Chloride binding in the CaO-SiO2-Al2O3-SO3-Na2O-CO2-H2O system for Portland cement

Title: Chloride binding in the CaO-SiO2-Al2O3-SO3-Na2O-CO2-H2O system for Portland cement
Author(s): Erik P. Nielsen, Duncan Herfort, Mette R. Geiker
Paper category : conference
Book title: International RILEM Symposium on Concrete Science and Engineering: A Tribute to Arnon Bentur
Editor(s): J. Weiss, K. Kovler, J. Marchand, and S. Mindess
Print-ISBN: None
e-ISBN: 2912143926
Publisher: RILEM Publications SARL
Publication year: 2004
Nb references: 18
Language: English

Abstract: A model for predicting the phase assemblage in hydrated Portland cements at different contents of chlorides and alkalis, including calculations of the relative contents and compositions of the phases present was described in [1,2]. Additional data on the accuracy and verification of the model is presented in this paper, including calculations of the threshold values for chloride induced corrosion as a function of cement composition. The Al2O3 and Fe2O3 contents of Portland cements are shown to have limited effect on the overall chloride binding capacity compared to the effect of alkalis, with high alkali contents significantly reducing the chloride binding capacity. Lower alkali contents, although resulting in a lower pH of the pore solution, are shown to lower the Cl/OH-ratio of the pore solution, therefore reducing the risk of corrosion. Practical applications of the model are also discussed.

Online publication: 2004-03-25
Classification: Transport
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143926.044