scholarly journals Circulation Fluidized Bed Combustion Fly Ash as Partial Replacement of Fine Aggregates in Roller Compacted Concrete

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4204 ◽  
Author(s):  
Wei-Ting Lin ◽  
Kae-Long Lin ◽  
Kailun Chen ◽  
Kinga Korniejenko ◽  
Marek Hebda ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Fluidized Bed ◽  
Setting Time ◽  
Unit Weight ◽  
Fluidized Bed Combustion ◽  
Sulfate Resistance ◽  
Roller Compacted Concrete ◽  
Fine Aggregates

Recently, many people around the world have been concerned with environmental protection and sustainability. The goal of various countries’ research has been focused on how to regenerate existing resources. Circulation fluidized bed combustion (CFBC) technology is one of the emerging combustion technologies for electricity generation and produces more than 800,000 tons of CFBC fly ash (CFA) per year for combustion. CFA has been widely applied in cement additive, new building materials and cement-based materials. The goal of this study was to discuss the engineering properties of roller-compacted concrete containing CFA. Test subjects included compressive strength, flexural strength, absorption, setting time, unit weight, sulfate resistance, SEM microscopic observations and XRD ingredient analysis. Test results indicate the following: (1) using CFA as a substitute of fine aggregates up to 10 wt.% would improve the development of later flexural strength; (2) the increases in pre-pressure would increase the compressive strength and unit weight and decrease absorption; (3) using CFA would reduce the initial setting time by 30%–60% and reduce the final setting time by 16%–20%; (4) using CFA would reduce the absorption; (5) using CFA would reduce the unit weight by 0.5%–2.8%, and the increases in pre-pressure would increase the unit weight by about 0.9%–2.1%; (6) CaO in CFA helps to improve sulfate resistance; (7) scanning electron microscopy (SEM) observation shows that the increases in pre-pressure would reduce the pores; and (8) X-ray diffraction (XRD) analysis shows that the inclusion of CFA would increase the content of Ca(OH)2 in concrete.

Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement

2014 ◽  
Vol 629-630 ◽  
pp. 306-313 ◽  
Author(s):  
Mao Chieh Chi ◽  
Ran Huang ◽  
Te Hsien Wu ◽  
Toun Chun Fou
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Building Materials ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Fluidized Bed Combustion ◽  
Initial Setting Time ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.

scholarly journals Solidification of Municipal Solid Waste Incineration Fly Ash through Co-Mechanical Treatment with Circulation Fluidized Bed Combustion Fly Ash

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 141
Author(s):  
Zhengzhen Yao ◽  
Zhonghui Xu ◽  
Qin Shuai ◽  
Xiaoyue Chen ◽  
Zao Jiang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Fluidized Bed ◽  
Mechanical Treatment ◽  
Waste Incineration ◽  
Municipal Solid Waste Incineration ◽  
Fluidized Bed Combustion ◽  
Waste Incineration Fly Ash

This study aims to explore the solidification performance of municipal solid waste incineration fly ash (MSWIFA) through co-mechanical treatment with circulation fluidized bed combustion fly ash (CFBCFA). The mineral characterization, physical properties, and leaching resistance of the solidified bodies are investigated by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry-differential thermal analysis (TG-DTA), compressive strength, porosity, and leaching test, respectively. C–S–H, ettringite (AFt), and Friedel’s salt (FS) are the predominant hydrate products in the CFBCFA based solidified bodies, which are similar to the cement based solidified bodies. However, CFBCFA based solidified bodies exhibit higher compressive strength (36.7 MPa) than cement based solidified bodies (11.28 MPa), attributing to the three reasons: lower porosity and more compact internal structure of CFBCFA based solidified bodies; large amounts of Ca(OH)2 originating from MSWIFA are conducive to promoting the hydration reaction extent and compressive strength of the CFBCFA based solidified bodies; excessive Ca(OH)2 would cause compressive strength deterioration for the cement based solidified bodies. The heavy metals (Zn, Cu, Cr, Cd, and Pb) concentrations in the extraction solution of the CFBCFA based solidified bodies are far below the requirements of Chinese National Standard GB 5085.3-2007. The solidification of MSWIFA through co-mechanical treatment could be an ideal substitute for cement solidification technology.

