セメント系材料へのCO₂固定量を「炭素同位体比」で正確に判定 ―大気の影響を排除し化石燃料由来CO₂の固定量を定量化する新手法を開発―

2026-06-05 東京大学

同位体分別の概念図

＜関連情報＞

• https://www.t.u-tokyo.ac.jp/press/pr2026-06-05-001
• https://www.sciencedirect.com/science/article/pii/S0008884626001602

炭素同位体測定を用いたセメント系材料中の化石由来CO₂の隔離量および大気汚染量の定量化 Quantification of sequestered fossil-derived CO₂ in cementitious materials and its atmospheric contamination using carbon isotope measurements

Ippei Maruyama, Ryusei Igami, Ryo Kurihara, Masayo Minami, Hiroshi A. Takahashi, Abudushalamu Aili

Cement and Concrete Research  Available online: 2 June 2026

DOI:https://doi.org/10.1016/j.cemconres.2026.108290

Abstract

Carbonation of cementitious materials has attracted increasing attention as a potential approach for CO₂ fixation. However, quantitative evaluation of the amount of CO₂ fixed from a designated source under accelerated carbonation conditions remains challenging, because atmospheric CO₂ mixing may occur. In this study, carbonation experiments were conducted on well-hydrated cement paste powders under controlled relative humidity conditions using fossil-derived CO₂, and carbon uptake and isotopic compositions were investigated using combined ¹³C and ¹⁴C analyses. The results show that atmospheric CO₂ can contribute significantly to the isotopic composition of the fixed carbon in the samples. Two approaches were proposed to quantify this atmospheric contribution, which yield contamination estimates of comparable magnitude. Based on the estimated atmospheric mixing, a practical framework is established to quantify the amount of CO₂ fixed from the ¹⁴C-free fossil-derived source gas. The proposed approach enables source-specific evaluation of CO₂ fixation in cementitious materials and supports quantitative assessment and labeling of carbon-captured materials.