RELATION BETWEEN CONCRETE LEACHABILITY AND pH USING STATISTICAL APPROACH

Attack of external water to concrete results in the degradation of cement and changes the concrete pore water and solid phase composition. The leaching behaviour of cement-based products have been shown to be similar after assessing the leaching characteristics by means of a pH dependence leaching test. The paper is focused on the investigation of the leachability of the concrete samples of different composition due to distilled water and its relation to pH. Si, Ca, Al, Fe and Mn ions leached out from the cement matrix were measured after each of fives experimental cycles. Three sets of samples were studied: without fly ash, and containing coal fly as cement replacement (5 wt. % and 10% wt. respectively). Statistical methods were used for the intensity and course of deterioration assessment regarding a dependency of Si/pH, Ca/pH Al/pH and Fe/pH and Mn/pH for each type of samples. The correlation among leaching processes according to type of concrete were also statistically studied.

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    [1]  Adenot F. and Buil M., 1992. Modelling of the corrosion of the cement paste by deionized water, Cem. Concr. Res. 22, 259-272.

    [2]  Carde C. and Francois R., 1999. Modelling the loss of strength and porosity increase due to the leaching of cement pastes, Cem. Concr. Compos. 21, 181-188.

    [3]  Dodge, Y. 2003. The Oxford Dictionary of Statistical Terms, OUP Oxford.

    [4]  Estokova, A., Ondrejka Harbulakova, V., Luptakova, A., Stevulova, N., Palascakova, L., Repka, M. 2013. Analysis of the selected characteristics changes of cement composites exposed to the sulphate environment, Chemical Engineering Transactions. Vol. 32, 1597-1602.

    [5]  Hitomi T., available at: http://www.spring8.or.jp/pdf/en/res_fro/05/131-132.pdf [access: 28 April 2015].

    [6]  Ikeda M. et al., 2004. Influence of type of cement on Ca leaching from concrete using experimental acceleration method, 29th conference on our world in concrete and structures, 25-26 august, Singapore.

    [7]  Kamali S. et al., 2003. Modelling the leaching kinetics of cement based materials – influence of materials and environment, Cem. Concr. Compos.25, 451-458.

    [8]  Kosmatka H. et al., 2003. Design and Control of Concrete Mixtures, 14^th ed., Engineering Bulletin 001, PCA, USA.

    [9]  Kreyszig, E. 2011. Advanced Engineering Mathematics, John Wiley and sons, 10^th edition, 2011.

 [10]  Lamond J. F. and Pielert J. H., 2006. Significance of tests and properties of concrete and concrete-making materials, ASTM International, New York.

 [11]  Mainguy M. et al., 2000. Modelling of leaching in pure cement paste and mortar, Cem. Concr. Res. 30, 83-90.

 [12]  Moranville M. et al., 2004. Physicochemical equilibria of cement-based materials in aggressive environments – experiment and modeling, Cem. Concr.Res. 34,
1569-1578.

1. Ondrejka Harbulakova, V., Purcz, P., Estokova, A., Luptakova, A., Repka, M. 2015. Using a Statistical Method for the Concrete Deterioration Assessment in Sulphate Environment , Chemical Engineering Transaction, Vol.43.
2. Ondrejka Harbulakova, V., Luptakova, A., Estokova, A., Stevulova, N., Palascakova, L. 2012. A Using of Coal Fly Ash in Concrete Materials and the Durability of Materials Testing Considering the Resource Optimization, Visions for the Future of Housing : Mega Cities : proceedings of the 38th IAHS World Congress: Istanbul, Turkey, April 16-19, Technical University, 959-964.

 [15]  Rozière, E. et al., 2009. Durability of concrete exposed to leaching and external sulphate attacks Cem. Concr. Res 39, 1188-1198.

 [16]  SCA, 2002. Slag cement in concrete, no. 11, Slag Cement association available at: http://www.slagcement.org/pdf/no11%20Slag%20Cement%20and%20Fly%20Ash.pdf [access: 28 April 2015].