scholarly journals Effect of fly ash on physical and mechanical properties of mortar

2019 ◽  
Vol 17 (6) ◽  
pp. 35
Author(s):  
Vu-An Tran
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Water Absorption ◽  
Thermal Power ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Flow Density ◽  
Control Specimen

This research investigates the physical and mechanical properties of mortar incorporating fly ash (FA), which is by-product of Duyen Hai thermal power plant. Six mixtures of mortar are produced with FA at level of 0%, 10%, 20%, 30%, 40%, and 50% (by volume) as cement replacement and at water-to-binder (W/B) of 0.5. The flow, density, compressive strength, flexural strength, and water absorption tests are made under relevant standard in this study. The results have shown that the higher FA content increases the flow of mortar but significantly decreases the density of mixtures. The water absorption and setting time increases as the samples incorporating FA. Compressive strength of specimen with 10% FA is approximately equal to control specimen at the 91-day age. The flexural strength of specimen ranges from 7.97 MPa to 8.94 MPa at the 91-day age with the best result for samples containing 10% and 20% FA.

Study on the Utilization of FBC Ashes as Cement Admixture

2011 ◽  
Vol 99-100 ◽  
pp. 116-119
Author(s):  
Jing Xiang Liu ◽  
Yuan Ming Song ◽  
Hui Zhong Xu ◽  
Yu Long Ma ◽  
Yu Bo Yue ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Fluidized Bed ◽  
Coal Combustion ◽  
Cement Mortar ◽  
Setting Time ◽  
Pulverized Coal Combustion ◽  
Fluidized Bed Combustion ◽  
Fly Ashes ◽  
Cement System

Compared with ordinary Pulverized Coal Combustion (PC) fly ashes, Fluidized Bed Combustion (FBC) ashes have some special properties. The effect of FBC ashes content on the strength of cement mortar was studied, and the physical properties of FBC ashes-cement mortar with 30% FBC ashes were also investigated. The results show that the flexural and compressive strength at 7 and 28 days of the mortar gradually decreases with the increase of FBC ashes content. Under the same dosage, the strength of FBC ashes-cement mortar is greater than that of PC fly ashes-cement mortar. The FBC ashes-cement system presents a normal setting time but poor soundness with more than 3.5% SO3. This work confirms that the properties of FBC ashes-cement system are superior to those of PC fly ashes-cement system when SO3 content is no more than 3.5%.

scholarly journals Influence of the Composition and Curing Time on Mechanical Properties of Fluidized Bed Combustion Fly Ash-Based Geopolymer

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2527
Author(s):  
Natalia Wielgus ◽  
Jan Kubica ◽  
Marcin Górski
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Environmentally Friendly ◽  
Raw Material ◽  
Fluidized Bed Combustion ◽  
Precast Elements ◽  
Ash Disposal ◽  
Fbc Fly Ash

This paper presents novel research on a fluidized bed combustion (FBC) fly ash-based geopolymer as a contribution to the problem of FBC fly ash disposal, and a proposal for a new geopolymer composition—an environmentally friendly material that is possible to use in construction. Geopolymer samples of various composition (containing FBC fly ash as the main raw material, metakaolin and CRT glass as additional components, and sodium silicate and sodium hydroxide as activators) were subjected to flexural and compressive strength tests. An investigation on the effect of the demolding time was carried out on one selected mixture. The test showed that both the composition and the demolding time have a decisive influence on the basic mechanical properties. A mixture containing FBC fly ash to metakaolin in a mass ratio of 3:1, removed from the mold after 14 days, was found to be the best in terms of the mechanical parameters expected from a material that could be used in construction, e.g., for the production of precast elements. According to the results obtained, FBC fly ash is a promising and environmentally friendly raw material for the production of geopolymer, with good mechanical properties and low density. Moreover, a high compressive strength can be obtained by curing the geopolymer at ambient temperature.

