Fly Ash Materials Research Articles

3D graphene/fly ash waste material for hybrid supercapacitor electrode: specific capacitance analysis

AbstractThe performance of supercapacitor energy storage is depending on the type of the material that is used as supercapacitor electrode. Graphene has been widely used as the base material for a lot of applications due to its remarkable properties. In this research, we try to combine 3D Graphene with waste material fly ash to be used as the electrode of supercapacitor. Fly ash is a residual material from burning pulverized coal in electric generation power plants which contain metal oxide materials such as iron oxide and aluminum oxide. This residual material might be usable as an electrode for supercapacitor due to its material contained. As the base material, the 3D graphene was successfully fabricated by using low pressure chemical vapor deposition (LPCVD) method and afterwards the fly ash was coated on the top of 3D graphene. The chemical properties and surface structure of the electrode material was studied by using Raman spectroscopy and field emission scanning electron spectroscopy (FESEM). 3 electrode systems were used to analyze the cyclic voltammetry results. According to the results, they show that the highest specific capacitance of 3D graphene/fly ash (FA) was about 0.025 F/cm2 at the lowest scan rate of 5 mV/s and it is recommended to use as the supercapacitor electrode.

Assessment and Characterization of Mine Waste and Fly Ash Material for Effective Utilization in Opencast Coal Mines

Coal is a major source of nonrenewable energy in India. Most of the Industries depend on the coal to meet the energy demand of the country. Coal mining is invariably associated with the generation of voids. The voids so generated are often filled with overburden (OB) and waste materials. To enhance the utilization, fly ash (FA) is also being used for filling the voids. However, these operations inevitably require excessive planning and control to minimize the environmental impact of mining. In order to evaluate the impact of backfilling the voids with coal mine wastes and fly ash, Overburden and fly ash materials have been collected from Talcher coalfield. The geotechnical characterization study of overburden (OB) sample and OB+30% fly ash samples have been carried out separately for backfilling. After addition of fly ash, it is observed that the permeability is increased but liquid limit, plastic limit, and plasticity index (PI) of the OB are decreased. The maximum dry unit weight of OB mixture decreases while optimum water content increases with the fly ash. The angle of internal friction of OB decreases after addition of the fly ash. Cohesion value of OB sample has not changed much after addition of the fly ash. The grain size analyses results show OB sample is poorly graded. The OB soil type is found to be poorly graded sand of low compressible clay (SP-CL). Similarly, the OB+30% fly ash soil type is of poorly graded sand of low compressible silty (SP-ML) type. The OB and OB+ 30% fly ash contain heavy metals such as Fe and Al in high quantity, mild concentrations of Zn, Cr, and Mn and low amounts of Cu, Co, As, and Se. B and Pb are found below the detection level. The decreasing order of heavy metals in the leachate samples observed to be Fe>Mn>Ni>Cu>Zn>Se>Co>Cd>Cr>As. The major mineral phases in OB and OB+30% fly ash samples are found to be quartz, kaolinite, muscovite, dickite, zinnwaldite, and illite.

Characterization of Fresh Sidoarjo Mud as Material on Geopolymer System

Sidoarjo mud is the alternative cementitious material which derived from a volcano mud eruption in Porong, Sidoarjo, East Java, Indonesia. The calcination of fresh sidoarjo mud in high temperature was known rich in the content of Si and Al that has similar chemical content with the material of OPC. However, the calcination process had caused the consumption of energy, time duration and cost in the production. To solve the problem, this study was required to investigate the fresh sidoarjo mud without the calcination process. However, material of FSM was analyzed to understand its feasibility as a material in geopolymer referring to the material of fly ash. The results showed that the material of FA consisted of quartz (SiO2), mullite (3Al2O3 2SiO2 or 2Al2O3 SiO2) and hematite. While, the material of FSM consisted of quartz (SiO2), mullite (3Al2O3 2SiO2 or 2Al2O3 SiO2), magnetite (Fe3O4), hematite (Fe2O3), and rutile (TiO2). The particle of FA was amorphous and sphere with the misty surface that caused the absorption of alkaline solution and reduced the workability on fresh geopolymer mortar. While the particle of FSM was the agglomerate irregular shape with the rough surface that also caused the absorption of alkaline solution and reduced the workability on fresh geopolymer mortar. The analysis of FTIR identified that the material FA and FSM had the stretching in the gel of Si-O-Al and Si-O-Si. The compressive strength reached optimum at the replacement of 5% FSM.

