Influence of Silica Fume on High-Calcium Fly Ash Expansion during Hydration

Barabanshchikov, Yuri; Usanova, Kseniia

doi:10.3390/ma15103544

Cited by 7 publications

(3 citation statements)

References 44 publications

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“…The calculation was reduced to an isothermal hardening regime at a temperature of 20 ºС. The test specimens were cylindrical with a volume of 0.5 L and were prepared in an aluminum cup weighing about 15 g. The course of the experiment and the calculation procedure were taken as in [22].…”

Section: Testing Of Concrete With Cold-bonded Fly Ash Aggregatementioning

confidence: 99%

Properties of concrete containing high-calcium fly ash artificial aggregate

Barabanshchikov,

Usanova,

Umarov

et al. 2023

E3S Web of Conf.

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The work aims to develop a concrete mixture with cold-bonded fly ash aggregate based on high-calcium fly ash and experimentally study its physical and mechanical properties. The results of experimental studies of concrete with artificial coarse aggregate based on fly ash from Berezovskaya Thermal Power Plant showed compressive strength of 28.92 MPa, flexural strength of 4 MPa, coefficient of linear thermal expansion of 14.5 * 10−6 K−1, modulus of elasticity of 16 *109 Pa, heat of hydration on the 10th day - 340 kJ/kg, shrinkage deformation of −1.8 mm/m. It has been established that heat treatment of fly ash aggregate for 8 hours at a temperature of 80 °C after 7 days of air storage did not positively affect the physical and mechanical properties of concrete. The compressive strength at the age of 28 days and the modulus of elasticity of the specimens with coarse aggregate after heat treatment were lower by 41% than that of the control mixture.

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Section: Testing Of Concrete With Cold-bonded Fly Ash Aggregatementioning

confidence: 99%

Properties of concrete containing high-calcium fly ash artificial aggregate

Barabanshchikov,

Usanova,

Umarov

et al. 2023

E3S Web of Conf.

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show abstract

“…The most widespread used SCMs have been fuel ash [ 12 , 13 , 14 ] and ground granulated blast furnace slag [ 15 , 16 , 17 ]. Metakaolin [ 18 , 19 , 20 ] was also applied to reduce the amount of cement produced and thus bring environmental and economic benefits.…”

Section: Introductionmentioning

confidence: 99%

Diatomaceous Earth—Lightweight Pozzolanic Admixtures for Repair Mortars—Complex Chemical and Physical Assessment

et al. 2022

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The presented research is focused on the complex assessment of three different types of diatomaceous earth and evaluation of their ability for application as pozzolana active admixtures applicable in the concrete industry and the production of repair mortars applicable for historical masonry. The comprehensive experimental campaign comprised chemical, mineralogical, microstructural, and physical testing of raw materials, followed by the analyses and characterization of pozzolanic activity, rheology and heat evolution of fresh blended pastes, and testing of macrostructural and mechanical parameters of the hardened 28-days and 90-days samples. The obtained results gave evidence of the different behavior of researched diatomaceous earth when mixed with water and Portland cement. The differences in heat evolution, initial and final setting time, porosity, density, and mechanical parameters were identified based on chemical and phase composition, particle size, specific surface, and morphology of diatomaceous particles. Nevertheless, the researched mineral admixtures yielded a high strength activity index (92.9% to 113.6%), evinced their pozzolanic activity. Three fundamental factors were identified that affect diatomaceous earth’s contribution to the mechanical strength of cement blends. These are the filler effect, the pertinent acceleration of OPC hydration, and the pozzolanic reaction of diatomite with Portland cement hydrates. The optimum replacement level of ordinary Portland cement by diatomaceous earth to give maximum long-term strength enhancement is about 10 wt.%., but it might be further enhanced based on the properties of pozzolan.

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“…The waste that is generated from power plants that use oil as a source of fuel contains generally a high percentage of carbon, alkaline-earth metals, and metals like Co, Fe, and Mn [1]. V, Pb, Ni, Cd, and Cr are also present in this fly ash, and for this reason it is classed as toxic waste [2][3][4][5]. Numerous methods for fly ash processing exist in order to reduce the volume and impact of the waste [6].…”

Section: Introductionmentioning

confidence: 99%

Toxic Elements Behavior during Plasma Treatment for Waste Collected from Power Plants

et al. 2022

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The subject of this work is the treatment of solid waste collected from power plants using thermal plasma technology. Inductively coupled plasma (ICP), X-ray fluorescence (XRF), and energy-dispersive X-ray spectroscopy (EDX) were used to characterize the waste before and after the treatment. The results show that waste is formed essentially from carbon, but it also contains sulfur and toxic elements like lead, cadmium, zinc, and arsenic. For this reason, a plasma reactor was used to separate carbon from the heavy metals by a pyrolysis/combustion plasma system. After the plasma treatment, the mass of the waste was reduced by more than 85% and the metals were collected in the filter bag. A computer code was used to study the toxic element volatility during the treatment. With this code, the effects of plasma temperature, confinement matrix, and the composition of the carrier gas on the volatility of lead and arsenic were determined. The code results show that arsenic remains in the liquid phase for temperatures less than 2000 K, whereas for temperatures beyond 2100 K, arsenic becomes very volatile. For lead, any increase in temperature increases its vaporized quantity and its vaporization speed. The addition of oxygen in the carrier gas leads to the heavy metal incorporation in the confinement matrix. The increase of the quantity of Ba in the containment matrix strengthens the confinement of as in the matrix.

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Influence of Silica Fume on High-Calcium Fly Ash Expansion during Hydration

Cited by 7 publications

References 44 publications

Properties of concrete containing high-calcium fly ash artificial aggregate

Properties of concrete containing high-calcium fly ash artificial aggregate

Diatomaceous Earth—Lightweight Pozzolanic Admixtures for Repair Mortars—Complex Chemical and Physical Assessment

Toxic Elements Behavior during Plasma Treatment for Waste Collected from Power Plants

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