Experimental investigation of the mechanisms by which LiNO{sub 3} is effective against ASR

Journal Article · Thu Apr 15 04:00:00 EDT 2010 · Cement and Concrete Research

DOI:https://doi.org/10.1016/j.cemconres.2009.09.022· OSTI ID:21344754

Tremblay, C ^[1]; Fournier, B ^[1]; Thomas, M D ^[2]; Folliard, K J ^[3]

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1. Departement de geologie et de genie geologique, Universite Laval, Quebec, QC, G1K 7P4 (Canada)
2. Department of Civil Engineering, University of New Brunswick, Fredericton, NB, E3B 5A3 (Canada)
3. Department of Civil Engineering, University of Texas, Austin, TX 78712 (United States)

Various series of experiments were carried out on cements pastes, concretes made with a variety of reactive aggregates, composite specimens made of cement paste and reactive aggregate particles, and a variety of reactive natural aggregates and mineral phases immersed in various Li-bearing solutions. The main objective was to determine which mechanisms(s) better explain(s) the effectiveness of LiNO{sub 3} against ASR and variations in this effectiveness as well with the type of reactive aggregate to counteract. The principal conclusions are the following: (1), the pH in the concrete pore solution does not significantly decrease in the presence of LiNO{sub 3}; (2), the concentration of silica in the pore solution is always low and not affected by the presence of LiNO{sub 3}, which does not support the mechanism relating to higher solubility of silica in the presence of lithium; (3), the only reaction product observed in the LiNO{sub 3}-bearing concretes looks like classical ASR gel and its abundance is proportional to concrete expansion, thus is likely expansive while likely containing lithium; this does not support the mechanisms relating to formation of a non or less expansive Si-Li crystalline product or amorphous gel; (4), early-formed reaction products coating the reactive silica grains or aggregate particles, which could act as a physical barrier against further chemical attack of silica, were not observed in the LiNO{sub 3}-bearing concretes, but only for a number of reactive materials after immersion in 1 N LiOH at 350 deg. C in the autoclave (also at 80 deg. C for obsidian); (5), higher chemical stability of silica due to another reason than pH reduction or early formation of a protective coating over the reactive phases, is the mechanism among those considered in this study that better explains the effectiveness of LiNO{sub 3} against ASR.

• OSTI ID: 21344754
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 4 Vol. 40; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALI METAL COMPOUNDS
AUTOCLAVES
BUILDING MATERIALS
CEMENTS
COLLOIDS
CONCRETES
DISPERSIONS
EXPANSION
GELS
HOMOGENEOUS MIXTURES
HYDROGEN COMPOUNDS
HYDROXIDES
LITHIUM COMPOUNDS
LITHIUM HYDROXIDES
LITHIUM NITRATES
MATERIALS
MINERALS
MIXTURES
NITRATES
NITROGEN COMPOUNDS
OXIDE MINERALS
OXYGEN COMPOUNDS
PH VALUE
SILICA
SOLUBILITY
SOLUTIONS
STABILITY
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K