Chloride binding isotherm from migration and diffusion tests

Chloride binding is often described by chloride binding isotherm, which is closely related to the service life of concrete structures in chloride environments. Many methods have been proposed to determine chloride binding isotherm. Compared to other methods, chloride binding isotherms obtained directly from nonsteady-state diffusion tests seem closer to the reality. We studied the chloride binding isotherm from both nonsteady-state electrical-accelerated migration and diffusion tests at different temperatures. Twelve concrete mixes with different supplementary cementing materials and water-to-binder ratios of 0.35, 0.48 and 0.6 were cast for study. The specimens after diffusion (or migration) tests were sliced layer by layer, and acid-soluble and free chloride contents of each layer were measured. A chloride binding isotherm was obtained from one specimen. Experimental results indicated that electrical voltage had a slight effect on the chloride binding isotherm of concrete. Temperature had a positive effect on chloride binding. The higher the water-to-binder ratio was, the higher the chloride binding was.

[1]  Marta Castellote,et al.  Chloride-binding isotherms in concrete submitted to non-steady-state migration experiments , 1999 .

[2]  T. Ishida,et al.  Chloride Binding Capacity of Mortars Made with Various Portland Cements and Mineral Admixtures , 2008 .

[3]  Katrien Audenaert,et al.  Chloride binding of cement-based materials subjected to external chloride environment – A review , 2009 .

[4]  Lars-Olof Nilsson,et al.  Chloride binding capacity and binding isotherms of OPC pastes and mortars , 1993 .

[5]  Shigeyoshi Nagataki,et al.  Evaluation of the AgNO3 solution spray method for measurement of chloride penetration into hardened cementitious matrix materials , 1993 .

[6]  M. H. Roberts,et al.  Effect of calcium chloride on the durability of pre-tensioned wire in prestressed concrete , 1962 .

[7]  O. A. Kayyali,et al.  Free and water soluble chloride in concrete , 1995 .

[8]  Shigeyoshi Nagataki,et al.  Evaluation of AgNO 3 Solution Spray Method for Measurement of Chloride Penetration into Hardened Cementitious Matrix Materials , 1992 .

[9]  Anwar Khitab,et al.  Predictive model for chloride penetration through concrete , 2005 .

[10]  P. Hénocq.  Modeling of ionic interactions at the C-S-H surface. Application to CsCl and LiCl solutions in comparison with NaCl solutions , 2006 .

[11]  G. Sergi,et al.  Diffusion of chloride and hydroxyl ions in cementitious materials exposed to a saline environment , 1992 .

[12]  S. Lorente,et al.  The relation between electrokinetics and chloride transport through cement-based materials , 2008 .

[13]  E. Samson,et al.  Modeling the Effect of Temperature on Ionic Transport in Cementitious Materials , 2007 .

[14]  Nick R. Buenfeld,et al.  An investigation of experimental methods used to determine free and total chloride contents , 1996 .

[15]  Q. Yuan,et al.  Fundamental Studies on Test Methods for the Transport ofChloride Ions in Cementitious Materials. , 2009 .

[16]  Hassan Zibara,et al.  Binding of external chlorides by cement pastes , 2001 .