Informace o publikaci
Effect of monocarboaluminate carbonation on mechanical properties and microstructure of lime-metakaolin mortars
| Autoři | |
|---|---|
| Rok publikování | 2025 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | CONSTRUCTION AND BUILDING MATERIALS |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | https://www.sciencedirect.com/science/article/pii/S095006182503185X?via%3Dihub#ack0005 |
| Doi | https://doi.org/10.1016/j.conbuildmat.2025.143034 |
| Klíčová slova | Monocarboaluminate; Carbonation; Metakaolin; Vaterite; Aragonite; Aluminum hydroxide |
| Popis | In order to improve the properties of fresh and hardened lime mortars, hydraulic or pozzolanic materials have been added to air lime since ancient times. It has been observed through laboratory research and in practice that some lime-pozzolan mortars, especially lime-metakaolin mortars, deteriorate in their properties over time. Although the instability of calcium aluminate hydrates in an alkaline environment has been the main explanation for this deterioration, it can be assumed that the carbonation of the monocarboaluminate also has a significant influence, as confirmed in this paper. The consequences of carbonation of lime-metakaolin mortars with five different types of metakaolin in three doses, with the aim of confirming the carbonation products of monocarboaluminate and determining the influence of the metakaolin composition and its dose on the formation of monocarboaluminate were investigated in the framework of an experimental analysis. The carbonation of monocarboaluminate was confirmed with the formation of metastable forms of calcium carbonate (aragonite and vaterite) and cryptocrystalline aluminum hydroxide, identified mainly by X-ray diffraction analysis, thermogravimetry, 27Al MAS NMR spectroscopy and scanning electron microscopy. As a result of the carbonation of monocarboaluminate, the porosity of the mortars increased because the reaction products have a smaller molar volume than the reactants, resulting in a decrease in flexural and compressive strength. Metakaolin with a higher amorphous Al2O3 content than 29 % may present a risk of deterioration in the properties of lime-metakaolin mortars. |