SciELO - Scientific Electronic Library Online

 
vol.64A greener method towards the synthesis of 1,3-diarylimidazolium tetrafluoroboratesNucleation, melting behaviour and mechanical properties of poly(L-lactic acid) affected by the addition of N, N'-bis(benzoyl) suberic acid dihydrazide índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados

Articulo

Indicadores

Links relacionados

  • En proceso de indezaciónCitado por Google
  • En proceso de indezaciónSimilares en Google

Compartir


South African Journal of Chemistry

versión On-line ISSN 1996-840X
versión impresa ISSN 0379-4350

S.Afr.j.chem. (Online) vol.64  Durban  2011

 

RESEARCH ARTICLE

 

Chloride-binding effect of blast furnace slag in cement pastes containing added chlorides

 

 

J.H. PotgieterI; D.J. DelportII, *; S. VerrynIII; S.S. Potgieter-VermaakIV

IChemistry and Materials Division, School of Biology, Chemistry and Health Sciences, Manchester Metropolitan University, All Saints Campus, Oxford Road, Manchester, Ml 5GD, UK
IIDepartment of Chemical & Metallurgical Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
IIIDepartment of Geological Sciences, University of Pretoria, Lynnwood Road, Brooklyn, Pretoria, 0002, South Africa
IVDivision of Chemistry & Environmental Science, School of Science & the Environment, Manchester Metropolitan University, All Saints Campus, Oxford Road, Manchester, Ml 5GD, UK

 

 


ABSTRACT

Corrosion of rebar in concrete is commonly associated with, and to a large degree influenced by, the free chloride concentration in the pore water. It is standard industry practice to add various mineral admixtures such as pulverised fuel ash (PFA), or fly ash, ground granulated blast furnace slag (GGBS) and silica fume (SF), to concrete mixtures to increase the corrosion resistance of the reinforcement in the matrix and its subsequent design life span. Various investigations have reported on the effect of mineral admixtures and additions on chloride binding in cementitious matrices, and the current study contributes further to knowledge in this field. Unlike previous investigations, this study attempted to make a clear distinction between the contributions of the two components in a blended cement consisting of ordinary Portland cement (OPC) and ground blast furnace slag (BFS). These contributions of each component have been quantified. Relationships between the total amount of chloride bound, the level of BFS additions, and the levels of initial chloride content present in the matrix were determined. It was found that the OPC/BFS blended cement with partial BFS replacements of up to 50 % displayed a lower binding capacity than that of the OPC on its own. This observation was derived based on the assumption that the OPC and slag reactions were treated as competing and equivalent and did not take any potential time delays into account, nor the degree of cement hydration. The chloride-binding efficiency by the BFS is dependent on both the BFS partial replacement addition level as well as the initial amount of chloride present in the matrix. It is shown that both the OPC and BFS contribute to chloride binding in cement pastes, depending on the amount ofBFS that replace the OPC component in the matrix.

Keywords: Chloride binding, granulated blast furnace slag, pore solution, permeability, corrosion


 

 

Full text available only in pdf format.

 

Acknowledgements

The authors express their gratitude to the NRF (National Research Foundation) for financial assistance and Tshwane University of Technology (TUT) for equipment and facilities to conduct the work.

 

References

1 P. Brown and J. Bothe (Jr), Cem. and Concr. Res., 2004, 34, 1549-1553.         [ Links ]

2 M. Siegward, J.F. Lyness and W. Cousins, Mag. Concr. Res, 2003, 55, 41-52.         [ Links ]

3 A.K. Suryavanshi, J.D. Scantlebury and S.B. Lyon, Cem. Concr. Res. 26, 1996, 263-281.         [ Links ]

4 U.A. Birnin-Yauri and F.P. Classer, Cemento, 1991, 88, 151-157.         [ Links ]

5 K. Tuutti, Swedish Cem. Concr. Res. Institute (CBI), 1982, 4(82), 263.         [ Links ]

6 J. Tritthart, Cem. Concr. Res. 1989a, 19, 586-594.         [ Links ]

7 J. Tritthart, Cem. Concr. Res. 1989b, 19, 683-691.         [ Links ]

8 C.L. Page and O. Vennesland, Mat. Struct. 16, 1983, 19-25.         [ Links ]

9 L. Tang and L. Nilsson, Cem. Concr. Res, 1992, 23, 247-253.         [ Links ]

10 A.K. Kalinichev and R.J. Kirkpatrick, Chem. Mater, 2002, 42, 3539-3549.         [ Links ]

11 M. Papadakis, M.N. Fardis and C.G. Vayenas, Chem. Eng. Sci., 1995, 51(4), 505-513.         [ Links ]

12 C.J. Pereira and L.L. Hegedus, 8th Intl. Symp. Chem. Reaction eng. Publication series, 1984, 87 427.         [ Links ]

13 K. Byfors, M. Hannson and J. Tritthart, Cem. Concr. Res., 1986, 25, 760-770.         [ Links ]

14 R. Luo, C Wang and X. Huang, Cem. Concr. Res, 33, 2003, 1-7.         [ Links ]

15 R.Huang and C.C. Yang, Cem. Concr. Res, 1997, 19, 131.         [ Links ]

16 H. Hirao and S. Yokoyama, Proceedings of the 11th International Congress on the Chemistry of Cement (ICCC), Durban, South Africa, 11-16 May.         [ Links ]

17 C. Arya and Y. Xu, Cem. Concr. Res., 1995, 25(4), 893-902.         [ Links ]

18 K.Y. Yeau and E.Y. Kim, Cem. Concr. Res., 2004, 35, 1391-1399.         [ Links ]

19 M. Kawamura, O. Kayyaliand M.N. Haque, Cem. Concr. Res., 1988, 18, 763-773.         [ Links ]

20 K.S. Mishra, Roads & Bridg., 2001, 1, 18-21.         [ Links ]

21 R.K. Dhir, M.A.K. El-Mohr and T.D. Dyer, Cem. Concr. Res., 1996, 26(12), 1767-1773.         [ Links ]

22 S. Diamond, Cem. Concr. Aggregates, 1986, 8, 97-102.         [ Links ]

23 H. Zibara, R.D. Hooton, M.D.A. Thomas and K. Stanish, Cem. Concr. Res., 2008, 38, 422-426.         [ Links ]

24 K. Norrish and J.T. Hutton, Geochim. Cosmochim. Acta, 1969, 33, 431-453.         [ Links ]

 

 

Received 8 June 2010
Revised 28 May 2011
Accepted 1 July 2011

 

 

* To whom correspondence should be addressed. E-mail: delportd@tut.ac.za

Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons