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The RILEM technical committee 282-CCL: Calcined Clays as Supplementary Cementitious Materials, investigates all the aspects related to calcined clays, from clay exploration and characterization to calcination process, hydration reactions and concrete properties. This white paper focuses on the hydration mechanisms of calcined clay-blended Portland cements, …
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The main mineral components of red mud are cancrinite, calcite, dicalcium silicate, tricalcium aluminate, hematite, goethite, boehmite, gibbsite, etc ... material gradually weakened, and this is mainly attributable to the reduction in red mud content. It is well known that cement hydration can generate large amounts of Ca(OH) 2, but ...
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concrete, high-performance heavyweight concrete mixes using the coarse aggregates of magnetite (M), barite (B), goethite (G) and serpentine (S) were designed. Heavyweight concrete mixes can be proportioned using the American Concrete Institute method (ACI) of absolute volumes developed for normal concrete (Bunsell and Renard 2005).
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The results indicated that, the compres- sive strengths of concrete mixes M1, M2 and M3 (containing magnetite aggregate) are significantly higher than those con- taining barite, goethite and ...
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The current state of knowledge of cement hydration mechanisms is reviewed, including the origin of the period of slow reaction in alite and cement, the nature of the acceleration period, the role of calcium sulfate in modifying the reaction rate of tricalcium aluminate, the interactions of silicates and aluminates, and the kinetics of the deceleration period.
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Based on the TGA, XRD and SEM results, it is inferred that the further hydration of unreacted cement particles in the specimens with 0.4 w/c ratio was inhibited, attributed to the reduced contact ...
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It is evident also from Fig. 2 that, the concrete mixes made from the coarse aggregates of goethite and containing 10% SF (G1) and 20% FA (G2) meet the requirements of dense concrete exceeding by about 2% and 1%, respectively; while, the density of concrete was declined by about 2% for the concrete matrix containing 30% GGBFS (G3) as a ...
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Precast concrete, cold weather concreting and the emerging technique of concrete additive manufacturing (AM) are applications in which the acceleration of cement hydration plays a critical role.
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Temperature is one of the most important factors affecting the hydration process and the crystallinity of cement pastes, and its effect on the gel phase cannot be ignored. The Fe(OH)3 phase is an indispensable gel phase in calcium sulfoaluminate cement, which significantly contributes to the desirable properties of CSA cement (especially ferric-rich …
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The selected fine powdered boron carbide was found to be beneficial to the physic-mechanical properties of concrete as it enhances the cement hydration reaction due to the filler effect; thus, the ...
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Goethite is a major constituent in ferruginous soils in a ... firstly carried out leaching experiments considering temperature effects to construct a solubility equilibrium model of cement hydrate.
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Here, we combined wet chemistry methods, synchrotron- based X-ray techniques, and thermodynamic modelling to explore the redox interactions and non-redox sorption processes …
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In the OL system, oleate ions are chemically adsorbed on the surface Fe sites of goethite in the absence of hydration, while in the presence of hydration, the oleate ions were …
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Goethite (α-FeOOH) is a common oxy-hydroxide in natural environment and is formed as a weathering product of iron-bearing minerals. This mineral is the most important …
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The microsilica additive showed an alkaline reaction in the water solution that can more actively react with cement hydration product on the surface of the metal particles. The …
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According to reaction kinetics, goethite and hematite can only precipitate at elevated temperatures, such as 50 °C within months or 80 °C within days [81], ... Accelerated cement hydration during the first 24 h and the retarded hydration after 1 day in the presence of lithium is confirmed. From the NMR results, lithium mainly retards the ...
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The hydration product Fe (OH) 3 gel phase or Al-containing Fe (OH) 3 [abbreviated as (A / F) H 3] gel phase enables calcium sulfoaluminate cement (CSA) to obtain excellent cementitious properties.The formation of these two gels is closely related to the ratio of Al and Fe in the raw materials. The microstructure and properties of hydration products in CSA …
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The paper deals with thermodynamic modeling of Portland cement hydration as a complex system, which describes the clinker dissolution, diffusion, and surface phenomena that occur on phase nuclei ...
