Electromigration of Li ions into cementitious materials as observed by NMR

Author(s): S. Venglovska, L. Pel, O.C.G. Adan
Paper category: Proceedings
Book title: Proceedings of the International RILEM Conference on Materials, Systems and Structures in Civil Engineering Conference segment on Electrochemistry in Civil Engineering
Editor(s): Lisbeth M. Ottosen
ISBN: 978-2-35158-176-6
e-ISBN: 978-2-35158-177-3
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 142-151
Total Pages: 10
Language : English

Abstract: Alkali-silica reaction (ASR) is a chemical reaction between the hydroxyl ions present in the pore solution and reactive silica. An efficient method to prevent ASR is by introducing Li ions into the system which will form a non-expansive gel. LiOH is the most efficient salt to inhibit long-term ASR expansion. The most effective way to drive Li into a sample is by electromigration. However, previous investigations did not provide specific information that can reveal and describe the lithium transport mechanism under an electric field gradient. We developed a numerical model that can describe the lithium ions transport mechanism in concrete. To verify the model, we have measured the Li profiles non-destructively by Nuclear Magnetic Resonance (NMR). This NMR method gives us the possibility for real-time monitoring of transport processes during migration experiments. In particular, it was found that significant amount of lithium ions introduced into the mortar are removed from the pore solution due to binding to the cement matrix during the first days of the experiment. Based on the obtained experimental data we propose a physical model for the lithium transport process during electromigration in mortar and predictions are made on the effectivity.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00