability to an extent that outweighs the potential decline in resistance due to reduced calcium content.

Furthermore, the study demonstrated that accurate prediction of carbonation front development under accelerated conditions can be achieved by considering both the moisture transport coefficient in the carbonated zone and that in the uncarbonated zone. Even with a simplified model in which the carbonation front is assumed to form at a specific moisture content, and where the moisture transport coefficient shifts accordingly, the progression of the carbonation front could be reliably predicted across all sample types.

In summary, this study provides new evidence that under accelerated carbonation conditions, moisture transport governs the overall rate of carbonation, reinforcing its role as the rate-limiting factor in the process.

The paper is open access, please check it:

L. Cheng, R. Kurihara, Z. Yang, T. Ohkubo, R. Kitagaki, A. Teramoto, Y. Suda, I. Maruyama, Accelerated carbonation fronts in cement pastes: Mechanistic insights and simplified modeling, Cem. Concr. Res. 199 (2026) 108050.https://doi.org/10.1016/j.cemconres.2025.108050