Experimental studies and thermodynamic modeling of the carbonation of Portland cement, metakaolin and limestone mortars
- Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 C Aarhus (Denmark)
- Laboratory for Concrete & Construction Chemistry, Swiss Federal Laboratories for Materials Science and Technology (Empa), 8600 Dübendorf (Switzerland)
- Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim 7491 (Norway)
- Aalborg Portland A/S, Cementir Holding S.p.A., 9100 Aalborg (Denmark)
The carbonation of Portland cement, metakaolin and limestone mortars has been investigated after hydration for 91 days and exposure to 1% (v/v) CO{sub 2} at 20 °C/57% RH for 280 days. The carbonation depths have been measured by phenolphthalein whereas mercury intrusion porosimetry (MIP), TGA and thermodynamic modeling have been used to study pore structure, CO{sub 2} binding capacity and phase assemblages. The Portland cement has the highest resistance to carbonation due to its highest CO{sub 2} binding capacity. The limestone blend has higher CO{sub 2} binding capacity than the metakaolin blends, whereas the better carbonation resistance of the metakaolin blends is related to their finer pore structure and lower total porosity, since the finer pores favor capillary condensation. MIP shows a coarsening of the pore threshold upon carbonation for all mortars. Overall, the CO{sub 2} binding capacity, porosity and capillary condensation are found to be the decisive parameters governing the carbonation rate.
- OSTI ID:
- 22697074
- Journal Information:
- Cement and Concrete Research, Journal Name: Cement and Concrete Research Vol. 88; ISSN 0008-8846; ISSN CCNRAI
- Country of Publication:
- United States
- Language:
- English
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