scholarly journals Predicting the Compressive Strength of Portland Cement Concretes with the Addition of Fluidized Bed Combustion Fly Ashes from Bituminous Coal and Lignite

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 753
Author(s):  
Jacek Śliwiński ◽  
Artur Łagosz ◽  
Tomasz Tracz ◽  
Radosław Mróz ◽  
Jan Deja
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Bituminous Coal ◽  
Pozzolanic Reaction ◽  
Fluidized Bed Combustion ◽  
Fly Ashes ◽  
Binder Ratio ◽  
Water Binder Ratio

This paper presents the results of an extensive experimental study on the effect of the addition of two types of fly ash produced during fluidized bed combustion of bituminous coal and lignite, which differ substantially in their chemical and mineral compositions, on the compressive strength of concrete. Concretes with water/binder ratios of 0.65, 0.55 and 0.45 made with CEM I 42.5 R Portland cement and gravel aggregate were tested. The analyzed amounts of fly ash added to the binder were 0, 15% and 30% by weight. Based on the results of compressive strength testing after 28 and 90 days of curing, the relationships with the water/binder ratio and fly ash content in the binder were determined. The fly ashes used were highly active and capable of pozzolanic reaction. The relationships established allow the compressive strength of concretes based on composite cement-fly ash binder to be predicted with sufficient accuracy. The results presented in this study are an important contribution to the knowledge of concretes with combined binders. They have the exploratory value of establishing the dependence of compressive strength at 28 and 90 days on binder composition and water-binder ratio. In addition, they could be used almost directly in practical applications.

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.

Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement

2014 ◽  
Vol 629-630 ◽  
pp. 306-313 ◽  
Author(s):  
Mao Chieh Chi ◽  
Ran Huang ◽  
Te Hsien Wu ◽  
Toun Chun Fou
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Building Materials ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Fluidized Bed Combustion ◽  
Initial Setting Time ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.

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

Materials ◽  
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.

Experimental Study on Workability and Strength of Green High Performance Concrete with High Volume Fly Ash

2013 ◽  
Vol 859 ◽  
pp. 52-55 ◽  
Author(s):  
Yong Qiang Ma
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Ash Content ◽  
Splitting Tensile Strength ◽  
Binder Ratio ◽  
Water Binder Ratio

A great deal of experiments have been carried out in this study to reveal the effect of the water-binder ratio and fly ash content on the workability and strengths of GHPC (green high performance concrete). The workability of GHPC was evaluated by slump and slump flow. The strengths include compressive strength and splitting tensile strength. The results indicate that the increase of water-binder ratio can improve the workability of GHPC, however the strengths of GHPC were decreased with the increase of water-binder ratio. When the fly ash content is lower than 40%, the increase in fly ash content has positive effect on workability of GHPC, while the workability begins to decrease after the fly ash content is more than 40%. The addition of fly ash in GHPC has adverse effect on the strengths, and there is a tendency of decrease in the compressive strength and splitting tensile strength of GHPC with the increase of fly ash content.

Synergistic Effect of High Temperature Fly Ash with Fluidized Bed Combustion Fly Ash in Cement Composites

2016 ◽  
Vol 722 ◽  
pp. 113-118
Author(s):  
Martin Ťažký ◽  
Rudolf Hela
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Fossil Fuels ◽  
Cement Composite ◽  
Pozzolanic Reaction ◽  
Cement Composites ◽  
Fluidized Bed Combustion ◽  
Cement Pastes ◽  
Free Cao

Using high temperature fly ash for his pozzolan properties to cement composite production is known a few years ago. New ways combustion of fossil fuels also creates a new type of fly ash, named fluidized bed combustion fly ash. However, this fly ash has same pozzolan properties as has high temperature fly ash, this type is not using for production of cement composites. Fluidized bed combustion fly ash has highly variable chemical composition but usually it has a higher amount of free CaO together with sulphates. This higher amounts of free CaO after mixing of fluidized bed combustion fly ash with water to some extent becomes an activator for the beginning of the pozzolanic reaction, during which is consumed the extinguished CaO. If there is also present high temperature fly ash in cement composite, it could be accelerated his pozzolanic reaction in the same manner using a fluidized bed combustion fly ash. In this experiment was tested a synergy effect in the use of fluidized bed combustion fly ash with high temperature fly ash as an additive. The experiment was carried out on cement pastes that have been studied in particular the progress of hydration processes, pointing to a possible acceleration of pozzolanic reactions of both types of fly ash.

