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Pro057

Effect of NaCl content in immersion solution on the decalcification of cement pastes



Author(s): P. Henocq
Paper category: workshop
Book title: Performance of cement-based materials in aggressive aqueous environments – characterization, modelling, test methods and engineering aspects
Editor(s): Nele De Belie
Print ISBN: none
e-ISBN: 978-2-35158-059-2
Publisher: RILEM Publications SARL
Pages: 61 - 72
Total Pages: 12
Language: English


Abstract: Degradation of concrete structures can be induced by the exposure to sodium chloride solutions. The penetration of chloride ions is a major cause of the corrosion of steel reinforcement. Moreover, chloride solutions have a neutral pH, which is an additional cause of degradation as the pore solution of sound material is highly basic. The decalcification of cement pastes is presented in this paper. Particularly, the effect of the NaCl content is investigated. The experimental results by microprobe analysis show a higher decalcification rate as the NaCl concentration increases. This behavior is explained by the chemical equilibrium of portlandite and, specially, by the influence of the NaCl content on the ionic activity. Experimental results on the portlandite solubility in the presence of NaCl solutions confirm the effect of sodium chloride on leaching. Modeling simulations with the numerical model STADIUM® gives reliable results in agreement with the experimental observations. Leaching on C3S pastes were also performed to validate the simulations of the decalcification.


Online publication: 2008
Publication Type: full_text
Public price (Euros): 0.00