scholarly journals Lightweight masonry block without Portland cement

2021 ◽  
Vol 26 (5) ◽  
pp. 945-953
Author(s):  
Paki Turgut ◽  
Mehmet Can Alas ◽  
Muhammed Arif Gurel
Keyword(s):  
Thermal Conductivity ◽  
Fly Ash ◽  
Portland Cement ◽  
Chemical Properties ◽  
Waste Materials ◽  
Fly Ashes ◽  
Free Lime ◽  
The World ◽  
Belt Conveyors ◽  
Lightweight Masonry Block

ABSTRACT Huge amounts of fly ash - a substance that does not conform to the ASTM C618 classification due to its chemical properties - have been abandoned in landfills around the world, despite their self-cementing property. It has not been used in concrete making applications due to its large amounts of free lime and sulfate contents. The fly ash in these plants is dumped in landfills, causing serious environmental hazards. Fly ash is disposed to the landfills by belt conveyors after being humidified with water. Therefore, the fly ashes humidified in the landfill areas are hydrated in nature. This hydration is further intensified in landfills by rain and snow. Thus, the free lime content of fly ash decreases due to its long hydration process. In this work, the lightweight masonry blocks were produced by mixing normal and hydrated fly ashes or normal, hydrated fly ash and lime without Portland cement. The compressive strength, water absorption, sorptivity, density, porosity, and thermal conductivity values of the samples produced were determined. The results obtained from these tests showed that lightweight masonry blocks could be produced by using these waste materials in building applications.

Technical Note on the Determination of Free Lime (CaO) in Fly Ash

1984 ◽  
Vol 43 ◽  
Author(s):  
Scott Schlorholtz ◽  
Turgut Demirel
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Recent Work ◽  
Technical Note ◽  
Fly Ashes ◽  
Major Drawback ◽  
Free Lime ◽  
Chemical Test ◽  
Lime Content

AbstractMany fly ashes contain free lime (CaO) and periclase (MgO) [1,2]. These two compounds, when present in excessive amounts, are known to cause soundness problems in portland cement [3,4]. Recent work [5] has indicated that the autoclave expansion of portland cement-fly ash pastes is related to the concentration of CaO and MgO in a given paste, free lime typically being more detrimental than periclase. The purpose of this technical note is to briefly discuss two methods that are currently available for determining the free lime content of fly ash, and to suggest a supplement to the autoclave test (described in ASTM C 151). The major drawback of the autoclave test is that it requires approximately two days to complete and therefore it would be helpful to have a quick chemical test that could be used to indicate the soundness properties of a given fly ash.

COMPRESSIVE STRENGTH AND THERMAL CONDUCTIVITY OF WATER AND AIR CURED PORTLAND CEMENT-FLY ASH-SILICA FUME MORTARS

2018 ◽  
Vol 17 (9) ◽  
pp. 2023-2030
Author(s):  
Arnon Chaipanich ◽  
Chalermphan Narattha ◽  
Watcharapong Wongkeo ◽  
Pailyn Thongsanitgarn
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Silica Fume

Low Cement/High Fly Ash Concretes: Their Properties and Response to Chemical Admixtures

1987 ◽  
Vol 113 ◽  
Author(s):  
V. H. Dodson
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Calcium Hydroxide ◽  
Pozzolanic Reaction ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Fly Ashes ◽  
Chemical Admixtures ◽  
Reaction With Water

ABSTRACTIn practice, the amount of fly ash added to portland cement concrete varies depending upon the desired end properties of the concrete. Generally, when a given portland cement concrete is redesigned to include fly ash, between 10 and 50% of the cement is replaced by a volume of fly ash equal to that of the cement. Sometimes as much as twice the volume of the cement replaced, although 45.4 kg (100 lbs) of cement will only produce enough calcium hydroxide during its reaction with water to react with about 9 kg (20 lbs) of a typical fly ash. The combination of large amounts of certain fly ashes with small amounts of portland cement in concrete has been found to produce surprisingly high compressive strengths, which cannot be accounted for by the conventional “pozzolanic reaction”. Ratios of cement to fly ash as high as 1:15 by weight can produce compressive strengths of 20.7 MPa (3,000 psi) at I day and over 41.4 MPa (6,000 psi) at 28 days. Methods of identifying these “hyperactive” fly ashes along with some of the startling results, with and without chemical admixtures are described.

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.

Mechanical Properties of Mortars Prepared by Alkali Activated Fly Ash Coming from Different Production Batches

2015 ◽  
Vol 244 ◽  
pp. 140-145 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Materials ◽  
Chemical Properties ◽  
Raw Material ◽  
Fly Ashes ◽  
Coal Burning ◽  
Alkali Solutions ◽  
One Year ◽  
Alkali Activated

Fly ash is a well utilizable secondary raw material for the production of alkali activated construction materials. It is a significant alumina-silicates source suitable for the chemical reaction resulting in hardened composites. Physical and chemical properties of fly ashes as a co-product of coal burning mainly depend on characteristics of coal, burning temperature and combustion conditions. High variability of the properties of fly ash causes an uncertainty in the properties of alkali activated mortars. Time behaviour of the composition of the fly ash produced in a heating plant located in Košice, Slovakia as well as leaching behaviour of both alumina and silica from particular batches during one-year period was documented. Leaching tests were carried out using the distilled water and alkali solutions with three different concentrations. Both compressive and tensile strengths of alkali activated mortars were measured, and the correlation between the mechanical properties of hardened mortars and the chemical composition of fly ashes as well as their leaching characteristics was investigated.