Advancements in Properties of Cement Containing Pulverised Fly Ash and Nanomaterials by Blending and Ultrasonication Method (Review - Part I)

2018 ◽  
Vol 19 ◽  
pp. 1-11 ◽  
Author(s):  
Mehmet Serkan Kirgiz
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Water Demand ◽  
Review Paper ◽  
Setting Time ◽  
Heat Of Hydration ◽  
Strength Gain ◽  
Hydration Properties ◽  
Carbon Nano Tube

This review research aims to discuss the results obtained researches on cement containing pure cement, pulverised fly ash, and nanoparticles, in order for eliminating negative side effects underlie the substitution of by–products for pure Portland cement. Nanoparticles (NP) used in these researches are nanoTiO2, nanoSiO2, nanoCaCO3, fibers of carbon nano tube (CNT), nanolimestone (nanoCaCO3), nanoZrO2, nanoclays, and nanometakaolin (nMK) for improving properties of cement systems. Published manuscripts explains two methods regarding on the usage of nanoparticles for cement system: blending and ultrasonication for dispersion of nanoparticles. However, differences between blending and ultrasonication methods suggested by various researchers are also discussed. Experiments reported these papers include the water demand, the density, the setting–times, the heat of hydration, the fluidity, the compressive strength and the flexural strength. According to these results, nanoparticles increase the water demand and heat of hydration of cement; it decreases the density and fluidity for cement mortars, evidently. The most effective nanoparticles on early compressive and flexural strengths are fibers of carbon nano tube and nanoCaCO3. These papers also point effects of these nanoparticles on the strength gain of cement. This review paper inform us until Effect of nanomaterial on water demand and density section in this Part I. Second part of this review paper will explain Hydration properties of Portland pulverised fly ash cement section, Effect of nanomaterial on setting–time section, Effect of nanomaterial on heat of hydration section, Strength gain mechanisms for hardened Portland pulverised fly ash cement paste and mortar section, Effect of nanomaterial on compressive strength section, Effect of nanomaterial on flexural strength (Bending) section, and Conclusion section.

scholarly journals Mechanical Activation of the Ca-Rich Circulating Fluidized Bed Combustion Fly Ash: Development of an Alternative Binder System

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Peeter Paaver ◽  
Päärn Paiste ◽  
Martin Liira ◽  
Kalle Kirsimäe
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Activation ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Chemical Activation ◽  
Fluidized Bed Combustion ◽  
Strength Performance ◽  
Mineral Characteristics ◽  
Circulating Fluidized Bed Combustion

Mechanical activation of the calcium-rich fly ash formed in circulating fluidized bed combustion (CFBC) boilers was investigated to enhance the compressive strength performance of the pastes. We studied the effect of the activation on the physical, chemical, and mineral characteristics of fly ash and its pastes. Our study shows that already a short mechanical activation yields a 10-fold improvement in the compressive strength of the pastes, reaching 60 MPa after 90 days of curing without any chemical activation or blending. Mechanical activation caused fragmentation of large porous aggregates in the raw ash enhancing the physical properties and reactivity of fly ash particles. Similarly to calcium sulfoaluminate cements, the mechanical strength was provided by the formation of abundant ettringite and possibly C-(A)-S-H gel-like phase that created a highly compact microstructure. Our findings suggest that mechanically activated Ca-rich CFBC fly ash can be successfully used as an alternative binder.

scholarly journals Development of the Strength of the Fluidized Bed Combustion Fly Ash Based Geopolymer in Time

2020 ◽  
Author(s):  
Natalia Paszek ◽  
Marcin Górski
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Curing Temperature ◽  
Hard Coal ◽  
Curing Process ◽  
Fluidized Bed Combustion ◽  
Curing Conditions ◽  
Fbc Fly Ash ◽  
Over Time

