scholarly journals Statistical model used to assessment the sulphate resistance of mortars with fly ashes

2019 ◽  
Vol 9 (1) ◽  
pp. 536-544
Author(s):  
Julia Marczewska ◽  
Monika Jaworska
Keyword(s):  
Power Plants ◽  
Xrd Analysis ◽  
Sodium Sulphate ◽  
Cement Industry ◽  
Ternary Mixtures ◽  
Partial Replacement ◽  
Fly Ashes ◽  
Gibbs Triangle ◽  
Research Plan ◽  
Positive Effect

AbstractThe use of low (LCFA) and high (HCFA) calcium fly ashes in the cement industry allows the implementation of European Union proposals on waste management and energy saving. However, the possibility of using HCFA is limited, because the properties of such waste from coal-fired power plants must comply with national regulations. The paper shows the effect of partial replacement of Portland cement (OPC) by these fly ashes on the resistance of the sulphate attack of the mortars immersed in a 5% solution of sodium sulphate. In order to determine the optimal amount of ash additive, a research plan was designed using statistical methods using the Gibbs triangle for mixtures. Samples of control mortars of OPC, binary mixtures of HCFA or LCFA and ternary mixtures of HCFA/LCFA were made. The composition of the blends was designed in accordance with the statistical plan of the experiment for mixtures. The testing program included linear strains, compressive strength and microstructure tests using SEM with EDXA and XRD analysis. The results of laboratory tests and statistical analyzes have shown that fly ash has a positive effect on the sulphate resistance of cementitious composites.

Eco-Friendly Basalt Fiber Reinforced Cement Composites (BFRC) Containing Waste Copper As Partial Replacement For Sand And Cement

2021 ◽  
Author(s):  
Mohammed Najı Ahmed Abu Aeshah ◽  
Gökhan Kaplan
Keyword(s):  
Basalt Fiber ◽  
Drying Shrinkage ◽  
Copper Slag ◽  
Sodium Sulphate ◽  
Partial Replacement ◽  
Taguchi Optimization ◽  
Freeze Thaw ◽  
Reinforced Cement ◽  
Strength And Durability ◽  
Positive Effect

Abstract In this study, the use of copper slag and aggregate together with basalt fiber in cement-based composites was studied. It was aimed to contribute to the ecosystem by using copper waste, which is an environmental problem, in cement-based composites. In addition, the effect of basalt fiber on the strength and durability properties of composites was investigated. Taguchi optimization was carried out for cement-based composites. In this context, Taguchi L18 matrix was used. Copper slag was used at rates of 0, 7.5% and 15%, and copper aggregate at rates of 0, 25% and 50%. Basalt fibers of 6 and 12 mm length were used at the rates of 1%, 2% and 3%. The w/b ratios of the mixtures were chosen as 0.40, 0.50 and 0.60. Durability tests such as permeability, freeze-thaw and sulphate resistance with fresh and hardened mortar properties were performed on 18 different mixtures. In terms of the 7, 28 and 91-day flexural and compressive strength of the mixtures, the use of 1% of 6 mm long fiber in the mixtures with a w/b ratio of 0.40 provided more positive results. In terms of freeze-thaw resistance, it is necessary to use 3% of 6 mm long fiber in mixtures with 0.40 w/b. The use of 7.5% copper slag reduced the water penetration depth. The use of 15% copper slag in mixtures affected by sodium sulphate reduced the expansion values. Since the increase in the ratio of copper aggregate decreased the aggregate volume, it caused the drying shrinkage values to increase. As a result, it was observed that copper slag has a more positive effect than copper aggregate for the strength and durability of composites. However, by using 25% of copper aggregate by sacrificing some features, it can contribute to the environment and ecosystem. The use of basalt fiber with a length of 6 mm and a ratio of 1% increased the mechanical properties, while the use of 3% contributed significantly to the freeze-thaw resistance. It was determined that copper wastes contribute to the environment and ecosystem by using them instead of cement and aggregate.

scholarly journals Process Kinetics of the Carbonation of Fly Ashes: A Research Study