Effects of high-temperature fly ash and fluidized bed combustion ash on the hydration of Portland cement

2015 ◽  
Vol 78 ◽  
pp. 181-188 ◽  
Author(s):  
Pavel Šiler ◽  
Petr Bayer ◽  
Tomáš Sehnal ◽  
Iva Kolářová ◽  
Tomáš Opravil ◽  
...  
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Fluidized Bed Combustion

Effect of Alkaline Solution to Fly Ash Ratio on Geopolymer Mortar Properties

2017 ◽  
Vol 733 ◽  
pp. 85-88 ◽  
Author(s):  
Amir Fauzi ◽  
Mohd Fadhil Nuruddin ◽  
Ahmad B. Malkawi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Bashar S. Mohammed
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Alkaline Solution ◽  
Similar Pattern ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Pozzolanic Reaction

Geopolymer system is new binding materials in concrete industry that is produced by the alkaline solution and materials rich in aluminosilicate such as fly ash. The effect of the alkaline solution to fly ash ratios of 0.3, 0.4 and 0.5 on mortar geopolymer properties was an issue in this study. The results showed that the higher alkaline solution to fly ash ratio improves the workability and brings a longer setting time, whereas the lower alkaline solution to fly ash ratio gains the significant compressive strength. It was a similar pattern with conventional mortar used ordinary Portland cement, which the compressive strength at 7 days was 85%-90% for 28 days compressive strength, whereas conventional mortar is only 65%-75%. This was due to the higher reactivity in geopolymer system that was faster than the pozzolanic reaction.

scholarly journals EFFECTS OF MIX PROPORTION ON ELECTRICAL RESISTIVITY OF CONCRETE WITH FLY ASH

2017 ◽  
Vol 7 (2) ◽  
pp. 53-65
Author(s):  
Su Wai Hnin ◽  
Pakawat Sancharoen ◽  
Somnuk Tangtermsirikul
Keyword(s):  
Compressive Strength ◽  
Electrical Resistivity ◽  
Fly Ash ◽  
Chloride Penetration ◽  
Mix Proportion ◽  
Binder Ratio ◽  
Saturated Concrete ◽  
Paste Content ◽  
Water Saturated ◽  
Water Binder Ratio

The aim of this paper is to investigate the effects of mix proportion on electrical resistivity of concrete with fly ash. The electrical resistivity of concrete is measured by using four Wenner probes. The varied parameters in this study were water/binder ratio, fly ash content, and paste content. Electrical resistivity of water-saturated concrete at several different ages was studied and compared with compressive strength and rapid chloride penetration. Based on experimental results, a good relationship was obtained between results of compressive strength and rapid chloride penetration with electrical resistivity of concrete. The results of this study can be applied further to predict electrical resistivity of concrete when mix proportions are provided. According to the results, lower water/binder ratio concrete had higher resistivity than those with higher water/binder ratios. When cement was replaced at 40% by fly ash, electrical resistivity increased four times when compared to that of OPC concrete.

An Abrasion Damage of Fly Ash Concretes Previously Subjected to Scaling

2016 ◽  
Vol 258 ◽  
pp. 587-590
Author(s):  
Aneta Nowak-Michta
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Abrasion Resistance ◽  
Air Entrainment ◽  
Binder Ratio ◽  
Abrasion Damage ◽  
Water Binder Ratio ◽  
Class F

Effect of quantity and quality of fly ash and compressive strength of concretes with their addition on abrasion resistance previously subjected to scaling is analyzed in the paper. The abrasion resistance was measured in Böhme test according to EN 1338: 2005. The cement was replaced with 20, 35, and 50% of Class F siliceous fly ash in three categories of losses on ignition A, B and C by mass. The water-binder ratio, the air-entrainment and the workability of mixtures were maintained constant at 0.38, 4,5% and 150 mm respectively.Prior scaling causes a decrease in abrasion resistance of fly ash concretes. In addition, both quantitative and qualitative fly ash parameters and compressive strength have an influence on abrasion damage.

Application of Sulfoaluminate Cement for Solidification/Stabilization of Fly Ash from Municipal Solid Waste Incinerators

2012 ◽  
Vol 178-181 ◽  
pp. 795-798 ◽  
Author(s):  
Qi Na Sun ◽  
Jing Miao Li ◽  
Bao Quan Huo ◽  
Ji Bing Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
High Performance ◽  
Curing Time ◽  
Leaching Toxicity ◽  
Binder Ratio ◽  
Waste Incinerators ◽  
Water Binder Ratio

Sulfoaluminate cement (SAC) was utilized for the solidification/stabilization of fly ash from municipal solid waste (MSW) incinerators. The effects of fly ash amount and water/binder ratio were investigated on compressive strength and heavy metals leaching toxicity of solidified matrices at different curing times. The results showed that prolonged curing time, lower fly ash amount and water/binder ratio enhanced the compressive strength and decreased the leaching concentrations of Zn, Pb and Cu. For 28 days cured matrices with fly ash amount 50% and water/binder ratio 0.30, the compressive strength was 32.6 MPa and the leaching concentrations of Zn, Pb and Cu were 14.73, 0.75 and 0.43 mg/L respectively. The leaching concentrations of Zn, Pb and Cu met the demand of GB 5085.3-2007. SAC is proved to be effective for MSW incinerator fly ash solidification/stabilization and high performance matrices for disposal and reuse may be achieved with further formula optimization.

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