Materiales de Construcción, Vol 64, No 316 (2014)

Evolution of pyrrhotite oxidation in aggregates for concrete

I. Oliveira
Universidad Politécnica de Cataluña, Spain

S. H.P. Cavalaro
Universidad Politécnica de Cataluña, Spain

A. Aguado
Universidad Politécnica de Cataluña, Spain


Rocks containing pyrrhotite bands are sometimes used to produce concrete. These rocks oxidize and produce long-term expansive reactions that damage concrete structures, leading to important economic and risk related repercussions. The present study analyses several aspects that affect the oxidation process of the aggregate such as the existence of preferential paths for the entrance of the oxidizing agent and the conversion process of the chemical elements involved in the reaction. For that, host rock samples containing pyrrhotite were investigated by scanning electron microscopy and energy dispersive spectroscopy. The results shows that the pyrrhotite appears in bands that create planes of weakness and present cracks that serve as preferential paths for the entrance of oxygen. Furthermore, a new representation is proposed for the oxidation process.


Iron sulfide; Oxidation; Aggregate; Internal sulfate attack; Dam

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1. Cárdenes, V.; García-Guinea, J.; Monterroso, C.; de la Horra, R. (2008) Protocol for assessing the effectiveness of protective coatings for roofing slate. Mater. Construc., 58 [289–290], 263–279.

2. Aguado, A.; Agulló, L.; Casanova, I.; López, C.M. (1998) Estudio de fenómenos expansivos en presas de hormigón. De la micro a la macro estructura. Comité Español de Grandes Presas. Premio José Torán.

3. Casanova, I.; Agulló, L.; Aguado, A. (1996) Aggregate expansivity due to sulfide oxidation – I. Reaction system and rate model. Cem. Concr. Res., 26, 993–998.

4. Czerewko, M.A.; Cripps, J.C.; Reid, J.M.; Duffell, C.G. (2003) Sulfur species in geological minerals – sources and quantification. Cem. Concr. Res., 25, 657–671.

5. Gomides, J.M.J. (2009) Investigação de agregados contendo sulfetos e seus efeitos sobre a durabilidade do concreto. PhD Tesis (in portuguese), Porto Alegre.

6. Lee, H.; Cody, R.D.; Cody, A.M.; Spry, P.G. (2005) The formation and role of ettringite in Iowa highway concrete deterioration. Cem. Concr. Res., 35, 332–343.

7. Oliveira, I.; Cavalaro, S.H.P.; Aguado, A. (2013) New Unreacted-Core Model to Predict Pyrrhotite Oxidation in Concrete Dams. J. Mater. Civ. Eng., 25 [3], 372–381.

8. Oliveira, I.; Cavalaro, S.H.P.; Aguado, A. (2013) New kinetic model to quantify the internal sulfate attack in concrete. Cem. Concr. Res., 43, 95–104.

9. Becker, M. (2004) The mineralogy and crystallography of pyrrhotite from selected nickel and PGE ore deposits and its effects on flotation performance. PhD Tesis, University of Pretoria.

10. Chinchon, J.S.; Ayora, C.; Aguado, A.; Guirado, F. (1995) Influence of weathering of iron sulfides contained in aggregates on concrete durability. Cem. Concr. Res., 25, 1264–1272.

11. Janzen, M.P.; Nicholson, R.V.; Scharer, J.N. (2000) Pyrrhotite reactions kinetics: reaction rates for oxidation by oxygen, ferric iron, and for nonoxidative dissolution. Geochimica et Cosmochimica Acta, 64, 1511–1522.

12. Steger, H.F. (1982) Oxidation of sulfide minerals VII. Effect of temperature and relative humidity on the oxidation of the pyrrhotite. Chem. Geol., 35, 281–295.

13. Tagnit-Hamou, A.; Saric-Coric, M.; Rivard, P. (2005) Internal deterioration of concrete by the oxidation of pyrrhotitic aggregates. Cem. Concr. Res., 35, 99–107.

14. Schmidt, T.; Leemann, A.; Gallucci, E.; Scrivener, K.L. (2009) Microstructural investigations of iron sulfide degradation in concrete. Int. Baustofftagung (IBAUSIL), Weimar, Germany, 23–26.

15. García-Guinea, J.; Cardenes, V.; Lombardero, M.; Desiloniz, M.I. (2002) Determination of iron sulphides in roofing slates from the north west of Spain. Mater. Construc., 52 [266], 55–63.

16. Ayora, C.; Chinchón, S.; Aguado, A.; Guirado, F. (1998) Weathering of iron sulfides and concrete alteration: thermodynamic model and observation in dams from Central Pyreness, Spain. Cem. Concr. Res., 28, 1223–1235.

17. Mycroft, J.R.; Nesbitt, H.W.; Pratt, A.R. (1995) X-ray photoelectron and Auger electron spectroscopy of air-oxidized pyrrhotite: Distribution of oxidized species with depth. Geochimica et Cosmochimica Acta., 59, 721–733.

18. Pratt, A.R.; Muir, I.J.; Nesbitt, H.W. (1994) X-ray photoelectron and Auger electron spectroscopic studies of pyrrhotite and mechanism of air oxidation. Geochimica et Cosmochimica Acta., 58, 827–841.

19. Jones, C.F.; Lecount, S.; Smart, R.; White, T. (1992) Compositional and structural alteration of pyrrhotite surfaces in solution: XPS and XRD studies. Appl. Surf. Sci., 55, 65–85.

20. Belzile, N.; Chen, Y.; Cai, M.; Li, Y. (2004) A review on pyrrhotite oxidation. J. Geochem. Exploration., 84, 65–76.

21. Legrand, D.L.; Bancroft, G.M.; Nesbitt, H.W. (2005) Oxidation/alteration of pentlandite and pyrrhotite surfaces at pH 9.3: Part I - assignment of XPS spectra and chemical trends. Am. Mineral., 90, 1042–1054.

22. Oliveira, I.; Chinchón-Paya, S.; Aguado, A.; Chinchón, S. (2011) Pyrrhotite oxidation kinetics: host rock influence and the effect of aggregate size on a concrete dam. XIII ICCC - International Congress on Chemistry of Cement, Madrid, Spain, ISBN: 84-7292-399-7.

23. Araújo, G.S. (2008) La reacción sulfática de origen interno en presas de hormigón. Propuesta metodológica de análisis. PhD Tesis (in spanish). Universidad Politécnica de Catalunya, Barcelona.

24. Oliveira, I. (2011) Reacción sulfática interna en presas de hormigón: cinética del comportamiento. PhD Thesis. Polytechnic University of Catalunya (in Spanish), Barcelona.

25. Divet, L. (2001) Les reactions sulfatiques internes au beton. Contribution à l’etude des mecanismes de la formation differee de l’ettringite. PhD Thesis, Conservatoire National des Arts et Metiers, Paris.

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