scholarly journals Influence of Fly Ash From Co-Combustion of Coal and Biomass on Scaling Resistance of Concrete / Wpływ Popiołu Lotnego Ze Współspalania Wegla I Biomasy Na Odpornosc Betonu Na Powierzchniowe Łuszczenie

2010 ◽  
Vol 56 (3) ◽  
pp. 239-254 ◽  
Author(s):  
M. Kosior-Kazberuk ◽  
D. Józwiak-Niedzwiedzka
Keyword(s):  
Fly Ash ◽  
Cost Effective ◽  
Hard Coal ◽  
Freezing And Thawing ◽  
Air Voids ◽  
Freeze Thaw ◽  
Industrial Utilization ◽  
Concrete Production ◽  
Fly Ash Utilization

Abstract Industrial utilization of fly ash from various kinds of fuel plays an important role in the environmentally clean and cost effective power production. The primary market for fly ash utilization is as a pozzolanic addition in concrete production. The paper concerns the concretes containing fly ash called Fly Ash from Biomass (FAB) from co-combustion of hard coal and wood biomass (wood chips). Characterization of the fly ash was carried on by means of X-ray diffractometry and E-SEM/EDS analysis. The results of laboratory studies undertaken to evaluate the influence of FAB on concrete resistance to surface scaling due to cyclic freezing and thawing in the presence of NaCl solution were presented. The tests were carried out for concretes containing up to 25% of fly ash related to cement mass. Additionally, the microstructure of air-voids was described. It was concluded that the FAB has significant effect on concrete freeze/thaw durability. The replacement of cement by fly ash from co-combustion progressively transformed the concrete microstructure into less resistant against freeze/thaw cycles and excessive dosage (over 15%) may dangerously increase the scaling.

Fabrication and Characterization of A356-Basalt Ash-Fly Ash Composites Processed by Stir Casting Method

2017 ◽  
Vol 25 (3) ◽  
pp. 209-214 ◽  
Author(s):  
G. Venkatachalam ◽  
A. Kumaravel
Keyword(s):  
Fly Ash ◽  
Impact Strength ◽  
Hybrid Composites ◽  
Cost Effective ◽  
Weight Fraction ◽  
Stir Casting ◽  
Matrix Composites ◽  
Casting Method ◽  
The Matrix

This paper presents the characterization of A356 composite reinforced with fly ash and basalt ash produced by stir casting method. Aluminium metal matrix composites (AMC) are used in wide variety of applications such as structural, aerospace, marine, automotive etc. Stir casting is cost effective manufacturing process and it is useful to enhance the attractive properties of AMCs. Three sets of hybrid AMC are prepared by varying the weight fraction of the reinforcements (3% basalt + 7% fly ash, 5% basalt + 5% fly, 7% basalt + 3% fly ash). The effect of reinforcements on the mechanical properties of the hybrid composites such as hardness, tensile, compressive and impact strength were studied. The obtained results reveal that tensile, compressive and impact strength was increased when weight fraction of fly ash increased, whereas the hardness increases when weight fraction of the basalt ash increased. Microscopic study reveals the dispersion of the reinforcements in the matrix.

A New Powder Filler, Obtained by Applying a New Technology for Fly Ash Inertisation Procedure

2010 ◽  
Vol 62 ◽  
pp. 27-33 ◽  
Author(s):  
Elza Bontempi ◽  
Annalisa Zacco ◽  
Laura Borgese ◽  
Alessandra Gianoncelli ◽  
Rosario Ardesi ◽  
...  
Keyword(s):  
Fly Ash ◽  
New Technology ◽  
Powder Filler ◽  
Concrete Production ◽  
New Process ◽  
Real Performance ◽  
First Results ◽  
The University ◽  
Primary Materials

In the last years several projects have been developed for treatment of fly ash with the aim of their reuse. A final target of these researches is to evaluate the real performance of the new materials obtained by the treatment and the actual and, if the case, potential markets for the foreseen products. Indeed, the use of a recycled inert would reduce the consumption of natural resources and this is one of the main environmental EU target. Examples are clinkering, road asphaltation and some construction work where specific performances are requested. Moreover, the reuse of inerted fly ash will obtain a reduction of carbon dioxide produced by the necessary treatments of primary materials, as limestone in concrete production. At the University of Brescia (Italy) a new process, based on colloidal silica medium, has been developed to inertise fly ashes, containing heavy metals. This approach appears to be quite promising for industrial application in view of the easiness that can be foreseen in applying it to existing plants treating industrial fly ash. The obtained inert product is a powder, that can be employed as a filler in several application. In this work we present first results about characterization of this new powder material, that can be applied as a filler.

