Additional Aging Effect after Carbonation Process of Fly Ash Based Eco-Materials

The purpose of this study is to enhance the mechanical strength of specimens containing fly ash from fluidized bed type boiler, which the recycling rate will be eventually increased. Specimens containing fly ash in a certain portion were made and aged for 3, 14, and 21 days. The carbonation process under the super critical condition was performed to enhance the mechanical property of specimens by filling the voids and cracks existing inside cement specimen with CaCO3 reactants. The additional aging effect after the supercritical carbonation process on mechanical strength of specimens was also investigated by comparing the compressive strength with and without 7 day extra aging. Carbonation under the supercritical condition and additional 7 day aging was very effective for enhancement of mechanical strength and compressive strength increased by 44%, which reached up to 88MPa.

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

Materials ◽

10.3390/ma13010141 ◽

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.

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Effect of Reaction Conditions on Pore Configuration and Mechanical Property for Porous Hydroxyapatite Prepared by Polymer Sponge Method

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1567 ◽

2007 ◽

Vol 336-338 ◽

pp. 1567-1570 ◽

Cited By ~ 1

Author(s):

Sang Ho Min ◽

Hyeong Ho Jin ◽

B.S. Jun ◽

Ik Min Park ◽

Hong Chae Park ◽

...

Keyword(s):

Mechanical Property ◽

Compressive Strength ◽

Mechanical Strength ◽

Porous Structure ◽

Pore Wall ◽

Pore Morphology ◽

Reaction Conditions ◽

Average Pore ◽

Porous Hydroxyapatite ◽

Pore Wall Thickness

Porous HAp scaffolds have been prepared by using the slurry including HAp and magnesia based on the replication of polymer sponge substrate. The influence of HAp and MgO content in slurry on the pore morphology and size, and density, porosity, and mechanical strength of porous HAp scaffolds was investigated. The obtained scaffolds with average pore sizes ranging 150 to 300 μm had open, relatively uniform, and interconnected porous structure regardless of HAp and MgO content. As the MgO content increased, the pore network frame of scaffolds became to be relatively stronger, even though the pore size was not much changed. The compressive strength of the scaffolds increased rapidly with the increase of MgO content at a fixed HAp content because of increasing the pore wall thickness and density of the scaffolds. As a result, the porosity, density, and compressive strength of the porous HAp scaffolds scaffolds prepared by the sponge method were significantly affected by the addition of MgO.

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Mechanical and Microstructural Characterization of Quarry Rock Dust Incorporated Steel Fiber Reinforced Geopolymer Concrete and Residual Properties after Exposure to Elevated Temperatures

Materials ◽

10.3390/ma14226890 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6890

Author(s):

Muhammad Ibraheem ◽

Faheem Butt ◽

Rana Muhammad Waqas ◽

Khadim Hussain ◽

Rana Faisal Tufail ◽

...

Keyword(s):

Mechanical Properties ◽

Weight Loss ◽

Compressive Strength ◽

Fly Ash ◽

Mechanical Strength ◽

Elevated Temperatures ◽

Strength Properties ◽

Steel Fibers ◽

Geopolymer Concrete

The purpose of this research is to study the effects of quarry rock dust (QRD) and steel fibers (SF) inclusion on the fresh, mechanical, and microstructural properties of fly ash (FA) and ground granulated blast furnace slag (SG)-based geopolymer concrete (GPC) exposed to elevated temperatures. Such types of ternary mixes were prepared by blending waste materials from different industries, including QRD, SG, and FA, with alkaline activator solutions. The multiphysical models show that the inclusion of steel fibers and binders can enhance the mechanical properties of GPC. In this study, a total of 18 different mix proportions were designed with different proportions of QRD (0%, 5%, 10%, 15%, and 20%) and steel fibers (0.75% and 1.5%). The slag was replaced by different proportions of QRD in fly ash, and SG-based GPC mixes to study the effect of QRD incorporation. The mechanical properties of specimens, i.e., compressive strength, splitting tensile strength, and flexural strength, were determined by testing cubes, cylinders, and prisms, respectively, at different ages (7, 28, and 56 days). The specimens were also heated up to 800 °C to evaluate the resistance of specimens to elevated temperature in terms of residual compressive strength and weight loss. The test results showed that the mechanical strength of GPC mixes (without steel fibers) increased by 6–11%, with an increase in QRD content up to 15% at the age of 28 days. In contrast, more than 15% of QRD contents resulted in decreasing the mechanical strength properties. Incorporating steel fibers in a fraction of 0.75% by volume increased the compressive, tensile, and flexural strength of GPC mixes by 15%, 23%, and 34%, respectively. However, further addition of steel fibers at 1.5% by volume lowered the mechanical strength properties. The optimal mixture of QRD incorporated FA-SG-based GPC (QFS-GPC) was observed with 15% QRD and 0.75% steel fibers contents considering the performance in workability and mechanical properties. The results also showed that under elevated temperatures up to 800 °C, the weight loss of QFS-GPC specimens persistently increased with a consistent decrease in the residual compressive strength for increasing QRD content and temperature. Furthermore, the microstructure characterization of QRD blended GPC mixes were also carried out by performing scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS).