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 253
Author(s):  
Marian Jacek Łączny ◽  
Sebastian Iwaszenko ◽  
Adam Smoliński
Keyword(s):  
Fluidized Bed ◽  
Power Plants ◽  
Cement Industry ◽  
Free Calcium ◽  
Fluidized Bed Combustion ◽  
Drying Process ◽  
Fly Ashes ◽  
Process Kinetics ◽  
Concrete Production ◽  
Kinetics Of

The aim of the paper is to present the results of research on the carbonation process kinetics of coal combustion ashes originating from fluidized bed boilers used in power plants. Based on the thermogravimetric analysis (TGA), the hypothesis that carbon dioxide is bounded by the mineral substances (calcium compounds) in the fly ashes was confirmed. Determining the kinetic parameters of the carbonation of fly ashes requires simultaneously taking into consideration the kinetics of the drying process of the sample. The drying process of the sample masks the effect of the reaction of CO2 with calcium compound. Unlike the ashes generated in pulverized fuel boilers, fly ashes contain irregular amorphic mineral components or poorly crystalized products of complete or partial dehydroxylation of claystone substance present in shale formations constituting the gangue as well as anhydrite (CaSO4), a desulfurization product. The content of free calcium oxide (CaO) in such ashes ranges from a few to several percent, which is a significant obstacle considering their use in cement and concrete production as type II admixtures understood to be inorganic grained materials of pozzolanic or latent hydraulic properties. The paper presents effective mechanisms which reduce the content of free CaO in ashes from Fluidized Bed Combustion (FBC) boilers to a level that allows their commercial utilization in the cement industry.

A Review on Utilization of Fly- Ash and Pond-Ash as a Partial Replacement of Cement in Concrete Mix Design

2018 ◽  
pp. 413-418
Author(s):  
Harshkumar Patel ◽  
Yogesh Patel
Keyword(s):  
Fly Ash ◽  
Electricity Generation ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Strength Test ◽  
Partial Replacement ◽  
Pond Ash ◽  
Research Activities ◽  
Ash Disposal

Now-a-days energy planners are aiming to increase the use of renewable energy sources and nuclear to meet the electricity generation. But till now coal-based power plants are the major source of electricity generation. Disadvantages of coal-based thermal power plants is disposal problem of fly ash and pond ash. It was earlier considered as a total waste and environmental hazard thus its use was limited, but now its useful properties have been known as raw material for various application in construction field. Fly ash from the thermal plants is available in large quantities in fine and coarse form. Fine fly ash is used in construction industry in some amount and coarse fly ash is subsequently disposed over land in slurry forms. In India around 180 MT fly is produced and only around 45% of that is being utilized in different sectors. Balance fly ash is being disposed over land. It needs one acre of land for ash disposal to produce 1MW electricity from coal. Fly ash and pond ash utilization helps to reduce the consumption of natural resources. The fly ash became available in coal based thermal power station in the year 1930 in USA. For its gainful utilization, scientist started research activities and in the year 1937, R.E. Davis and his associates at university of California published research details on use of fly ash in cement concrete. This research had laid foundation for its specification, testing & usages. This study reports the potential use of pond-ash and fly-ash as cement in concrete mixes. In this present study of concrete produced using fly ash, pond ash and OPC 53 grade will be carried. An attempt will be made to investigate characteristics of OPC concrete with combined fly ash and pond ash mixed concrete for Compressive Strength test, Split Tensile Strength test, Flexural Strength test and Durability tests. This paper deals with the review of literature for fly-ash and pond-ash as partial replacement of cement in concrete.

Influence of Different Mineral Precursors on the Properties of Fly Ash Based Alkali-Activated Mortars

2018 ◽  
Vol 761 ◽  
pp. 73-78 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Chemical Composition ◽  
Coal Combustion ◽  
Pure Aluminum ◽  
Partial Replacement ◽  
Black Coal ◽  
Fly Ashes ◽  
Final Composition ◽  
Alkali Activated

Alkali-activated materials based on fly ash are widely developed and also produced on the present. Some of fly ashes are not suitable for production of alkali-activated materials because of their inconvenient chemical composition. Alumina-silicates are the most important components that are needed to accomplish the successful reaction. The proper content of amorphous phase of alumina-silicates and its proportion as well should be provided for the final composition of alkali-activated materials. The influence of pure aluminum oxide powder as well as raw milled natural perlite on mechanical properties and durability of alkali-activated mortars was investigated. These minerals were used as partial replacement of fly ash coming from black coal combustion. In addition, the mortars were prepared by using different alkali activators.

