AFm phase
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An AFm phase is an "alumina, ferric oxide, monosulfate" phase, or aluminate ferrite monosulfate, or Al2O3, Fe2O3 mono, in cement chemist notation. AFm phases are important in the hydration of hydraulic cements.
They are crystalline hydrates with general, simplified formula 3CaO·(Al,Fe)2O3·CaSO4·nH2O where n may be comprised between 13 and 19 water molecules.[1]
They form inter alia when tricalcium aluminate (C3A: 3CaO·Al2O3) reacts with dissolved calcium sulfate (CaSO4).
See also[]
- Concrete degradation#Chloride attack
- Layered double hydroxides (LDH)
- Friedel's salt
- Ettringite (AFt)
- Pitting corrosion of rebar induced by chloride attack
References[]
- ^ Matschei, T.; Lothenbach, B.; Glasser, F. P. (2007-02-01). "The AFm phase in Portland cement". Cement and Concrete Research. 37 (2): 118–130. doi:10.1016/j.cemconres.2006.10.010. ISSN 0008-8846. Retrieved 2022-02-10.
Further readings[]
- Hirao, Hiroshi; Yamada, Kazuo; Takahashi, Haruka; Zibara, Hassan (2005). "Chloride binding of cement estimated by binding isotherms of hydrates". Journal of Advanced Concrete Technology. 3 (1): 77–84. doi:10.3151/jact.3.77. eISSN 1347-3913. ISSN 1346-8014. Retrieved 2022-02-19.
- Galan, Isabel; Glasser, Fredrik P. (2015-02-01). "Chloride in cement". Advances in Cement Research. 27 (2): 63–97. doi:10.1680/adcr.13.00067. eISSN 1751-7605. ISSN 0951-7197. Retrieved 2022-02-19.
- Baquerizo, Luis G.; Matschei, Thomas; Scrivener, Karen L.; Saeidpour, Mahsa; Wadsö, Lars (2015-07-01). "Hydration states of AFm cement phases". Cement and Concrete Research. 73: 143–157. doi:10.1016/j.cemconres.2015.02.011. ISSN 0008-8846. Retrieved 2022-02-10.
- Feng, Pan; Miao, Changwen; Bullard, Jeffrey W. (2016-03-01). R. Riman (ed.). "Factors influencing the stability of AFm and AFt in the Ca – Al – S – O – H System at 25 °C". Journal of the American Ceramic Society. 99 (3): 1031–1041. doi:10.1111/jace.13971. ISSN 1551-2916. Retrieved 2022-02-10.
- Nedyalkova, Latina; Tits, Jan; Renaudin, Guillaume; Wieland, Erich; Mäder, Urs; Lothenbach, Barbara (2022-02-15). "Mechanisms and thermodynamic modelling of iodide sorption on AFm phases". Journal of Colloid and Interface Science. 608: 683–691. doi:10.1016/j.jcis.2021.09.104. ISSN 0021-9797. Retrieved 2022-02-10.
Categories:
- Aluminium compounds
- Cement
- Concrete
- Hydrates
- Iron compounds
- Iron(III) compounds
- Silicates
- Sulfate minerals
- Sulfates