Investigation of the carbonation mechanism of \{CH\} and C-S-H in terms of kinetics, microstructure changes and moisture properties

Antoine Morandeau (1) , Mickaël Thiery (2) , Patrick Dangla (3)

1 IFSTTAR/MAST - Département Matériaux et Structures
2 IFSTTAR/MAT - Département Matériaux
3 Physique des milieux poreux

The purpose of this article is to investigate the carbonation mechanism of CH and C-S-H within type-I cement-based materials in terms of kinetics, microstructure changes and water released from hydrates during carbonation. Carbonation tests were performed under accelerated conditions (10% CO2, 25 °C and 65 ± 5% RH). Carbonation profiles were assessed by destructive and non-destructive methods such as phenolphthalein spray test, thermogravimetric analysis, and mercury intrusion porosimetry (destructive), as well as gamma-ray attenuation (non-destructive). Carbonation penetration was carried out at different ages from 1 to 16 weeks of CO2 exposure on cement pastes of 0.45 and 0.6 w/c, as well as on mortar specimens (w/c = 0.50 and s/c = 2). Combining experimental results allowed us to improve the understanding of C-S-H and CH carbonation mechanism. The variation of molar volume of C-S-H during carbonation was identified and a quantification of the amount of water released during CH and C-S-H carbonation was performed.

Mots clés: Carbonation (C); Calcium-silicate-hydrate (C-S-H) (B); Microstructure (B); Portland cement (D); Calcium hydroxide (B)

Domaines: Génie civil

Antoine Morandeau, Mickaël Thiery, Patrick Dangla. Investigation of the carbonation mechanism of \{CH\} and C-S-H in terms of kinetics, microstructure changes and moisture properties. Cement and Concrete Research, 2014, 56, pp.153 - 170. ⟨10.1016/j.cemconres.2013.11.015⟩. ⟨hal-00922073⟩