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Effect of Mechanical Activation of Fluidized Bed Fly Ash on Geopolymer Properties

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.288.51 ◽

2019 ◽

Vol 288 ◽

pp. 51-58

Author(s):

Gendenjamts Oyun-Erdene ◽

Jadambaa Temuujin

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Mechanical Activation ◽

Sodium Hydroxide ◽

Fluidized Bed ◽

Sodium Silicate ◽

Sodium Hydroxide Solution ◽

Chemical Activation ◽

Weight Ratio ◽

Particle Size Reduction

This paper is focused on the elucidation of mechanical activation effect of circulating fluidized bed combustion fly ash (Amgalan Thermal Station, Mongolia) on mechanical properties of geopolymers. Fluidized bed fly ash was mechanically activated for 15-120 minutes with a vibratory mill. The effect of mechanical activation was quite visible on the particle size reduction and on the degree of amorphization.Geopolymer samples were prepared from the raw and milled fluidized bed fly ashes by alkaline activation. Chemical activation was performed with 10M sodium hydroxide solution, as well as solutions containing a mixture of sodium silicate and sodium hydroxide with a weight ratio of 2:1. The geopolymer cubic specimens were cured at 70°C for 24 hrs and their 7 days uniaxial compressive strength was measured. After curing and drying, the bulk density, water absorption and apparent porosity of geopolymer samples were evaluated.X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetry-differential thermal analysis (TGA-DTA) have been used for the structural characterization of the CFA and the resulting geopolymers. The highest compressive strength of 32.4 MPa was achieved for the fly ash milled for 30 minutes and activated with the solution containing the sodium silicate and 10M sodium hydroxide at a weight ratio of 2:1. Non-milled CFA based geopolymers showed the compressive strength of 16.2 MPa after activation with the same solution. Mechanical activation resulted in an increase in the reactivity of the fluidized bed fly ash and that enhances the geopolymerization reactions.

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Investigation and Improvement on the Mechanical Property of Cement Mortar

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.253-255.482 ◽

2012 ◽

Vol 253-255 ◽

pp. 482-488

Author(s):

Hai Bo Zhang ◽

Xue Mao Guan ◽

Hai Tao Shang

Keyword(s):

Mechanical Property ◽

Contact Angle ◽

Compressive Strength ◽

Fly Ash ◽

Silica Fume ◽

Cement Mortar ◽

Hydrophobic Surface ◽

Cement Matrix ◽

Weak Interface ◽

Rubber Surface

This paper examined the mechanical property of rubber mortars with different amount of rubber granules addition and the influence of fly ash, slag and silica fume. The increase of rubber granules results in the decrease in compressive and flexural strength of rubber mortar, but increases the ratio of flexural to compressive strength. The fly ash, slag and silica fume are useful for improving the mechanical property of mortar. The examined contact angle of water against rubber is 99.5°, which suggests the rubber surface is hydrophobic, and the hydrophobic surface interprets the weak interface between rubber and cement matrix.

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Cement-fly ash mortars durability, with fly ash from fluidized bed boilers and conventional combustion, exposed to aggressive environment influence

MATEC Web of Conferences ◽

10.1051/matecconf/201817402006 ◽

2018 ◽

Vol 174 ◽

pp. 02006 ◽

Cited By ~ 1

Author(s):

Elżbieta Janowska-Renkas ◽

Jolanta Kowalska ◽

Grzegorz Janus ◽

Agnieszka Kaliciak

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Mass Loss ◽

Fluidized Bed ◽

Total Porosity ◽

Environment Impact ◽

Fly Ashes ◽

Aggressive Environment ◽

Cement Mortars ◽

The Impact

The study shows results of research on the aggressive environment impact (1, 3 and 5% HCl solution) on durability of cement mortars with fraction from 30 to 45% by mass of fly ashes from the fluidized bed combustion (FBC fly ash) and conventional fly ashes used separately and in the form of a mixture. The impact of aggressive environments on durability of cement and ash mortars was tested for aperiod of 365 days, by testing the compressive strength, linear changes, mass loss and porosity. It was demonstrated that mortars with the content of FBC fly ashes, after 365 days of tests showed the higher resistance to aggressive environment impact. It is confirmed by e.g. their higher compressive strength, and thus the reduced total porosity. Reduction of total porosity content (<50 nm) was accompanied by the increased compressive strength, which in the aqueous environment was in favour of cement mortars, and in the aggressive environment in favour of cement and ash mortars. It was demonstrated that the content of pores < 200 nm was lower for mortars with FBC fly ashes and mixtures of ashes regardless of environment the mortars were stored in. A beneficial impact of FBC fly ashes was found on physical properties of mortars, i.e. reduction of the shrinkage, lower mass loss and reduced destruction of mortars in the acid corrosion environment. That effect was especially beneficial for the mortar with higher (45% by mass) content of FBC fly ashes, regardless of aggressive character of the environment.

