Efficiency of Fly Ash in Mitigating Alkali-Silica Reaction Based on Chemical Composition

Malvar, L. J.; Lenke, Lary R

doi:10.14359/18153

Cited by 19 publications

(5 citation statements)

References 12 publications

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“…In previous papers (Donatello et al, 2013) authors have already demonstrated that hybrid cements behave quite well when located in aggressive environmental conditions (sulfates, marine, acidic, etc.). Additionally, they do not undergo the ASR since alkalies are consumed in the reaction of activation of fly ashes (Malvar and Lenke, 2006).…”

Section: Materials Propertiesmentioning

confidence: 99%

Studies About the Hydration of Hybrid “Alkaline-Belite” Cement

2019

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The mechanical performance of a hybrid cement containing 48% fly ash, 48% mineralized belite clinker, 1. 5% gypsum and 2.5% Na 2 SO 4 was analyzed and the hydration products were identified. The findings showed that the newly designed cement met European standard EN 197-1 compositional, mechanical and setting time requirements (cement type IVB). The hydration products forming in this blended "alkaline-belite" cement (as it was determined through XRD, 29 Si and 27 Al MAS NMR and electron microscopy) consisted in a mix of cementitious gels: C-(A)-S-H and N-(C)-AS -H, which interacted and over time evolved toward the latter with no detriment to the mechanical strength developed by the cement.

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Section: Materials Propertiesmentioning

confidence: 99%

Studies About the Hydration of Hybrid “Alkaline-Belite” Cement

2019

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“…Since the initial discovery of ASR back in 1940s, it has been widely studied around the world. Most of the studies focused on the following aspects that include: a) investigations and treatments of ASR-affected structures [2,3,4] b) establishment of correlations between laboratory results and eld performance [5,6,7] c) laboratoryaccelerated methods of inducing ASR in concrete [8,9] d) evaluation procedures and inhibition measures of ASR [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24] e) effects of ASR on the properties of concrete [25,26,27,28] 3.1 Evaluation Methods of ASR Field performance history is the best method of evaluating the susceptibility of an aggregate to ASR. When eld history is not available, the potential reactivity of an aggregate can only be ascertained through laboratory testing.…”

Section: Literature Reviewmentioning

confidence: 99%

“…With an average result of 22, the Flakiness Index of SR aggregates has been classi ed as FI 35 . In comparison, granite aggregates were relatively more angular in shape as it registered a Flakiness Index of 9 and has been characterised as FI 15 . Notwithstanding the high Flakiness Index, the aggregate crushing value, ten per cent nes value, aggregate impact value and Los Angeles abrasion coe cient demonstrated that SR aggregates were sturdier than granite aggregates and met the requirements of coarse aggregates for concrete production.…”

Section: Properties Of Sr Aggregatesmentioning

confidence: 99%

Performance of Structural Concrete Containing Sedimentary Rocks

Lim,

Lee,

et al. 2024

Preprint

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In 2014, Singapore commissioned the Jurong Rock Caverns (JRC) for the storage of liquid hydrocarbons. The construction of this first commercial underground storage facility in Southeast Asia had extracted about four million cubic metres of rocks which comprised mainly sedimentary rocks (SR). To offset the development costs of JRC and reduce the reliance on imported natural aggregates, studies were conducted to evaluate its applications in construction. One of the studies has shown that it could be processed into aggregates for road construction. However, SR aggregates found to be susceptible to the alkali-silica reaction (ASR) which posed a concern for concrete production. A preliminary study was carried out to find a way to mitigate this phenomenon and the introduction of ground granulated blast-furnace slag (GGBS) yielded the best outcome. Further study was undertaken to investigate various concrete mixes that contained 100% SR aggregates and different replacement levels of ordinary Portland cement (OPC) with GGBS. The structural performance of these mixes was assessed through a series of mechanical tests. The test results demonstrated that GGBS was effective in suppressing the ASR-induced expansions while meeting the specifications of structural concrete. A comparable performance was also observed when the proposed mixes were benchmarked against the conventional concrete made up of granite aggregates and OPC. This study has led to the development of a new and sustainable construction material in Singapore which offers an alternative to the imported aggregates and a circular economy approach to alleviate the pressing issue of landfill.

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“…Changes in the microstructure directly affect the macroscopic mechanical properties and durability of concrete [21]. Fly ash considerably affects the composition and microstructure of concrete hydration products [22]. e volcanic ash reaction densifies the concrete matrix, and the ash reacts with calcium hydroxide during cement hydration to produce additional C-S-H and calcium aluminate hydrate (C-A-H), thereby reducing the concrete porosity and optimizing the internal microinterface.…”

Section: Introductionmentioning

confidence: 99%

“…Studies regarding the microstructure of fly ash concrete indicate that fly ash can refine the internal pore structure. When fly ash was used, the number of large pores decreased [21], the number of fine pores increased, and the total porosity and average pore size decreased significantly, thereby enhancing the resistance of concrete to chloride ion attack [22].…”

Section: Introductionmentioning

confidence: 99%

Durability Performance of Concrete with Fly Ash as Fine Aggregate Eroded by Chloride Salt

Mao

Zhang

et al. 2022

Advances in Materials Science and Engineering

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The aim of this study is to investigate the durability of concrete with fly ash as a fine aggregate (CFA) in chloride salt environments. The natural diffusion method is used to analyze the concrete strength, chloride ion concentration, and diffusion coefficient after chloride salt erosion in a laboratory environment. In addition, scanning electron microscopy, X-ray diffraction, and Mercury intrusion porosimetry are performed to clarify the deterioration mechanism of concrete in chloride salt environments. The results indicate that owing to the chloride ion binding effect, the concrete porosity decreases and the concrete strength increases after chloride salt immersion. The decreased porosity caused by delayed hydration is primarily due to Friedel’s salt and CaCO3 produced during chloride ion erosion. CFA has a lower chloride diffusion coefficient and lower chloride concentration compared with ordinary concrete at all depths. In general, CFA exhibits excellent resistance to chloride salt erosion.

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Efficiency of Fly Ash in Mitigating Alkali-Silica Reaction Based on Chemical Composition

Cited by 19 publications

References 12 publications

Studies About the Hydration of Hybrid “Alkaline-Belite” Cement

Studies About the Hydration of Hybrid “Alkaline-Belite” Cement

Performance of Structural Concrete Containing Sedimentary Rocks

Durability Performance of Concrete with Fly Ash as Fine Aggregate Eroded by Chloride Salt

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