Solubility Behavior of the Hydration Products in the Pore Solution of Hydrated Cement Pastes

Abstract:

The concentrations of Ca, Al, Si, Na, K, SO42- and pH value in the pore solution of Portland cement were measured during the first 28 days of hydration at room temperature. A thermodynamic analysis of the elemental concentrations was used to predict saturation indices of various solid phases known to form in normal cement system. During the first 4 h the composition of pore solution is dominated by K+, Na+, SO42-and OH-. Large and rapid changes in the concentrations of Ca2+, SO42- and hydroxyl occurred between 4 h and 24 h, and thereafter the pore solution is essentially one of alkali hydroxides. Portlandite and calcium monosulfoaluminate was slightly supersaturated after the first few hours. Saturation indices calculations for ettringite and C-S-H indicate the high levels of supersaturation until 28 days.

• Periodical: Key Engineering Materials (Volume 539)
• Pages: 189-194
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.539.189
• Online since: January 2013
• Authors: Wu Yao, Man Jian Wu
• Keywords: Hydrated Cement Paste, Pore Solution, Solubility

References

[1] P.C. Hewlett, Lea's Chemistry of Cement and Concrete. 4th ed., Oxford, Elsevier, 1998.

[2] T. Josef and H. Frank, Pore solution analysis of cement pastes and nanostructural investigations of hydrated C3S. Cement and Concrete Research, 33 (2003) 1063-1070.

DOI: 10.1016/s0008-8846(03)00011-5

[3] L. Barbara, Thermodynamic equilibrium calculations in cementitious systems, Materials and Structures, 43 (2010) 1413-1433.

[4] J.R. Eric, Problems and approaches to the prediction of the chemical composition in cement/water systems. Waste Management, 12 (1992) 221-239.

DOI: 10.1016/0956-053x(92)90050-s

[5] R. S. Barneyback and S. Diamond, Expression and analysis of pore fluids from hardened cement pastes and mortars, Cem. Concr. Res. 11 (1981) 279-285.

DOI: 10.1016/0008-8846(81)90069-7

[6] Mindess Sidney, Concrete, 1st ed., Prentice Hall, Englewood Cliffs, USA, 1981.

[7] D. K. Nordstrom, Groundwater Geochemistry, Springer-Verlag, The Netherlands, 2005.

[8] R. David, J. Jeffrey, B.J. Thomas, Solubility behavior of Ca, S, Al, and Si bearing solid phases in Porland cement pore solutions as a function of hydration time, Cem. Concr. Res. 32 (2002) 1663.

DOI: 10.1016/s0008-8846(02)00855-4

[9] D.L. Parkhurst, User's guide to PHREEQC- a computer program for speciation, reaction-path, advective transport, and inverse geochemical calculations, Water-Resources Investigations Report 95-4227,United States Geological Survey, Lakewood, CO, 1995.

DOI: 10.3133/wri954227

[10] K. Andersson，B. Allard，M. Bengtsson，B. Magnusson. Chemical composition of cement pore solution. Cement And Concrete Research，19 (1989) 327-332.

DOI: 10.1016/0008-8846(89)90022-7

[11] L. Barbara and W. Frank, Thermodynamic modeling of the hydration of Portland cement. Cement and Concrete Research，36 (2006) 209-226.

DOI: 10.1016/j.cemconres.2005.03.001

[12] H.M. Jennings. Aqueous solubility relationships for two types of calcium silicate hydrate. Journal of the American Ceramic Society，69 (1986) 614-618.

DOI: 10.1111/j.1151-2916.1986.tb04818.x

[13] E.M. Gartner，H. M. Jennings. Thermodynamics of Calcium Silicate Hydrates and Their Solutions. Journal of the American Ceramic Society，70 (1987) 743-749.

DOI: 10.1111/j.1151-2916.1987.tb04874.x

[14] E.J. Reardon. An ion interaction model for the determination of chemical equilibria in cement/water systems. Cement and Concrete Research，20 (1990) 175-192.

DOI: 10.1016/0008-8846(90)90070-e

[15] U.R. Berner. Evolution of pore water chemistry during degradation of cement in a radioactive waste repository environment. Waste Management，12 (1992) 201-219.

DOI: 10.1016/0956-053x(92)90049-o

[16] S. Börjesson, A. Emrén, C. Ekberg. A thermodynamic model for the calcium silicate hydrate gel, modeled as a non-ideal binary solid solution. Cement and Concrete Research, 11 (1997) 1649-1657

DOI: 10.1016/s0008-8846(97)00149-x

[17] M. Rahman, S. Nagasaki, and S. Tanaka. A model for dissolution of CaO-SiO2-H2O gel at Ca/Si > 1. Cement and Concrete Research, 29 (1999) 1091-1097.

DOI: 10.1016/s0008-8846(99)00092-7

[18] C.S. Walker, D. Savage, M. Tyrer. Non-ideal solid solution aqueous solution modeling of synthetic calcium silicate hydrate. Cement and Concrete Research, 37 (2007) 502-511.

DOI: 10.1016/j.cemconres.2006.12.002

[19] M. Kersten. Aqueous Solubility Diagrams for Cementitious Waste Stabilization Systems: I. The C-S-H Solid-Solution System. Environmental Science & Technology, 30 (1996) 2286-2293.

DOI: 10.1021/es950681b

[20] D.A. Kulik, M. Kersten. Aqueous solubility diagrams for cementitious waste stabilization systems: II, end-member stoichiometries of ideal calcium silicate hydrate solid solutions. Journal of the American Ceramic Society, 84 (2001) 3017-3026.

DOI: 10.1111/j.1151-2916.2001.tb01130.x