scholarly journals REVIEW ON WASTE MATERIAL USAGE IN CEMENT CONCRETE MIX

YMER Digital ◽  
2021 ◽  
Vol 20 (12) ◽  
pp. 694-709
Author(s):  
S Mahaboob Subhani ◽  
◽  
P Dinesh Sankar Reddy ◽  
S .Altaf Hussain ◽  
◽  
...  
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Portland Cement ◽  
Calcium Oxide ◽  
Plastic Waste ◽  
Waste Materials ◽  
Cement Concrete ◽  
Sustainable Technologies ◽  
Concrete Mix ◽  
Granite Rocks

Nature has blessed with natural resources like rocks / minerals, vegetation, air and water. These are about one crore eighty six lakhs living creatures existing in the world. Most of the living creatures are using their intellect and residing in the natures nest, where as human being is blessed with unique knowledge and wisdom which propelled to discover wheel, moving machineries and established good shelter with ultra architectural designs. Ancient man was living in huts further more constructed mud houses with the available clay / mud. Over a period of time man discovered calcium oxide to use in construction. In 1840s, a scientist by name William Aspdin has invented the manufacturing process of Portland cement production. Over a period of time, lot of advancements took place in producing different types of cement. During 1950’s fly ash was considered as a waste and used to land fill /dumps. Over a period of time man discovered compatible chemicals in fly ash and successful in mixing Ordinary Portland cement up to 30% which is called Pozzolana Portland cement. Several Researchers tried different waste materials to be used as a potential, concrete mix and have been successful in doing so. This paper deals in reviewing potential waste materials being used in cement concrete. Granite rocks are sliced to fine plates for the utility as flooring material. In the process of cutting and smothering the granite, fine dust of approximately 50µm is generated. Researchers discovered compatibility of granite saw dust in cement mix and were successful. Everyday hundreds and thousands of tones of plastic waste is generated. Researchers also tried to use plastic waste in civil construction and partially successful as plastic is organic in nature where as cement is inorganic in nature, nevertheless plastic waste is found as a potential mix in laying bitumen road. Limestone which consists of calcium atom and oxygen atom exists naturally in certain areas where as calcium oxide is also produced synthetically by cracking calcium carbonate at approximately 1000oC. Researchers have been successful in using calcium oxide, municipal waste in civil construction at different proportions. The optimal quality of final cement is governed by particle size and its distribution. Therefore adequate review is also done in terms of particle size, distribution and quality. The current objective of this review article is to give an insight about the sustainable technologies in cement using waste materials disposed in abundance.

Influence of Physical and Chemical Properties on the Activity of Fly Ashes

1987 ◽  
Vol 113 ◽  
Author(s):  
F. Sybertz
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Hydrochloric Acid ◽  
Potassium Hydroxide ◽  
Chemical Properties ◽  
Experimental Program ◽  
Physical And Chemical Properties ◽  
Fly Ashes ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTIn an experimental program, the suitability of various methods for testing the pozzolanic activity of fly ash was investigated. The research was conducted on virtually all fly ashes approved as concrete additives in Germany. This paper discusses differences in the particle size distribution and the solubility on dissolution with hydrochloric acid and potassium hydroxide of the fly ashes. It also reports on interrelationships between the physical and chemical properties of the fly ashes and the workability and strength of mortars containing fly ash.

Retardation Effects in the Hydration of Cement-Fly Ash Pastes

1984 ◽  
Vol 43 ◽  
Author(s):  
Michael W. Grutzeck ◽  
Wei Fajun ◽  
Della M. Roy
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Solid Phase ◽  
Heat Of Hydration ◽  
Type I ◽  
Fly Ashes ◽  
Solution Composition ◽  
Early Hydration ◽  
High Calcium ◽  
Phase Characterization

AbstractThe hydration of high-calcium and low-calcium fly ash-cementmixtures was investigated to determine the effect of fly ash upon the hydration of a Type I portland cement, and to determine the associated mechanisms of hydration. When blended with portland cement, both fly ashes retarded the early hydration process, the high-Ca more so than the low-Ca. Analyses of solution compositions and calorimetric (heat of hydration) measurements were made. The retardation and hydration effects are discussed in terms of solution composition data and solid phase characterization. The hydration effects were interpreted and compared with the results of previous work.

Fly Ashes Used For Blended Portland Cement: Effect Of Grinding on Cement Quality

1988 ◽  
Vol 136 ◽  
Author(s):  
Erik Stoltenberg-Hansson
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Specific Gravity ◽  
Portland Cement ◽  
Large Scale ◽  
Void Content ◽  
Strength Increase ◽  
Fly Ashes ◽  
Laser Method ◽  
Air Void

ABSTRACTTests have been performed with Class F fly ashes used for the production of interground 20% fly ash cement. Unground and ground fly ashes were mixed with a reference high fineness Portland cement and tested for strength in mortar (ISO/CEN method). The fly ashes were also tested for chemical composition, bulk density and specific gravity, fineness (Blaine) and particle size distribution (laser method). There are considerable variations in the specific weights of the asdelivered fly ashes. It is shown that even a small amount of grinding increases the specific gravity significantly, and improves and homogenizes the particle size distributions, resulting in higher strength. The strength increase corresponds to the decrease in air void content.Intergrinding of fly ash and clinker in large scale mills reduces the power consumption, giving the same 28-day strength as mixed fly ash cement with higher fineness.

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