New observations on the mechanism of lithium nitrate against alkali silica reaction (ASR)

Feng, Xiao; Thomas, M D; Bremner, T. W.; Folliard, Kevin J.; Fournier, Benoît

doi:10.1016/j.cemconres.2009.07.017

Cited by 59 publications

(27 citation statements)

References 7 publications

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“…After this, research on lithium compounds was nearly stagnant until the late 1980s. Much of the focus of research since that time has been on understanding the mechanisms by which lithium compounds control or reduce ASR [136][137][138][139][140][141][142][143][144][145]. A thorough summary can be found in several review documents [146][147][148].…”

Section: Lithiummentioning

confidence: 99%

“…Work by Feng and co-workers [145] focused on Vycor glass disks and glass disks sandwiching a cement paste and exposed to solutions of NaOH, NaOH plus calcium, and NaOH plus calcium and lithium. Their findings showed that in the presence of lithium and calcium, a layer of Li-Si crystals was formed on the surface of the glass disk that helped to protect the silica from further dissolution.…”

Section: Lithiummentioning

confidence: 99%

See 1 more Smart Citation

Alkali–silica reaction: Current understanding of the reaction mechanisms and the knowledge gaps

Rajabipour

Giannini

Dunant

et al. 2015

Cement and Concrete Research

439

197

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Section: Lithiummentioning

confidence: 99%

Section: Lithiummentioning

confidence: 99%

Alkali–silica reaction: Current understanding of the reaction mechanisms and the knowledge gaps

Rajabipour

Giannini

Dunant

et al. 2015

Cement and Concrete Research

439

197

View full text Add to dashboard Cite

“…It is believed that lithium ions protect the reactive silica grain against reaction with sodium and potassium hydroxides, forming a protective layer on its surface. This layer consists of nonexpansive lithium silicates or less expansive silicates with a low sodium and potassium contents enriched with lithium ions [21,22].…”

Section: Methods Of Limiting Asr Inducing Factorsmentioning

confidence: 99%

The use of lithium compounds for inhibiting alkali-aggregate reaction effects in pavement structures

Zapała-Sławeta

Owsiak

2018

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. Internal corrosion of concrete caused by the reaction of reactive aggregate with sodium and potassium hydroxides from cement is a threat to the durability of concrete pavements. Traditional methods for reducing the negative effects of the reaction include the use of unreactive aggregates, low alkali cements, mineral additives or chemical admixtures, incorporated during mixing. Lowering the relative humidity of the concrete below 80% is another measure for limiting the destructive reaction. The incorporation of lithium compounds, in particular lithium nitrate and lithium hydroxide, to the concrete mix is a method of limiting alkali-silica reaction effects. The challenge is to reduce the negative effects of aggregate reactivity in members in which the reaction has occurred because the aggregate happened to be reactive. The paper presents ways of limiting the deterioration of ASR-affected concrete in road pavements and other forms of transportation infrastructure, mainly through the use of lithium compounds, i.e. lithium nitrate. Impregnation methods that allow the penetration of lithium ions into the concrete structure were characterized, as was the effectiveness of the solutions applied.

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“…These include, but are not limited to, a hypothesis of reduced silica reactivity caused by the formation of a layer of lithium silicate crystallites or lithium ion-rich amorphous products on the silica surface. This layer on the surface of the aggregate prevents the reaction of silica with sodium and potassium hydroxides [12,13]. Recent years have brought more reports on the modified composition and properties of sodium-potassium-calcium silicate gels with lithium ions.…”

Section: Effect Of Lithium Nitrate On the Reaction Between Opal Aggrementioning

confidence: 99%

Effect of lithium nitrate on the reaction between opal aggregate and sodium and potassium hydroxides in concrete over a long period of time

Zapała-Sławeta

Owsiak

2017

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. Alkali-silica reaction (ASR) is a reaction between amorphous or poorly crystallized siliceous phase, present in aggregates, and sodium and potassium hydroxides in the pore solution of concrete. Chemical admixtures such as lithium compounds are known to have high potential of inhibiting ASR. The aim of this study was to determine the effect of lithium nitrate on ASR in mortars containing high reactive opal aggregate over a long period of time. Mortar bar expansion tests were performed and microstructures of mortar bars were observed by scanning electron microscopy coupled with an energy dispersive X-ray microanalyser. Results from this study showed that effectiveness of lithium nitrate in mitigating ASR was limited over a long period of time. A larger amount of ASR gel which was formed in the presence of lithium nitrate indicated that the deterioration processes intensify within longer periods of time, which so far has not been observed in literature. Microscopic observation confirmed the presence of alkali-silica gel and delayed ettringite in mortars with lithium nitrate.Key words: alkali-silica reaction, lithium nitrate, ettringite formation, expansion, SEM/EDS. Effect of lithium nitrate on the reaction between opal aggregateand sodium and potassium hydroxides in concrete over a long period of time J. ZAPAŁA-SŁAWETA * and Z. OWSIAK Kielce University of Technology eses have been put forward to explain the role of lithium ions in the reaction. These include, but are not limited to, a hypothesis of reduced silica reactivity caused by the formation of a layer of lithium silicate crystallites or lithium ion-rich amorphous products on the silica surface. This layer on the surface of the aggregate prevents the reaction of silica with sodium and potassium hydroxides [12,13]. Recent years have brought more reports on the modified composition and properties of sodium-potassium-calcium silicate gels with lithium ions. Sodium and potassium ions in gels are exchanged for lithium ions, which makes them less swellable [14,15]. Gels with lithium ions are more compact, which limits the diffusion of hydroxyl, sodium and potassium ions into reactive grains [16]. Studies of the alkali-aggregate reaction have often indicated the presence of delayed ettringite [17,18]. The coexistence of aggregate reaction products with ettringite has been widely observed, especially in concrete railway sleepers in Finland, Sweden, Australia, Germany, South Africa, United States and China [19][20][21][22][23]. According to the current state of knowledge, the delayed ettringite crystallizes in the microcracks generated by the aggregate reaction with sodium and potassium hydroxides, but is not the primary source of the cracks [24,25]. Ettringite is not produced in strongly alkaline environments. However, when the concentration of sodium and potassium hydroxides decreases as a result of reacting with reactive aggregates, the conditions for its crystallization become favourable [26,27].Data on the simultaneous effects of lithium ions on alkali...

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New observations on the mechanism of lithium nitrate against alkali silica reaction (ASR)

Cited by 59 publications

References 7 publications

Alkali–silica reaction: Current understanding of the reaction mechanisms and the knowledge gaps

Alkali–silica reaction: Current understanding of the reaction mechanisms and the knowledge gaps

The use of lithium compounds for inhibiting alkali-aggregate reaction effects in pavement structures

Effect of lithium nitrate on the reaction between opal aggregate and sodium and potassium hydroxides in concrete over a long period of time

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