scholarly journals Partial Replacement of Cement with Waste Paper Sludge Ash

2021 ◽  
Vol 9 (11) ◽  
pp. 1975-1983
Author(s):  
Shahid Bashir
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Water Absorption ◽  
Cement Industry ◽  
Waste Paper ◽  
Partial Replacement ◽  
Dry Density ◽  
Paper Sludge ◽  
Paper Sludge Ash ◽  
Sludge Ash

Abstract: Cement production is one of the sources that emit carbon dioxide, in addition to deforestation and combustion of fossil fuels also leads to ill effects on environment. The global cement industry accounts for 7% of earth’s greenhouse gas emission. To enhance the environmental effects associated with cement manufacturing and to constantly deplore natural resources, we need to develop other binders to make the concrete industry sustainable. This work offers the option to use waste paper sludge ash as a partial replacement of cement for new concrete. In this study cement in partially replaced as 5%, 10%, 15% and 20% by waste paper sludge ash in concrete for M25 mix and tested for compressive strength, tensile strength, water absorption and dry density up to the age of 28days and compared it with conventional concrete, based on the results obtained, it is found that waste paper ash may be used as a cement replacement up to 5% by weight and the particle size is less the 90µm to prevent reduction in workability. Keywords: slump test, Compressive strength, split tensile strength, water absorption test, Waste Paper Sludge Ash Concrete, Workability.

scholarly journals Emission estimates and air quality impacts from the use of alternative fuels by the Titan cement factory in Thessaloniki

2013 ◽  
Vol 14 (2) ◽  
pp. 218-224
Keyword(s):  
Alternative Fuels ◽  
Fossil Fuels ◽  
Alternative Fuel ◽  
Cement Industry ◽  
Partial Replacement ◽  
Limit Values ◽  
Cement Factory ◽  
Pollution Levels ◽  
Fuel Substitution ◽  
The Impact

Cement production is an energy-intensive process. Utilisation of fossil fuels is common practice in the cement industry around the world. Alternative fuel substitution rates increase every year. More specifically, 18 % of the fuel used by the European cement industry in 2006 consists of alternative fuels. This study aims to investigate the prospects for the partial replacement of conventional fossil fuels currently used in the TITAN cement factory in Thessaloniki, Greece, with alternative fuels, focusing on the impact of alternative fuel use on the emissions of air pollutants from co-incineration operations. Air emissions were estimated for both the conventional fuel and mixtures of conventional fuel with alternative fuels, based on emission factors found in the literature but also using the measurements conducted by TITAN in 2010. Emission estimates indicate that legislative limit values for all pollutants are not exceeded. Based on the emission estimates and measurements in the flue gas, the dispersion of the plume around the factory has been described with an appropriate numerical simulation model. Results suggest that the factory’s contribution to the air pollution levels in the surrounding area is very low for most regulated pollutants.

scholarly journals Effects of Separated Fractions of Fbc Bottom Ash on Selected Properties of Cement Mortars

2020 ◽  
Vol 30 (4) ◽  
pp. 1-20
Author(s):  
Zbigniew Kledyński ◽  
Łukasz Krysiak
Keyword(s):  
Power Plants ◽  
Activity Index ◽  
Bottom Ash ◽  
High Water ◽  
Coarse Grained ◽  
Partial Replacement ◽  
Fine Grained ◽  
Cement Mortars ◽  
Inert Additive ◽  
High Silica

Abstract This paper discusses the effects of partial replacement of cement with fluidized bed bottom ash on the properties of mortars. The analyzed ash samples originating from four Polish power plants were separated by grain size selection into fine and coarse-grained fractions. This process leads to a creation of derivative samples of differing physical properties and, partially, phase compositions, as tested in XRD and TG analyses. Despite its high water demand, the obtained fine-grained fraction has the potential for application in cementbased composites as a reactive, pozzolanic additive. An acceptable activity index may be reached when the sulfate content is limited, implying benefits of combining the ash with low gypsum cements. The coarse-grained fraction is significantly less reactive, while a high silica and aluminate content is related to improved mechanical properties of the composite. It can, therefore, potentially be used as a quasi-inert additive or a substitute for sand.

