Sulfate Attack on Pastes Made with Different C3A and C4AF Contents and Stored at 5°C

In the present work the internal sulfate attack on
pastes made from pure clinker phases was studied. Two binders were
produced: (a) a binder with 2% C3A and 18% C4AF content; (b) a
binder with 10% C3A and C4AF content each. Gypsum was used as
the sulfate bearing compound, while calcium carbonate added to
differentiate the binders produced. The phases formed were identified
by XRD analysis. The results showed that ettringite was the
deterioration phase detected in the case of the low C3A content
binder. Carbonation occurred in the specimen without calcium
carbonate addition, while portlandite was observed in the one
containing calcium carbonate. In the case of the high C3A content
binder, traces of thaumasite were detected when calcium carbonate
was not incorporated in the binder. A solid solution of thaumasite and
ettringite was found when calcium carbonate was added. The amount
of C3A had not fully reacted with sulfates, since its corresponding
peaks were detected.





References:
[1] P. Brown, and R. D. Hooton, "Ettringite and thaumasite formation in
laboratory concretes prepared using sulfate-resisting cements,” Cem.
Concr. Compos., vol. 24, pp. 361–370, 2002.
[2] N. J. Crammond, "The thaumasite form of sulfate attack in the UK,”
Cem. Concr. Compos., vol. 25, pp. 809–818, 2003.
[3] D. E. Macphee, and S. J. Barnett, "Solution properties of solids in the
ettringite – thaumasite solid solution series,” Cem. Concr. Res., vol. 34,
pp. 1591–1598, 2004.
[4] B. Tian, and M. D. Cohen, "Does gypsum formation during sulfate
attack on concrete lead to expansion?,” Cem. Concr. Res., vol. 30, pp.
117–123, 2000.
[5] M. Santhanam, M. D. Cohen, and J. Olek, "Effects of gypsum formation
on the performance of cement mortars during external sulfate attack,”
Cem. Concr. Res., vol. 33, pp. 325–332, 2003.
[6] J. Bensted, "Thaumasite – direct, woodfordite and other possible
formation routes,” Cem. Concr. Compos., vol. 25, pp. 873–877, 2003.
[7] T. Schmidt, B. Lothenbach, M. Romer, K. Scrivener, D. Rentsch, and R.
Figi, "A thermodynamic and experimental study of the conditions of
thaumasite formation,” Cem. Concr. Res., vol. 38, pp. 337–349, 2008.
[8] M. T. Blanco-Varela, J. Aguilera, and S. Martínez-Ramírez, "Effect of
cement C3A content, temperature and storage medium on thaumasite
formation in carbonated mortars,” Cem. Concr. Res., vol. 36, pp. 707–
715, 2006.
[9] J. Rose, A. Bénard, S. El Mrabet, A. Masion, I. Moulin, V. Briois, L.
Olivi, and J.-Y. Bottero, "Evolution of iron speciation during hydration
of C4AF,” Waste Manage., vol. 26, pp. 720–724, 2006.
[10] E. F. Irassar, "Sulfate attack on cementitious materials containing
limestone filler – A review,” Cem. Concr. Res., vol. 39, pp. 241–254,
2009.
[11] T. Liang, and Y. Nanru, "Hydration products of calcium aluminoferrite
in the presence of gypsum,” Cem. Concr. Res., vol. 24, pp. 150–158,
1994.
[12] V. Lilkov, O. Petrov, Y. Tzvetanova, and P. Savov, "Mössbauer, DTA
and XRD study of Portland cement blended with fly ash and silica
fume,” Constr. Build. Mater., vol. 29, pp. 33–41, 2012.
[13] B. Z. Dilnesa, B. Lothenbach, G. Le Saout, G. Renaudin, A. Mesbah, Y.
Filinchuk, A. Wichser, and E. Wieland, "Iron in carbonate containing
AFm phases,” Cem. Concr. Res., vol. 41, pp. 311–323, 2011.
[14] G. Möschner, B. Lothenbach, J. Rose, A. Ulrich, R. Figi, and R.
Kretzschmar, "Solubility of Fe-ettringite
(Ca6[Fe(OH)6]2(SO4)3·26H2O),” Geochim. Cosmochim. Ac., vol. 72, pp.
1–18, 2008.
[15] B. Z. Dilnesa, E. Wieland, B. Lothenbach, R. Dähn, and K. L. Scrivener,
"Fe-containing phases in hydrated cements,” Cem. Concr. Res., vol. 58,
pp. 45–55, 2014.
[16] B. A. Clark, and P. W. Brown, "Phases formed during hydration of
tetracalcium aluminoferrite in 1.0M magnesium sulfate solutions,” Cem.
Concr. Compos., vol. 24, pp. 331–338, 2002.
[17] G. Kakali, S. Tsivilis, E. Aggeli, and M. Bati, "Hydration products of
C3A, C3S and Portland cement in the presence of CaCO3,” Cem. Concr.
Res., vol. 30, pp. 1073–1077, 2000.
[18] T. Matschei, B. Lothenbach, and F. P. Glasser, "The role of calcium
carbonate in cement hydration,” Cem. Concr. Res., vol. 37, pp. 551–558,
2007.