Alteration of alkali reactive aggregates autoclaved in different alkali solutions and application to alkali-aggregate reaction in concrete (II) expansion and microstructure of concrete microbar

Journal Article · Thu Jun 15 04:00:00 EDT 2006 · Cement and Concrete Research

OSTI ID:20871561

Duyou, Lu ^[1]; Laibao, Mei ^[1]; Zhongzi, Xu ^[1]; Mingshu, Tang ^[1]; Xiangyin, Mo ^[2]; Fournier, Benoit ^[3]

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1. College of Materials Science and Engineering, Nanjing University of Technology, 5 New Model Road, Nanjing, 210009 (China)
2. Analysis and Test Central, Nanjing Normal University, 122 Ninghai Road, Nanjing, 210097 (China)
3. ICON/CANMET, Natural Resources Canada, 405 Rochester Street, Ottawa, ON, K1A 0G1 (Canada)

The effect of the type of alkalis on the expansion behavior of concrete microbars containing typical aggregate with alkali-silica reactivity and alkali-carbonate reactivity was studied. The results verified that: (1) at the same molar concentration, sodium has the strongest contribution to expansion due to both ASR and ACR, followed by potassium and lithium; (2) sufficient LiOH can completely suppress expansion due to ASR whereas it can induce expansion due to ACR. It is possible to use the duplex effect of LiOH on ASR and ACR to clarify the ACR contribution when ASR and ACR may coexist. It has been shown that a small amount of dolomite in the fine-grained siliceous Spratt limestone, which has always been used as a reference aggregate for high alkali-silica reactivity, might dedolomitize in alkaline environment and contribute to the expansion. That is to say, Spratt limestone may exhibit both alkali-silica and alkali-carbonate reactivity, although alkali-silica reactivity is predominant. Microstructural study suggested that the mechanism in which lithium controls ASR expansion is mainly due to the favorable formation of lithium-containing less-expansive product around aggregate particles and the protection of the reactive aggregate from further attack by alkalis by the lithium-containing product layer.

• OSTI ID: 20871561
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 6 Vol. 36; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBONATES
CONCRETES
DOLOMITE
EXPANSION
LIMESTONE
LITHIUM
LITHIUM HYDROXIDES
MICROSTRUCTURE
POTASSIUM
REACTIVITY
SILICA
SODIUM
SOLUTIONS