Effect of various commercial of Na2SiO3 on compressive strength of Fly ash-based alkaline activated mortar

This study aimed to assesses the effect of various commercial Na2SiO3 on the compressive strength (CS) of alkaline activated fly ash mortar (AAFM). The three mixture of alkaline activated mortar (AAM) C1, C2 and C3 were prepared from the source material of fly ash and alkaline activator solution (AAS). The initial AAS was comprised of NaOH (10M) and various grade of Na2SiO3. The various grades of Na2SiO3 were characterized by their SiO2/Na2O molar ratio of 2.0, 2.2, and 3.3, respectively. The sample from each mixture was characterized based on the CS and microstructure changes using useful tools of XRD and FTIR analysis. The results obtained indicated that the highest CS achieved among the three mixtures were 48.23MPa of mixture C2 prepared with SiO2/Na2O molar ratio of 2.2. This was mainly due to higher binder formation (N-A-S-H gel type) and a higher rate of reaction of the main source material. This result is in line with XRD and FTIR analysis results finding.

Investigation of mechanical properties in Al359 hybrid metal matrix composite reinforced with SiC and fly ash

In this study a modest attempt has been made to develop an aluminium based hybrid composite material reinforced with silicon carbide and five different volumetric compositions of fly ash material say 0%,2.5%,5%,7.5% and 10%. The samples were prepared by using stir casting method for achieving homogeneous dispersion of SiC ceramic material and fly ash over Al359 base matrix. The five different compositions of fly ash were selected to study the impact of aluminous and silicate particles available in fly ash over the enhancement of mechanical strength and hardness properties with response to reduction of elongation percentage in specimens. The tensile, flexural and hardness tests were carried out as per ASTM standards. The results of all the five different proportions of fly ash were compared and validated. The results indicate that the addition of fly ash in lower proportion enhance good properties by initiating good lubricity between Al359 and SiC. The addition of fly ash in higher percentage resulted in gradual reduction of strength and hardness properties because of more lubricity behaviour between Al359 and SiC.

Development of Ultra High Performance Concrete Using Fly Ash

The experimental work presented in this article examines the possibility of lowering the economic cost of UHPC. The UHPC were designed using the Linear Packing Density Model. After 7 days, the UHPC compressive strength exceeded 120 MPa. Level of compressive strength after 90 days reaching 150 MPa had been obtained with a lower dose of cement (700 kg/m3) and with the use of secondary raw materials (fly ash), without the use of dispersed reinforcement. The successful design and production proved that the use of secondary raw materials is possible, thereby decreasing the economic cost of UHPC production.

Fly Ash Effects on Fresh Concrete

Worldwide CO2 emission has been done by various agencies and reported their roots. The one most emerging and well known contributor of CO2 emission is the cement manufacturing. Now a days, cement manufacturing work out in practice are 1.7 x 109 t/year and it creates 7-8% worldwide greenhouse gas emission. Where the infrastructural growth depends on concrete production and concrete making process needs the binder material as a cement. Cement production has produces 900kg of CO2 per thousand kilogram of cement consumption and it’s definitely doubled in 2050, if other binder material inventions not happened. Therefore as considering a crucial role of binder material, fly ash material can play same or partial role as alternative material to cement. This study mainly introduces fresh fly ash concrete behavior for sustainable adoptability. Fly ash concrete more feasible (cheaper), scale down permeability, boost strength and influence other concrete properties. This paper is useful for assessing workability issues by providing 54 test results of slump cone and compaction factor test.

Mechanical Properties, Microstructure, and Chloride Content of Alkali-Activated Fly Ash Paste Made with Sea Water.

The aim of the present study is to investigate the potential of sea water as a feasible alternative to produce alkali-activated fly ash material. The alkali-activated fly ash binder was fabricated by employing conventional pure water, tap water, and sea water based alkali activating solution. The characteristics of alkali-activated materials were examined by employing compressive strength, mercury intrusion porosimetry, XRD, FT-IR, and 29Si NMR along with ion chromatography for chloride immobilization. The results provided new insights demonstrating that sea water can be effectively used to produce alkali activated fly ash material. The presence of chloride in sea water contributed to increase compressive strength, refine microstructure, and mineralogical characteristics. Furthermore, a higher degree of polymerization on the sea water-based sample was observed by FT-IR and 29Si NMR analysis. However, the higher amount of free chloride ion even after immobilization in sea water-based alkali-activated material, should be considered before application in reinforced structural elements.

