Role of barium carbonate and barium silicate nanoparticles …
Portland cement (PC) is regarded as one of the most common and commercially available binders that are widely used in the construction sector [1].The performance of PC mainly depends on its chemical and/or phase composition (C 3 S, C 2 S, C 3 A, and C 4 AF) as well as its fineness [[1], [2], [3], [4]].Calcium, silicon, ferric, and aluminium oxides are the main …
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Role of Gypsum in Cement and its Effects – …
Gypsum is a mineral and is hydrated calcium sulphate in chemical form. Gypsum plays a very important role in controlling the rate of hardening of the cement, so its is generally termed as retarding agent of cement. It is mainly used ...
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Effect of calcium sulfate source on the hydration of calcium
Calcium sulfoaluminate clinker, industrially produced in China, and commercial micron natural gypsum (C S ‾ H 2) both marketed by BELITH S.P.R.L. (Belgium) were used as raw materials.Bassanite (C S ‾ H 0.5) and anhydrite (C S ‾) were prepared by heating the as-received gypsum at 90 °C for 48 h and at 700 °C for 1 h, respectively. Calcium sulfoaluminate …
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New perspective to improve the sulfate attack resistance of …
Therefore, the pores in concrete may play an important role when the concrete is suffered from sulfate attack. Coral reef debris is a kind of porous and rough natural calcareous material in the island. ... This calcium sulfate may interact with hydrated calcium aluminates to form ettringite again [40].
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Effect of calcium sulfate type and dosage on the properties …
Abstract High-belite sulfoaluminate cement (HBSC), with low carbon dioxide emissions, can be used to repair old concrete. Calcium sulfate plays a significant role in hydration of ye'elimite, but a comprehensive study of the effects of the four different types and dosages of calcium sulfate on the hydration of HBSC is lacking. This study investigates the influence of …
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Hydration mechanism of anhydrite and calcium …
Utilization of Portland cement to initiate the dissolution of blast furnace slag (BFS) in super-sulfated cement is limited by low slag substitution level and poor early strength. In this study, a new activator composed of anhydrite and calcium sulfoaluminate cement clinker was proposed to enhance the utilization of BFS in super-sulfated cement.
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Insight into the role of early C3A hydration in structural …
Early cement hydration processes are predominantly dictated by silicate and aluminate reactions [8].The silicate reaction often involves the dissolution of alite (C 3 S) and the precipitation of portlandite (CH) and calcium silicate hydrate (C-S-H) [9, 10].The aluminate reaction encompasses the dissolution of tricalcium aluminate (C 3 A) and calcium sulfate …
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The role of calcium carbonate in cement hydration
The original cement contains a partially decomposed dihydrated calcium sulfate, which is regenerated after 1 h of hydration and is consumed in about 16 h of setting. ... 558 The role of calcium carbonate in cement hydration T. Matschei a,⁎, B. Lothenbach b, F.P. Glasser a a b Department of Chemistry, University of Aberdeen, Meston Building ...
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Hydration mechanisms of supersulfated cement
Fig. 3 Compressive strength of SSC made with 10, 15 and 20% calcium sulfate (CS) and 0.2, 0.5, and 0.8% KOH: effect of alkaline activator for each CS content Hydration mechanisms of supersulfated cement: the role of alkali activator and calcium sulfate… 973 123
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The role of sulfate ions in tricalcium aluminate hydration: …
Calcium sulfate is used in Portland cement to control the C 3 A reaction to induce the optimum hydration of C 3 S to occur. The amount of calcium sulfate in the Portland cement influences the hydration, rheology, setting, phase assemblage, porosity distribution, and strength in cementitious materials.
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Biodegradable Cements for Bone Regeneration
It is reported that calcium sulfate cement generally takes 4–6 weeks to completely degrade under the condition of good blood vessels. However, the degradation time of calcium sulfate was prolonged to 6–10 …
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STUDIES OF THE ROLE OF CALCIUM SULPHATE IN THE …
SULPHATE IN PORTLAND CEMENT CLINKER MAY ORIGINATE FROM THE CLAY OR CALCIUM SULPHATE OF THE RAW MIX, FROM THE FUEL, OR FROM THE USE OF MINERALIZERS. ITS RETENTION IN THE CLINKER IS INFLUENCED BY THE KILN ATMOSPHERE. STUDIES ARE IN PROGRESS OF THE ROLE OF SULPHATE IN THE …
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Understanding the role of calcium formate towards …
Besides, the resistance to sulfate attack would be decreased by the large amount of inorganic salt accelerators [2]. Calcium formate (CF), considered as an environmental friendly cement accelerator, has been widely used in construction [23].
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Influence of Content and Source of Calcium Sulfate on …
Supersulfated cement (SSC) consists essentially of blast-furnace slag and calcium sulfate. It can be considered an alternative to Portland cement because its production minimizes the environmental impacts caused by the exploration of raw materials and CO 2 emissions. However, the long-term durability of SSC still needs to be studied.