scholarly journals Influence of the fly ash and the prior freezing and thawing on the sulphate resistance of cement mortars

2018 ◽  
Vol 174 ◽  
pp. 02004
Author(s):  
Julia Marczewska
Keyword(s):  
Fly Ash ◽  
Cement Composites ◽  
Sulphate Attack ◽  
Freezing And Thawing ◽  
Natural Conditions ◽  
Air Voids ◽  
Cement Mortars ◽  
Reduction Of Energy Consumption ◽  
Reduction Of Co2 ◽  
By Products

The use of fly ash for the production of cement is a typical example of the utilization of by-products (waste) from various fields of production in construction, a significant reduction of CO2 emissions and reduction of energy consumption. However, in order to be able to determine the suitability of this additive in construction, it is necessary to examine the durability of cement composites with fly ash in various, often complicated, destructive environments. There are known publications regarding the durability of concretes with fly ash in individual environments. However, in natural conditions, several destructive environments are common at the same time. The article presents an attempt to reproduce natural conditions. This paper presents the results of sulphate expansion tests of air-entrained (AE) and non-air-entrained (nAE) Portland and fly ash cement mortars subjected to prior freezing and thawing. Despite significant strains experienced during freeze-thaw cycles, unlike the non-air-entrained Portland cement mortars, the non-air-entrained mortars made of fly ash cement did not exhibit any significant expansion when exposed to Na2SO4. For 17 months no expansion was found in the air-entrained mortars made of either of the cement types when immersed in Na2SO4solution after freezethaw cycles. The results of the SEM and EDS analyses showed that gypsum and ettringite were the sulphate attack products in all the mortars. The highest amounts of ettringite were found in air voids.

scholarly journals Mechanical Characterization of Lightweight Foamed Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Marcin Kozłowski ◽  
Marta Kadela
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Strength ◽  
Waste Utilization ◽  
Sound Insulation ◽  
Strongly Correlated ◽  
Freezing And Thawing ◽  
Acoustic Insulation ◽  
Foamed Concrete

Foamed concrete shows excellent physical characteristics such as low self weight, relatively high strength and superb thermal and acoustic insulation properties. It allows for minimal consumption of aggregate, and by replacement of a part of cement by fly ash, it contributes to the waste utilization principles. For many years, the application of foamed concrete has been limited to backfill of retaining walls, insulation of foundations and roof tiles sound insulation. However, during the last few years, foamed concrete has become a promising material for structural purposes. A series of tests was carried out to examine mechanical properties of foamed concrete mixes without fly ash and with fly ash content. In addition, the influence of 25 cycles of freezing and thawing on the compressive strength was investigated. The apparent density of hardened foamed concrete is strongly correlated with the foam content in the mix. An increase of the density of foamed concrete results in a decrease of flexural strength. For the same densities, the compressive strength obtained for mixes containing fly ash is approximately 20% lower in comparison to the specimens without fly ash. Specimens subjected to 25 freeze-thaw cycles show approximately 15% lower compressive strengths compared to the untreated specimens.

scholarly journals Microstructural Features of Freezing and Thawing-Creep Damages for Concrete Mixed with Fly Ash

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Bing Li ◽  
Lian-ying Zhang ◽  
Ming Li ◽  
Hai Pu ◽  
Chao Ma ◽  
...  
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Ash Content ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Ductile Fractures ◽  
Brittle Fractures ◽  
Morphology Characteristics ◽  
Fracture Features ◽  
Degree Of Fragmentation

The macroscopic morphology characteristics, pore structure characteristics, and microfracture morphology of concrete with fly ash subjected to the freeze-thaw-creep effect were analyzed via scanning electron microscopy (SEM). The results revealed that the macrosection of a specimen subjected to freeze-thaw cycling evolves from a regular to an irregular morphology in which the degree of fragmentation increases. Four specimen pore structure types characterized by single holes, nonconnected hole clusters, connected hole clusters, and fly ash holes, respectively, were identified. The microfracture morphology of the concrete was found to include five types of brittle fractures—river, step, cascade, hemispherical, and irregular patterns—and two types of ductile fractures—dimple and peak forest patterns. Two sets of experiments in which (1) the fly ash content ( m = 35 % ) was kept constant and the number of freeze-thaw cycles increased, and (2) the number of freeze-thaw cycles ( n = 120 ) was kept constant, and the fly ash content was increased were carried out. In both cases, the number of connected hole clusters increased and a surrounding skeleton structure with a needle filamentous or flaky appearance was produced. In addition, the degree of deterioration of the pore structure increased and the fracture features changed from brittle to ductile.

