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Ettringite

About: Ettringite is a research topic. Over the lifetime, 2702 publications have been published within this topic receiving 67056 citations. The topic is also known as: woodfordite.


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Journal ArticleDOI
TL;DR: In this paper, the authors assess the effect of several chemical compounds (called precursors) in particular calcium gluconate, calcium lactate and urea, that could enhance the intensity of self-healing and serve as nutrients at later ages for either autogenous bacteria or bacteria subsequently added by spraying the concrete surface with a bacterial suspension.

26 citations

Journal ArticleDOI
TL;DR: In this article, the results of a study on sulfate resistance of early opening-to-traffic concretes with accelerating admixture, also known as fast-track concrete (FTC), are presented.
Abstract: The results of a study on sulfate resistance of early opening-to-traffic concretes with accelerating admixture, also known as fast-track concretes (FTC), are presented. A total of 11 concretes made with four different cement factors and three different cement types were investigated at both opening and maturity (28 days) ages. Upon curing, the test samples were immersed in a 5% sodium sulfate solution. Length change, mass loss, and compressive strength were monitored for a period of 270 days to evaluate the performance of the test specimens exposed to severe sulfate attack. The influence of immersion period, curing age and cement type and factor on bulk characteristics and sulfate resistance were evaluated. The study produced FTC with excellent sulfate resistance. Length change of FTC incorporating accelerating admixture increased with increasing immersion age and stabilized within 3 months from initial contact. No mass of concrete residues nor notable strength loss were found in any opening time fast track concretes used in the investigation.

26 citations

Journal ArticleDOI
Xiaolei Lu1, Zhengmao Ye1, Lina Zhang1, Pengkun Hou1, Xin Cheng1 
TL;DR: In this paper, the effect of ethanol-diisopropanolamine (EDIPA) on the hydration and mechanical properties of Portland cement was focused on in this study.

26 citations

Journal ArticleDOI
Chen Li1, Mengxue Wu1, Wu Yao1
TL;DR: In this article, a ternary cementitious system consisting of belite-ye-elimite-ferrite (BYF) cement, limestone filler, and silica fume was proposed.
Abstract: One of the main concerns in the modern cement industry is on reducing the CO2 emissions. As an alternative binder of Portland cement, belite-ye’elimite-ferrite (BYF) cement can reduce the CO2 emission by over 20% due to its benefits concerning the chemical composition and industrial processing. This paper proposed a ternary cementitious system consisting of BYF cement, limestone filler, and silica fume. The ternary system containing 10% limestone and 5% silica fume showed higher compressive strength than the BYF cement, while the CO2 emission factor further reduced by ∼13%. The effect of limestone and silica fume on the hydration was studied. It was found that the hydration reaction of limestone induced the formation of hemicarbonate and stabilized ettringite. This reaction formed dissolution rims around the limestone particles. At the early hydration ages, silica fume was bonded by aluminum hydroxide, forming aluminate silicate hydrate. During the hydration, the silicate dissolved and reacted with the hy...

26 citations

DOI
01 Jan 2014
TL;DR: In this paper, the authors studied the properties of CACs with and without supplementary cementitious materials (SCM) from the first hours up to two years of hydration and showed that the calcium sulfate reacts with CAC and only when sulfate is exhausted does slag or limestone react with aluminate phases.
Abstract: Calcium aluminate cements (CAC) are often used in combination with calcium sulfate and Portland cement for special applications where rapid setting, rapid drying and shrinkage compensation are required. A growing fraction of the clinker, which has the highest CO2 intensity, is being replaced by supplementary cementitious materials (SCM). These SCM are usually from industrial by-products such as slag, fly ashes or can simply be raw materials such as limestone. This project aims at replacing the Portland cement and fraction of the CAC in ternary binders with such SCM. Indeed, the understanding of their interactions, both physical and chemical, with calcium aluminate cements and calcium sulfate is fundamental for the development of innovative products. This thesis focuses first on the hydration of systems with and without SCM, slag or limestone, from the first hours up to two years of hydration. Second, this study focuses on the expansion of these systems and on the mechanisms underlying the dimensional stability. The influence of the ratio between calcium sulfate and calcium aluminate on the hydration of the cement, on the reaction of SCM, and on the expansion is highlighted. This study indicated that the calcium sulfate reacts with CAC from the first hours of hydration and, only when sulfate is exhausted, does slag or limestone react with aluminate phases. Moreover, this research brings new insights on the main parameters influencing the dimensional stability of the studied systems and on the mechanisms governing expansion. Pore solution analyses showed that supersaturation with respect to ettringite increases with the calcium sulfate content, which results in an increase of the crystallization pressure. The supersaturation determines the minimum pore size in which crystals can grow. Therefore, with increasing supersaturation a larger pore volume can be accessed by ettringite crystals exerting pressure. This could explain the critical amount of calcium sulfate leading to high expansion. Both the confinement in nanometer size pores and the supersaturation of ettringite are necessary for expansion to occur.

26 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023244
2022439
2021175
2020161
2019166
2018143