scholarly journals Performance and Emissions of a Spark Ignition Engine Operated with Gasoline Supplemented with Pyrogasoline and Ethanol

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4671
Author(s):  
Luís Durão ◽  
Joaquim Costa ◽  
Tiago Arantes ◽  
F. P. Brito ◽  
Jorge Martins ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
Agricultural Land ◽  
Synergistic Effects ◽  
Engine Performance ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Ternary Mixtures ◽  
Partial Replacement ◽  
Chemical Compositions ◽  
Waste Biomass

The partial replacement of fossil fuels by biofuels contributes to a reduction of CO2 emissions, alleviating the greenhouse effect and climate changes. Furthermore, fuels produced from waste biomass materials have no impact on agricultural land use and reduce deposition of such wastes in landfills. In this paper we evaluate the addition of pyrolysis biogasoline (pyrogasoline) as an additive for fossil gasoline. Pyrogasoline was produced from used cooking oils unfit to produce biodiesel. This study was based on a set of engine tests using binary and ternary mixtures of gasoline with 0, 2.5, and 5% pyrogasoline and ethanol. The use of ternary blends of gasoline and two different biofuels was tested with the purpose of achieving optimal combustion conditions and lower emissions, taking advantage of synergistic effects due to the different properties and chemical compositions of those biofuels. The tests were performed on a spark-ignition engine, operated at full load (100% throttle, or WOT—wide open throttle) between 2000 and 6000 rpm, while recording engine performance and exhaust gases pollutants data. Binary mixtures with pyrogasoline did not improve or worsen the engine’s performance, but the ternary mixtures (gasoline + pyrogasoline + ethanol) positively improved the engine’s performance with torque gains between 0.8 and 3.1% compared to gasoline. All fuels presented CO and unburned hydrocarbons emissions below those produced by this type of engine operated under normal (fossil) gasoline. On the other hand, NOx emissions from oxygenated fuels had contradictory behaviour compared to gasoline. If we consider the gains achieved by the torque with the ternary mixtures and reductions in polluting emissions obtained by mixtures with pyrogasoline, a future for this fuel can be foreseen as a partial replacement of fossil gasoline.

scholarly journals DETERMINING THE ROLE OF INDIVIDUAL FLY ASH PARTICLES IN INFLUENCING THE VARIATION IN THE OVERALL PHYSICAL, MORPHOLOGICAL, AND CHEMICAL PROPERTIES OF FLY ASH

2016 ◽  
Vol 56 (4) ◽  
pp. 265-282 ◽  
Author(s):  
Usman Haider ◽  
Zdenek Bittnar ◽  
Lubomír Kopecky ◽  
Vít Šmilauer ◽  
Jaroslav Pokorny ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Chemical Properties ◽  
Cementitious Materials ◽  
Individual Particle ◽  
Particle Analysis ◽  
Fly Ashes ◽  
Alumino Silicate ◽  
Individual Particles

The properties of fly ashes vary because of the differences in the properties of their individual particles, and the determination of variation in these properties is of interest to the industries which use pulverized raw fly ash in applications, such as in cementitious materials and in the recovery of certain rare elements from raw fly ash. To investigate the differences in individual particles, four pulverized raw fly ashes from thermal power plants of the Czech Republic were used in this research. It was observed from FE-SEM that all four fly ashes consist of glassy hollow spherical, solid spherical, porous spherical, bright spherical, porous slaggy and compact slaggy particles. Box and whisker diagrams were plotted from the data of EDX individual particle analyses, which showed that the data of percentages for the Si, Al, and Fe elements is more scattered as compared to other elements. It was further observed from ternary phase diagrams and pseudo coloured images, that nature of fly ash particles changes from alumino silicate glassy to alumino silicate calcite metallic to pure ferro-metallic,where glassy particles showed high percentages and pure calcite particles were absent in fly ashes. Furthermore, a comparison between the XRF, the EDX total area analyses, showed that the EDX individual particle analysis gives more realistic and reliable data with median, mean, and the standard deviation for percentages of each element present in the fly ashes.

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