Efficacy of green alternatives and carbon dioxide curing in reactive magnesia cement-bonded particleboards

This study demonstrated a low-carbon and value-added approach for upcycling waste wood formwork into reactive magnesia cement-bonded particleboards, in which green alternatives and carbon dioxide curing were employed to improve mechanical properties and reduce carbon footprint. Spectroscopic and thermogravimetric analyses showed that the replacement of pulverised fly ash and incinerated sewage sludge ash promoted the generation of magnesium silicate hydrates gel via pozzolanic-like reaction. The incorporation of mussel shell densified the microstructure as illustrated from scanning electron microscopy. Therefore, these modified particleboards presented satisfying flexural strength (>9 MPa) and thickness swelling (<2%). However, the spontaneous hydration of blast furnace slag manifested a competition against magnesia cement hydration and resulted in strength reduction. Furthermore, carbon dioxide curing promoted the transformation from magnesium hydroxide to additional magnesium carbonate and hydrated magnesium carbonates, which significantly enhanced early strength. However, the carbonation process consumed magnesium hydroxide, unavoidably suppressing the pozzolanic reaction. By contrast, blast furnace slag-incorporated samples showed synergetic hydration and carbonation. In summary, pulverised fly ash materials are promising substitutes in air curing condition, whereas blast furnace slag is suitable for accelerated carbonation of magnesia cement-based particleboards.

Compaction property prediction of mixed gangue backfill materials using hybrid intelligence models: A new approach

Solid backfill coal mining has become one of the main means of green mining in coal mines because of its ability to control surface subsidence and disposal of surface gangue. Mixed gangue backfill material (MGBM) is the key factor for stratum control in solid backfill mining, and its compact mechanical performance directly affects the efficiency of backfill mining. In order to better carry out backfill mining design and backfill effect evaluation, a new hybrid artificial intelligence model integrating support vector machines (SVM), differential evolution algorithm (DE) and gray wolf optimization algorithm (GWO) is proposed to predict the compaction property of MGBM. The cement, lime and fly ash materials are selected to be mixed with gangue backfill materials and a large number of compaction tests using a self-made circular cylinder barrel are carried out to provide the dataset for the DGWO-SVM hybrid model. The input variables of this model include cement content, lime content, fly ash content and overburden stress, and the output variable of the model is the compaction property of MGBM. The performance of the DGWO-SVM model is evaluated by R2, MAE and RMSE. The predictive results indicate that the DGWO-SVM hybrid model can accurately predict the compaction property of MGBM, and the R2 of the training set and the testing set are 0.9518, 0.9137. Meanwhile, the relative importance of each input variable is implemented using the MIV method, and the importance scores of cement content, lime content, fly ash content and overburden stress are 0.3266, 0.0738, 0.2448, 0.3548, respectively. The research results can provide guidance for the optimization design of solid backfill mining.

Effect of admixtures and supplementary cementitious material on mechanical properties and durability of concrete

AbstractWe studied the effects of superplasticizer (SP) (PCE1 and PCE2), air‐entraining admixtures (AEA), and supplementary cementitious material (silica fume and fly ash) on the mechanical and durability properties of concrete samples. Eight concrete mix designs were prepared. The first six concrete mix design contained similar aggregates, PCE2 SP, AEA, 350 kg/m3cement, and water to cement ratio equal to 0.38, and one of the mentioned mix design was selected as control samples with water to cement ratio equal to 0.57, without PCE2 SP and AEA. We used a different quantity of PCE2 SP and AEA and replaced the fly ash or silica fume as part of cement in two of the mentioned mix designs. The last two concrete mix designs studied the effect of PCE1 SP and AEA on freezing and thawing of concrete mix design. Adding PCE2 SP in concrete mix design increased compressive strength at age 11, 42, and 90 days sharply and reduced the depth of water penetration at the age of 28 and 90 days compared to the control sample. Using simultaneous PCE2 and AEA in concrete mix design did not improve compressive strength significantly and increased slightly depth of water penetration compared to only using PCE2. However, increasing the quantity of AEA to 5% improved both compressive strength and reduced depth of water penetration. In the second group of concrete mix design, adding both PCE1 and AEA increased the number of resistible freezing and thawing cycles of concrete. Side chain length and molecular weight of PCE1 and PCE2 SPs had no important effect on the compressive strength and performance properties of concrete.