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

Polymers ◽

10.3390/polym13152527 ◽

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.

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Performance of Ground Granulated Blast-Furnace Slag and Coal Fly Ash Ternary Portland Cements Exposed to Natural Carbonation

Materials ◽

10.3390/ma14123239 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3239

Author(s):

Rosa Abnelia Rivera ◽

Miguel Ángel Sanjuán ◽

Domingo Alfonso Martín ◽

Jorge Luis Costafreda

Keyword(s):

Compressive Strength ◽

Blast Furnace ◽

Fly Ash ◽

Blast Furnace Slag ◽

Coal Fly Ash ◽

Portland Cements ◽

Carbonation Process ◽

Granulated Blast Furnace Slag ◽

Natural Carbonation ◽

Furnace Slag

Ternary Portland cements are new cementitious materials that contain different amounts of cement replacements. Ternary Portland cements composed of granulated blast-furnace slag (GBFS), coal fly ash (CFA), and clinker (K) can afford some environmental advantages by lowering the Portland cement clinker use. Accordingly, this is an opportunity to reduce carbon dioxide emissions and achieve net-zero carbon emissions by 2050. Furthermore, GBFS and CFA possess pozzolanic properties and enhance the mechanical strength and durability at later ages. Compressive strength and natural carbonation tests were performed in mortar and concrete. Cement-based materials made with GBFS and/or CFA presented a delay in the compressive strength development. In addition, they exhibited lower carbonation resistance than that of mortar and concrete made with plain Portland cements. Concrete reinforcement remains passive in common conditions; however, it could be corroded if the concrete pore solution pH drops due to the carbonation process. Service life estimation was performed for the ternary cements regarding the carbonation process. This information can be useful to material and civil engineers in designing concretes made with these ternary cements.

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Preparation of Sulphoaluminate-Alite Composite Mineralogical Phase Cement Clinker from High Alumina Fly Ash

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.334-335.421 ◽

2007 ◽

Vol 334-335 ◽

pp. 421-424 ◽

Cited By ~ 11

Author(s):

Jin Hong Li ◽

Hong Wen Ma ◽

Hong Wei Zhao

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Flexural Strength ◽

Mechanical Strength ◽

Hydration Product ◽

Xrd Analysis ◽

Cement Clinker ◽

High Alumina ◽

Sem Observation ◽

Mineralogical Phase

Sulphoaluminate-alite cement (SAAC) was successfully prepared from high alumina fly ash. XRD analysis indicated that the optimal mineralogical phase of cement clinker was obtained under condition of MG=1.05, MS =0.95 at 1300oC, and C4A3 S reached the strongest intensity and is 58.73% in the phase of calcined clinckers. SEM observation showed that C4A3 S are well developed into regular diamond/hexagon-shaped crystal with the size of 1~3.5 μm in the clinker. Hydrated clinker exhibited its new formed dominant phases in AFt, C-S-H and Afm. Pillar shaped AFt and sheet shaped AFm coexisted among the colloidal C-S-H substrate. It is demonstrated that the prepared cement shows a compressive strength of 27 MPa (1d), 36 MPa (3d), 49 MPa (28d), and flexural strength of 5.9 MPa (1d), 5.9 MPa (3d), 6.1 MPa (28d), indicated that the hydration product owned a good mechanical strength at early ages and increased steadily in the later stages.

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Effect of Solid to Liquid Ratio on the Mechanical and Physical Properties of Fly Ash Geopolymer without Sodium Silicate

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.625.46 ◽

2014 ◽

Vol 625 ◽

pp. 46-49 ◽

Cited By ~ 14

Author(s):

Rosniza Hanim Abdul Rahim ◽

Khairun Azizi Azizli ◽

Zakaria Man ◽

Tia Rahmiati ◽

Lukman Ismail

Keyword(s):

Mechanical Property ◽

Compressive Strength ◽

Fly Ash ◽

Physical Properties ◽

Silicate Solution ◽

Strength Development ◽

Alkali Activation ◽

Liquid Ratio ◽

Mechanical And Physical Properties ◽

Solid Liquid

Geopolymer is produced from the alkali activation of materials rich in Si and Al with addition of silicate solution in order to improve the mechanical property. Limited research has been done with the absence of silicate solution in the geopolymerization process by varying solid/liquid ratio and on how it works for that condition on mechanical and physical properties. This paper presents an investigation on the mechanical and physical properties of fly ash based geopolymer by varying solid to liquid ratio using sodium hydroxide as the only activator. In addition, the strength development also been investigated. The samples were prepared using 50mm x 50mm x 50mm mould and cured at an elevated temperature (60oC). It can be observed that the optimum compressive strength and density were obtained at solid/ liquid ratio of 4. In addition, the compressive strength of fly ash based geopolymer for all the solid to liquid ratio increased until 14 days and started to decrease later.

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