New observations on the mechanism of lithium nitrate against alkali silica reaction (ASR)
- Department of Civil Engineering, University of New Brunswick, Fredericton, NB (Canada)
- Concrete Durability Center, The University of Texas at Austin, TX (United States)
- Concrete Technology Program, CANMET-MTL, Ottawa, ON (Canada)
In the current study, in order to elucidate the mechanisms for the favorable effects of lithium nitrate in controlling alkali silica reaction (ASR), vycor glass disk immersion specimens and glass disk-cement paste sandwich specimens were prepared and examined by XRD, SEM and Laser Ablation Induction Coupled Plasma Mass Spectrometry (LA-ICP-MS). Results showed that when glass disk was immersed in only NaOH solution, the glass was attacked by hydroxyl ions but no solid reaction product was found, thus the presence of calcium was essential for the formation of ASR gel. In the presence of lithium, the glass surface was covered by a thick layer of Li-Si crystal. With the addition of Ca(OH){sub 2}, the glass surface was completely covered by Li-Si crystal and a lithium-bearing low Ca-Na-(K)-Si gel. These two phases either form a dense matrix with Li-Si crystal serving as the framework, and the gel filling in the void space, or the Li-Si crystal serving as the foundation to completely cover the entire reactive SiO{sub 2} surface, and the gel sitting on top of these crystal particles. Hence, the suppressive effects of LiNO{sub 3} were attributed to the formation of a layer of Li-Si crystals intimately at the reactive SiO{sub 2} particle surface and the formation of Li-bearing low-Ca ASR gel products. The Li-bearing low-Ca ASR gels may have a dense and rigid structure, thus having low capacity to absorb moisture from the surrounding paste, and exhibiting a non-swelling property.
- OSTI ID:
- 21344739
- Journal Information:
- Cement and Concrete Research, Vol. 40, Issue 1; Other Information: DOI: 10.1016/j.cemconres.2009.07.017; PII: S0008-8846(09)00173-2; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0008-8846
- Country of Publication:
- United States
- Language:
- English
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ABLATION
CALCIUM HYDROXIDES
CEMENTS
CRYSTALS
GELS
GLASS
ICP MASS SPECTROSCOPY
LITHIUM
LITHIUM NITRATES
SCANNING ELECTRON MICROSCOPY
SILICA
SILICON OXIDES
SODIUM HYDROXIDES
SWELLING
VOIDS
VYCOR
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
ALKALI METALS
ALKALINE EARTH METAL COMPOUNDS
BUILDING MATERIALS
CALCIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COLLOIDS
DEFORMATION
DIFFRACTION
DISPERSIONS
ELECTRON MICROSCOPY
ELEMENTS
HYDROGEN COMPOUNDS
HYDROXIDES
LITHIUM COMPOUNDS
MASS SPECTROSCOPY
MATERIALS
METALS
MICROSCOPY
MINERALS
NITRATES
NITROGEN COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SCATTERING
SILICON COMPOUNDS
SODIUM COMPOUNDS
SPECTROSCOPY