Economical Design of Ash Bund for Disposal of Wonder Material- Fly Ash

Fly ash is waste by product generated from a thermal power plant in huge quantity and its disposal is a majorproblem. As on today it is being disposed of either by dumping in open land, by refilling in low lying areas ordischarging water mix slurry form in impounding pond, river or sea. But in all of such methods it has a negativeimpact on environment.[1][3][7] Realizing these negative effects of fly ash on land and water; Government ofIndia and Government of Maharashtra, issued a notification directing all fly ash producer to prepare an actionplan to use fly ash fully. Consumption of electricity is indexing of developing country. Major source ofelectricity generation is thermal power plants and other resources are very poor in India. India is one of thefastest growing and developing country; generation of fly ash as waste material is increasing every year due toincreased demand of electricity. But it is unfortunate that still percentage utilisation of fly ash in India is verylow and most of the fly ash has to be disposed off for storage.[8] Keeping this in mind an effort is made byauthors to design bund for disposal of wonder material fly ash using locally available Black cotton soil ashearting material and murum as casing material for initially built minimum required height fly ash bund andafterwards height of bund is successively increased by using stored fly ash as hearting material and murum ascasing material in bund. This is the safe, economical and eco friendly storage of disposed fly ash.

Performance evaluation of mechanical properties of self-compacting concrete using artificial neural network

This experimental study was undertaken to investigate the effects of using local materials (cement, fly ash, super-plasticizer, coarse aggre-gate, and sand) on the mechanical properties of Self-Compacting Concrete (SCC). For this purpose, a total of 31 mixtures of SCC were prepared by the neural network design methods. Furthermore, based on the experimental results, the neural network model-based clear for-mulations were developed to predict the mechanical properties of SCC. The test results have shown that mineral admixtures were very effective on hardened properties of SCC. In addition, it was found that the developed model by using neural network appeared to have a high predictive capacity of hardened properties of SCC with respect to regression and experimental. Â

Experimental Examination on the Effect of Composite Amalgam with Fly ash &amp; E-glass Materials with Al-8011Subjected to Mechanical Characterization

The main objective of this experimental examination is to accentuate the salient effect of mixtures viz., E-glass and Fly ash based on the characterization of prominent mechanical properties of Al 8011 hybrid amalgamated composites. The prominent alloy Al-8011 amalgamated with particulates of E-glass and fly ash materials have been fabricated by using graphite die for the method of casting. The metal matrix composite is fabricated for dissimilar configuration of the particulates of E-glass and fly-ash by changing E-glass with constant fly ash. The hybrid composite samples have been fabricated as per genuine prerequisite of ASTM standards or conditions to accomplish pertinent tensile and compression tests.

A study of the influence of crystal component on the reactivity of low-calcium fly ash in alkaline conditions based on SEM-EDS

The use of fly ash to improve concrete performance has increased around the world in recent decades. However, the engineering application of fly ash remains limited by its heterogeneity and variability. This paper presents a developed approach for comprehensive characterisation of fly ash material properties based on scanning electron microscopy–energy-dispersive X-ray spectroscopy full-element mapping with image analysis. The chemical compositions, mineralogical and amorphous phase assemblage and specific surface area of each phase can be visually analysed and quantified. Analysis reveals that the phase assemblage of fly ash is affected by its combustion conditions. Although a wide distribution of crystalline mullite can be found in fly ash particles, crystalline quartz is usually covered by amorphous silicate. The characterisation approach developed in this study is used to investigate the influence of crystal components on kinetic properties of various phases of fly ash in alkaline conditions. The results show that crystalline mullite affects the kinetic properties of Al-silicate glass and glass-mullite intermixtures.

Reutilisation of coal gangue and fly ash as underground backfill materials for surface subsidence control

To address the environmental problems caused by solid waste while promoting the sustainable development of mines, gangue and fly ash can be used as underground backfill materials to achieve the comprehensive utilisation of solid waste mining resources. We measured the compressive deformation characteristics of samples with different ratios of gangue to fly ash and analysed their stress-strain relationship and associated changes in their porosities using a YAS-5000 servo testing machine and a homemade compression apparatus. Moreover, we revealed the mechanisms of deformation resistance of gangue and fly ash from both a macro and meso perspective and determined that the optimal ratio of gangue to fly ash is 0.35. In addition, taking the backfill face in Coal Mine as an example, mixed materials of gangue and fly ash at a ratio of 1:0.35 were backfilled into a goaf. After mining of the working face, the surface only sank by 170 mm approximately. This method not only effectively disposes of solid wastes, i.e., gangue and fly ash, on a large scale but also controls surface subsidence to protect adjacent buildings and structures. Therefore, the coordinated development of coal resource mining and environmental protection are realised.