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Impact of C3A Polymorphism, Lignosulfonate Admixture, …
The effect of C 3 A polymorphism, the calcium sulfate source, and the addition of limestone on the hydration kinetics and rheology of cement pastes and their interaction with a lignosulfonate-based admixture were analyzed. Two clinkers produced in industrial cement rotary kilns using the same raw materials and process were produced; their crystallinity was changed …
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(PDF) Influence of calcium sulphate on hydration and …
Calcium sulfate, like gypsum, hemihydrate, and/or anhydrite, is added in Portland cement (PC) to control the C 3 A hydration and subsequently improve its industrial application feasibility [1,2].
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Influence of alkali sulfates in clinker on the hydration and …
Sulfate, a minor but important component, in Portland cement plays a significant role in cement concrete. The reaction of sulfate in cement with calcium aluminate affects the setting time, fluidity, compressive strength, volume stability and durability [1], [2].Adequate sulfate in cement would be beneficial to the setting time, development of compressive strength and …
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Mechanisms of cement hydration
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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Sodium Sulphate
3. Improving the strength of cement: Calcium sulfate generated by the reaction of sodium sulfate and calcium hydroxide is a hard substance that can increase the strength of cement. At the same time, sodium sulfate can also promote the formation of calcium aluminate in cement, further improving the strength of cement. The role of sodium sulfate ...
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Exploring the Uses of Calcium Sulfate in Everyday Life
Calcium sulfate (CaSO₄) is a remarkable chemical compound that plays a significant role in various industries and daily life. This naturally occurring mineral exists in different forms depending on its hydration level, including anhydrous calcium sulfate, hemihydrate (CaSO₄·0.5H₂O), and dihydrate (CaSO₄·2H₂O).
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Effects of sulfates on the hydration of Portland cement -A …
a b s t r a c t Presented within is a critical overview of the effect of sulfates on cement hydration, properties, and optimum sulfate content in Portland cement. Calcium sulfate is used in ...
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Application of Calcium Sulfate Whiskers to Cement-Based …
In recent years, significant attention has been paid to the use of calcium sulfate whiskers (CSWs) to enhance the performance of cement-based materials (CBM). This technology has attracted widespread interest from researchers because it enhances the performance and sustainability of CBM by modifying the crystal structure of calcium sulfate.
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Influence of free calcium sulfate levels on the early …
Distinct from conventional CSA cement, sulfate-rich BSA clinkers containing f-CaSO 4 present unique crystal structures and hydration activities [21]. Consequently, understanding the influence of C$ addition on cement hydration is crucial. ... Exploring the role of calcium sulfate in supersulfated cement: A study of rheological, mechanical, and ...
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The role of sulfate ions in tricalcium aluminate hydration: New
a b s t r a c t Presented within is a critical overview of the effect of sulfates on cement hydration, properties, and optimum sulfate content in Portland cement. Calcium sulfate is used in ...
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Early-age hydration of ye'elimite (calcium sulfoaluminate …
Calcium sulfoaluminate-belite (CSAB) cement is considered a viable and environmentally friendly alternative to Portland cement. Ye'elimite or calcium sulfoaluminate which is the primary phase of CSAB cement undergoes rapid hydration, leading to the formation of ettringite or monosulfate as the major hydration product. The reactivity of ye'elimite can be …
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Influence of calcium hydroxide and calcium sulfate on early …
A commercially available CSAB cement, laboratory-grade calcium sulfate dihydrate (gypsum) and calcium hydroxide were used in this study. The oxide and phase compositions of CSAB cement as determined from X-ray fluorescence (XRF) and quantitative X-ray diffraction (QXRD) are given in Table 1.The binder predominantly contained ye'elimite with an M-value of …
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The role of sulfate ions in tricalcium aluminate hydration: New
DOI: 10.1016/j.cemconres.2020.105973 Corpus ID: 212767437; The role of sulfate ions in tricalcium aluminate hydration: New insights @article{Liu2020TheRO, title={The role of sulfate ions in tricalcium aluminate hydration: New insights}, author={Xin Liu and Pan Feng and Chengjian Lyu and Shaoxiong Ye}, journal={Cement and Concrete Research}, year={2020}, …
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The Role of Calcium Carbonate in Cement Hydration
The Role of Calcium Carbonate in Cement Hydration. April 2007; ... especially in high Al2O3 slag blended concrete. Sulfate optimization was performed on a total of 26 blended mixtures of 5 ...
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The purpose of calcium sulfate (gypsum)
What is the purpose of calcium sulfate (gypsum)? A. For modern cements, the rate of stiffening of the cement paste should be controlled within limits to make the cement a useful product. If the …
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Influences of the type and amount of calcium sulphate …
The role of calcium sulphate as a setting -time regulator is widely known in the modern cement ... cement's performance under this particular poi nt of view, is still a fertile terrain for open discussions. ... gypsum to other calcium sulfate forms . The compositions are reported in the table 1, along with the
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