scholarly journals A Simple and Cost-Effective Freeze-Thaw Based Method for Plasmodium DNA Extraction from Dried Blood Spot

2019 ◽  
Author(s):  
Supriya SHARMA ◽  
Riti MANN ◽  
Sandeep KUMAR ◽  
Neelima MISHRA ◽  
Bina SRIVASTAVA ◽  
...  
Keyword(s):  
Dna Extraction ◽  
Dna Isolation ◽  
Cost Effective ◽  
Detection Sensitivity ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Resource Limited ◽  
Cost Effective Method ◽  
The Cost ◽  
Processing Steps

Background: Available DNA isolation methods for Plasmodium involve numerous processing steps, adding to the cost and conferring risk of contamination. Here we devise a simple and cost-effective method for direct extraction of Plasmodium DNA from dried filter paper spot (DBS), appropriate for resource-limited setups. Methods: The protocol involves simple freezing and thawing of DBS, neither involves any purification step nor any chemical reagent. The method was assessed in terms of DNA quantity, PCR detection sensitivity, time requirement, cost effectiveness, labor intensiveness and degree of shearing. The reliability of this method was confirmed by comparing it with other in use methods for Plasmodium DNA isolation. Results: Pure DNA was obtained with this method, as exemplified by the absorbance ratio (260nm /280nm) of 1.2. The protocol produced digestible, PCR-grade genomic DNA, also found to be suitable for sequencing. DNA isolated remained stable and retained its integrity after storage for one month at 4 0C. Conclusion: Our process substantiated as efficient, reproducible, simple, fast, and inexpensive. Development of this optimized freeze-thaw based DNA extraction method for malaria parasite may provide a valuable tool for molecular analysis in resource-limited setups. This is the first report of DNA extraction from DBS of Plasmodium utilizing freeze-thaw.

Characterization of lead-bearing phases in municipal waste combustor fly ash

1996 ◽  
Vol 54 ◽  
pp. 516-517
Author(s):  
L. L. Sutter ◽  
G. R. Dewey ◽  
J. F. Sandell
Keyword(s):  
Fly Ash ◽  
Bottom Ash ◽  
Municipal Waste ◽  
Primary Concern ◽  
Leaching Behavior ◽  
Waste Combustion ◽  
Lead And Cadmium ◽  
Lead Speciation ◽  
Accepted Practice

Municipal waste combustion typically involves both energy recovery as well as volume reduction of municipal solid waste prior to landfilling. However, due to environmental concerns, municipal waste combustion (MWC) has not been a widely accepted practice. A primary concern is the leaching behavior of MWC ash when it is stored in a landfill. The ash consists of a finely divided fly ash fraction (10% by volume) and a coarser bottom ash (90% by volume). Typically, MWC fly ash fails tests used to evaluate leaching behavior due to high amounts of soluble lead and cadmium species. The focus of this study was to identify specific lead bearing phases in MWC fly ash. Detailed information regarding lead speciation is necessary to completely understand the leaching behavior of MWC ash.

Monitoring of Petroleum-Related Environmental Contamination Using Fluorescence Fingerprinting

2006 ◽  
Vol 1 (2) ◽  
Author(s):  
P. Literathy ◽  
M. Quinn
Keyword(s):  
Environmental Contamination ◽  
Statistical Evaluation ◽  
Oil Pollution ◽  
Emission Spectra ◽  
Cost Effective ◽  
Petroleum Products ◽  
Danube River ◽  
Aromatic Components ◽  
Analytical Approaches

Petroleum and its refined products are considered the most complex contaminants frequently impacting the environment in significant quantities. They have heterogeneous chemical composition and alterations occur during environmental weathering. No single analytical method exists to characterize the petroleum-related environmental contamination. For monitoring, the analytical approaches include gravimetric, spectrometric and chromatographic methods having significant differences in their selectivity, sensitivity and cost-effectiveness. Recording fluorescence fingerprints of the cyclohexane extracts of the water, suspended solids, sediment or soil samples and applying appropriate statistical evaluation (e.g. by correlating the concatenated emission spectra of the fingerprints of the samples with arbitrary standards (e.g. petroleum products)), provides a powerful, cost-effective analytical tool for characterization of the type of oil pollution and detecting the most harmful aromatic components of the petroleum contaminated matrix. For monitoring purposes, the level of the contamination can be expressed as the equivalent concentration of an appropriate characteristic standard, based on the fluorescence intensities at the relevant characteristic wavelengths. These procedures are demonstrated in the monitoring of petroleum-related pollution in the water and suspended sediment in the Danube river basin

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