ThispaperpresentsastudyintothemechanicalbehaviourofFluidizedBedCombustion (FBC)fly ash-based geopolymer.FBCflyashisaby-product of a burning of a solid fuel (hard coal in case of this study) in a furnace at a low temperature. FBC fly ash is a type of a waste which is more difficult to recycle than pulverized fly ash.UsingFBCflyashin geopolymers offers one possible way to recycle it. The main goals of the investigation were to determine the influence of curing temperature and curing conditions on the strength of FBC fly ash-based geopolymer; to determine the changes of strength over time and the changes of the temperature inside the geopolymer during the curing process. Tests have shown that the strength of the geopolymer generally increases in line with the increase of a curing temperature. The compressive strength stabilizes after 5 days of curing and yet continues to gain extra strength over the longer term. Theflexuralbehaviourisnotmonotonicandthereforehardtopredict.The temperature inside the geopolymer rises rapidly until reaching around 27.5°C and then decreases steadily. Keywords: geopolymer, Fluidized Bed Combustion Fly ash, temperature, strength

scholarly journals Extending the Life Cycle of Cement Binders by Partially Replacing Portland Cement with Different Types Fluidized Bed Combustion Fly Ash

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 690
Author(s):  
Artur Łagosz ◽  
Tomasz Tracz ◽  
Radosław Mróz
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Sulfate Solution ◽  
Curing Temperature ◽  
Fluidized Bed Combustion ◽  
Sulfate Resistance ◽  
Granulated Blast Furnace Slag ◽  
Near Future ◽  
Fbc Fly Ash

A significant reduction in the CO2 emission associated with cement production is obtained by partially replacing Portland cement with supplementary cementing materials (SCM’s): e.g., siliceous fly ash or granulated blast furnace slag. In the near future, the limited availability of these materials will do more attractive to use ashes from combustion in fluidized bed boilers, which currently are mainly deposited in various landfills. Paper identifies the effect of Fluidized Bed Combustion (FBC) fly ash from both hard and brown coal combustion on the durability of mortars exposed to sodium and magnesium sulfate solution at different curing temperature: 20 and 5 °C. The evaluation was based on the results of long-term linear changes of mortar samples made with Portland cement and different amounts of FBC fly ash addition stored in a corrosive environment, as well as the evaluation of the type of formed corrosion products using XRD and microstructural studies (SEM/EDS). It has been shown that amount of FBC fly ashes used in binders significantly determines sulfate resistance of prepared cements as well as its chemical composition. By using fluidized ashes, the sulfate resistance of cement binders can be achieved with their content even of 15%.

Advancements in Properties of Cements Containing Pulverised Fly Ash and Nanomaterials by Blending and Ultrasonication Method (Review- Part II)

2019 ◽  
Vol 24 ◽  
pp. 37-44 ◽  
Author(s):  
Mehmet Serkan Kirgiz
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Review Paper ◽  
Setting Time ◽  
Heat Of Hydration ◽  
Strength Gain ◽  
Hydration Properties ◽  
Setting Times ◽  
Current Article

The second part of this review paper will explain Hydration properties of Portland pulverised fly ash cement section, Effect of nanomaterial on setting–time section, Effect of nanomaterial on heat of hydration section, Strength gain mechanisms for hardened Portland pulverised fly ash cement paste and mortar section, Effect of nanomaterial on compressive strength section, Effect of nanomaterial on flexural strength (Bending) section, and Conclusion section. Experiments reported include the setting–times, the heat of hydration, the compressive strength gain, and the flexural strength gain in the current article. According to the result, nanoparticles, especially the GNP, increase the heat of hydration of cement, and accelerate the time of setting evidently, both initial and final setting-time. The most effective nanoparticle on early compressive strength gain and flexural strength gain is the GNP. The article also points the effects of the nanoparticles on the strength gain of cement comprehensively. Consequently, the prominent cement technology can use the nanoparticles dispersed in liquid by ultrasonication method to increase the properties of cement based materials effectively.

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