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

Zapała-Sławeta, Justyna; Owsiak, Z.

doi:10.1088/1757-899x/356/1/012008

Cited by 3 publications

(3 citation statements)

References 10 publications

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“…Water is very important for the following processes in the alkali-aggregate reaction: (1) Depolymerization and dissolution of silica; (2) Alkali transport in concrete; (3) Swelling of alkali-silica gel. The current consensus among researchers [10][11][12] is that the swelling of the gel poses a threat to the integrity of the concrete when the humidity is at a high level only. According to Larive [13], the axial expansion of concrete specimens exceeds 1% only when the relative humidity exceeds 80%.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, super-hydrophobic materials (silane impregnating agent) and organic waterproof coating-PVA are selected for modification. Surface protection systems cannot prevent the infiltration of water caused by the cracking of the concrete [11,24], but modified aggregate can isolate alkaline active ingredients from the water completely. And, as an important component of concrete, the aggregate affects the properties of the interface and the ITZ [25][26][27], thereby affecting the mechanical properties of the concrete too [28].…”

Section: Introductionmentioning

confidence: 99%

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Exploration of Waterproofness of Concrete and Alkali-Aggregate Using Hydrophobic Impregnation and Coating

Kang¹,

Yuan²,

Liu³

et al. 2022

Journal of Renewable Materials

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Part of the tunnel spoil can not be used for concrete due to alkali-aggregate reaction (AAR). Water is an indispensable condition for AAR, so separating the alkali-aggregate from water is of great benefit to controlling the AAR. This paper investigates the modification of concrete and aggregate by hydrophobic impregnation and organic coating and then evaluates their waterproof and mechanical properties by dynamic contact angle (DCA), ultrasonic wave velocity, scanning electron microscope (SEM), nuclear magnetic resonance (NMR), and so on. For waterproofness, hydrophobic impregnation and organic coating can both improve the waterproofness of concrete and aggregate. The organic coating is suitable for aggregate because it wrap aggregate well. And aggregate coated by PVA can improve the interfacial transition zone (ITZ). For mechanical properties, both materials will weaken the strength of the interface. Furthermore, concrete made by aggregate with organic coating shows plastic deformation and has a good correlation with the film thickness, a plastic estimation model based on film thickness is proposed. This paper evaluates the waterproof of concrete and aggregate and finds plastic concrete with good aggregate waterproofness which provides a new idea for the application of alkali-aggregate in seepage control facilities of water conservancy projects.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Exploration of Waterproofness of Concrete and Alkali-Aggregate Using Hydrophobic Impregnation and Coating

Kang¹,

Yuan²,

Liu³

et al. 2022

Journal of Renewable Materials

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“…Factors that promote alkali-aggregate reactions needs to be controlled to keep the pavement away from the ASR menace. If any of these factors are partially or completely removed, ASR will be reduced or will not take place [3]. Hence the use of non-reactive aggregates, low alkali cement and pozzolanas can help in this regard.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Analysis of Concrete Using Cow Bone Ash for Alkali-Silica Reaction (ASR) Suppression

Ariyo

Falade²,

Olutaiwo³

2020

JCME

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Concrete pavements are prone to microstructural changes and deterioration when exposed to Alkali-Silica Reaction (ASR). ASR results in strength reduction, cracking, spalling and other defects in the concrete if left unchecked. Supplementary Cementitious Materials (SCMs) such as Cow Bone Ash (CBA) however can be used to improve concrete performance, hence its use in this study. Concrete samples were prepared at replacement levels of 0%, 5%, 10%, 15%, 20% and 30% of cement with Cow Bone Ash. The concrete samples were then subjected to petrographic and Scanning Electron Microscopy (SEM) analysis. Petrographic examination shows that the minimal and least amount of ASR gels and micro cracking were observed at 15% CBA replacement of cement in the concrete samples. Scanning Electron Microscopy (SEM) analysis shows that changes in the elemental composition of the concrete samples is related to the effect of CBA which enhances adhesion in the concrete. SEM analysis show that, in general, the change in microstructure in the concrete was mainly due to the change in the arrangement of the C-H-S compounds. The microstructure analysis indicates that CBA in concrete influences the densification of the concrete at the transition zone, resulting in a much lower porosity. This results in the concrete having a tightly bound layer that repels ingress of water and thereby inhibiting cracks and gel formation as water is a contributing factor to the ASR in concrete.

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Role of Aluminum and Lithium in Mitigating Alkali-Silica Reaction—A Review

Shi

Lothenbach

2022

Front. Mater.

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Effective mitigation of alkali-silica reaction (ASR) is critical for producing durable concrete. The use of alumina-rich supplementary cementitious materials (SCMs) and chemical admixtures such as lithium salts to prevent expansion caused by ASR was first reported 70 years ago, shortly after the discovery of ASR in 1940s. Despite numerous investigations, the understanding of the mechanisms of Al and Li for mitigating ASR remain partially inexplicit in the case of Al, and hardly understood in the case of Li. This paper reviews the available information on the effect of Al and Li on ASR expansion, the influencing factors, possible mechanisms and limitations. The role of Al in mitigating ASR is likely related to the reduction of dissolution rate of reactive silica. Moreover, the presence of Al may alter the structure of crystalline ASR products to zeolite or its precursor, but such effect seems to be not that significant at ambient conditions due to the slow kinetics of zeolite formation. Several mechanisms for the lithium salts in mitigating ASR have been proposed, but most of them are not conclusive primarily due to the lack of knowledge about the formed reaction products. Combination of Al-rich SCMs and lithium salts may be used as an economic solution for ASR mitigation, although systematic studies are necessary prior to the applications.

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

Cited by 3 publications

References 10 publications

Exploration of Waterproofness of Concrete and Alkali-Aggregate Using Hydrophobic Impregnation and Coating

Exploration of Waterproofness of Concrete and Alkali-Aggregate Using Hydrophobic Impregnation and Coating

Microstructural Analysis of Concrete Using Cow Bone Ash for Alkali-Silica Reaction (ASR) Suppression

Role of Aluminum and Lithium in Mitigating Alkali-Silica Reaction—A Review

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