CHARACTERIZATION OF SIDOARJO MUD AS BASE MATERIAL IN GEOPOLYMER

Sidoarjo mudflow (SM) is an alternative source material in the construction which is generated from natural disasters of volcano mud flow in Porong, Sidoarjo, East Java, Indonesia. This source material is classified as replacement cementing material (RCM) due to rich of Si, Fe and Al content. In addition, high Si and Al contents in SM material are considered to be able to replace FA as a base material in geopolymer binder. However, the calcination temperature is required to reduce volatile and impurities in SM material. The source material after calcination process is termed as volcanic meta ash (VMA). This study aims to investigate the feasibility of VMA material as an alternative source material in geopolymer binder. The results mention that Si and Al contents of VMA material are 1.5 and 1.3 times higher than fly ash (FA) material. The crystalline of quartz and mullite and chemical bonding of Si-O-Si and Si-O-Al in VMA material is more than FA material. VMA material has the particle of irregular agglomerate shape and rough surface.

Modeling for the use of waste materials (Bottom ash and fly ash) in soil stabilization

Coal thermal power plants generate a huge amount of waste in the form of bottom ash and fly ash which is disposed of every year in large quantity. It has harmful effects as environmental pollution, money-wasting for land acquisition and respiratory problems. The best option is to use these materials in the construction of infrastructure, but an assessment is mandatory for the materials before their application. This study is conducted to show the improvement in the strength of soil by adding the proportion of bottom ash and fly ash in the soil. A total of 21 samples were made and tested with different ash proportions. Atterberg’s limits test, Proctor test, and California Bearing Ratio (CBR) tests were conducted to check the strength of different samples. Optimum content was identified as 12% bottom ash, 18% fly ash and 70% soil. At this proportion, the California Bearing Ratio value was 13.7% which is highest among all and decrease in the plasticity characteristics was observed due to the filling of maximum voids with fine particles of the ash in the flocculated structure of the soil.

Speciation analysis of inorganic As and Sb in urban dust using slurry sampling and detection by fast sequential hydride generation atomic absorption spectrometry.

In this work, a methodology for chemical speciation analysis of inorganic As and Sb in urban dust using slurry sampling and detection by fast sequential hydride generation atomic absorption spectrometry is proposed. Doehlert design and desirability function were used to find the optimum conditions for hydride generation (1.0molL-1 HCl and 0.9%mv-1 NaBH4). The accuracy of the analytical method was evaluated by analysis of reference material fly ash (BCR 176R), addition and recovery tests for inorganic As species, and comparison of independent methods for Sb determination in urban dust samples. The determination of the total concentrations of As and Sb and their inorganic species presented good accuracy, between 80 ± 1 and 101 ± 6%. Precision was expressed as the relative standard deviation and was better than 4.7% (n = 3). The limit-of-quantification values were 0.23 and 1.03mgkg-1 for As and Sb, respectively. The methodology was applied to eight samples of dust collected in an urban area of Salvador and Jaguaquara cities, Bahia, Northeast, Brazil, with an aerodynamic size lower than 38μm. Concentrations of pentavalent inorganic species (iAs5+ and iSb5+) in relation to trivalent species (iAs3+ and iSb3+) were found in urban dust collected in the city of Salvador, which are regarded as more toxic for both elements. The enrichment factor and geoaccumulation index (Igeo) values showed that for some samples, the concentrations of iAs and iSb presented strong enrichment and, and regarding environment, strong to moderately polluted by iAs and iSb, with an indication of anthropogenic contributions. The occurrence of these inorganic constituents in the urban area of Salvador can be related with intense industrial activities and vehicular traffic.

Implementation Of Permen Esdm No. 17/2012 As A Solution Between Mineral Businessesand Conservation Karst Zone In Indonesia

Cement is powder made from lime and other materials used to make concrete, glue bricks or make walls (KBBI, 2008). Cement is a material that is hydraulic in nature, that is, a material which will undergo a hardening process in its mixing with water or acid solution. The raw materials for making cement include: clinker / slag of cement as much as 70% - 95% (the results of the combustion of limestone, silica sand, iron sand and clay), 5% gypsum and other additional materials (limestone, pozzolan, fly ash and etc). Along with the increase in infrastructure development which is the focus of the Government at this time, the need for building materials, especially cement, has increased. This increase in demand has made cement companies increase production, which in turn will also reduce the limestone reserves that exist in nature. Geological resources consist of mineral resources, energy resources, water resources, and landscapes. Limestone as one of the dominant raw materials for making cement is a mineral and landscape resource that must be protected. The Ministry of Energy and Natural Resources since 2012 has issued regulations relating to the use and protection of Karst Landscape Areas (Permen ESDM No. 17 of2012). Protection of the Karst Landscape Area aims to protect its function as a natural regulator of the water system and its unique / scientific value in the development of science. Meanwhile, the delineation of utilization efforts as minerals and industrial raw materials is regulated so that it does not disturb the conservation zone. Expected with the regulations (Permen ESDM No. 17 of 2012) can be a solution for the use and protection of the Karst Landscape in Indonesia.