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A review of hydro-mechanical coupling behaviour of cement-treated materials. Peng Jing, ... Hossein Nowamooz, in Construction and Building Materials, 2022. 3.1 Hydration process. Cement hydration is a key factor affecting the hydro-mechanical coupling behaviour of cement-treated materials. As a hydraulic cementing medium, during hydration, cement produces gelatinous …
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Rath et al. [31] studied the chemisorption of sodium oleate on the goethite surface based on DFT calculations, while the latest report suggested that sodium oleate could adsorbed on the goethite ...
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The formation conditions, solubility and stability of monohydrocalcite (MHC, CaCO3H2O), as well as sorption behaviors of toxic anions on MHC, are reviewed to evaluate MHC as a remediation material ...
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To investigate the effect of heavyweight aggregate on the physico-mechanical properties of concrete, high-performance heavyweight concrete mixes using the coarse aggregates of magnetite (M), barite (B), goethite (G) and …
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Full Professeur-Exceptional Class 2, Director of LGCgE Laboratory. Director of International Master - Cited by 7,795 - Geo-materials and other materials - Naomaterials - Materials for Civil engineering (concrete-minerals-clays-geopolymers) and envi
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Cement hydration is a complex process, as cements normally consist . ... H instead of goethite as iron . rich phase at lower water cement ratios. In addition, a signi cant .
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Concrete is the most widely used material in civil engineering, accounting for approximately 10–20% of the total volume of materials used in this field 1,2.In 2019, global production of concrete ...
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The effect of polycarboxylate (PC) superplasticizers with different structure on the rheological properties and hydration process of slag-blended cement pastes with a slag content between 0 and 75% has been studied. Fluidizing properties of PCs admixtures are significantly higher in slag-blended cement with respect to non-blended Portland cement. Also, it has been …
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In some mixes, compressive strengths were also tested up to 90 days upon replacing sand with the fine portions of magnetite, barite and goethite. The mixes containing magnetite along with …
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The cement used in this study is a commercial Portland cement (Lafarge North America Corp.) that satisfies Type I and Type II requirements set forth in ASTM American Society for Testing and Materials (ASTM) C-150 [8].The properties of Portland cement are presented in Table 1.Four iron oxides (and oxyhydroxides) were used for this study: magnetite, hematite, …
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Bauxite residue (BR) is a by-product from the aluminum industry, generated during the Bayer process to obtain alumina. It has valuable iron and alumina contents, with soluble ions that can interact with the cement compounds, which could make BR a new source of supplementary cementitious material. This work aims to determine the influence of different …
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Compared with PRS-0, PRS-1, PRS-2, PRS-3, PRS-4, and PRS-5 have obvious characteristic peaks of ettringite and calcium sulfate dihydrate. This is due to the increased …
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Single file - hydration of Portland cement Hydration of a Portland cement The example will show the principle possibility to apply GEMS to simulate cement hydration. A cement composition from literature is used. hydration with w/c = 0.50 at 20°C …
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On the contrary, the concrete mixes made with goethite and serpentine coarse aggregate along with 10% SF, 20% FA and 30% GGBS did not satisfy the requirements of high-performance ... This leads to an increase in the compressive strength of concrete. Also, the hydration products possess a large specific volume than the unhydrated cement ...
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To summarize, cement hydration induces a volume reduction of evolving cement-based materials that is usually called shrinkage. ... Monocarboaluminate, Monosulfoaluminate, Ettringite, Hydrocalcite, Goethite, in addition to the minerals present in the cement (see section 3.1). 3.4. Stress and volume evolution.
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The substitution of cement by clays calcined at 750 • C, and by metakaolin, resulted in a similar reduction of CH content in pastes; up to 60%, relative to neat cement, at all hydration ages.
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In this study, the first-principles density functional theory calculations were used to reveal the role of the hydration of the goethite surface and its effects on flotation reagents from a microscopic perspective. The calculation results showed that DDA was adsorbed on the surface of goethite by hydrogen bonds in the absence of hydration.
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Using PHREEQC to model cement hydration ... A.A. Kamnev, et al., Investigation of the solution process of goethite (alphaFeOOH) in alkaline solutions, Russian J. Appl. Chem. (Zhurnal Prikladnoi Khimii) 59 (1986) 1560–1564. [146] Z. Yishin, A. Ruiyang, Y. Chen, Determination of the solubility of Fe2O3 in dilute aqueous solutions at 300oC and ...
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