Development of Structural Concrete with Fly Ash

2014 ◽  
Vol 1054 ◽  
pp. 143-147 ◽  
Author(s):  
Rudolf Hela ◽  
Martin Ťažký
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Power Plants ◽  
Elasticity Modulus ◽  
Partial Replacement ◽  
Past Century ◽  
The Past ◽  
Temperature Combustion ◽  
Pozzolanic Properties ◽  
High Temperature Combustion

The paper describes problems of using fly ash in concrete. Using fly ash produced during high temperature combustion in power plants as addition for concrete has been known since the 60s of the past century. The Standard EN 206 Concrete - Specification, performance, production and conformity characterizes high temperature combustion fly ash as an addition of the type II, i.e. active addition with pozzolanic properties. Use of fly ash as an active addition also enables partial replacement of cement. The paper solves the extent of cement which can be replaced with fly ash in this manner. Influence of addition of fly ash on consistency of concrete, development of compressive strength and elasticity modulus at the age of 7, 28, 60 and 90 days of concrete are observed.

POSSIBILITIES OF DETERMINATION OF OPTIMAL DOSAGE OF POWER PLANT FLY ASH FOR CONCRETE

2016 ◽  
Vol 78 (5-3) ◽  
Author(s):  
Rudolf Hela ◽  
Martin Tazky ◽  
Lenka Bodnarova
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Partial Replacement ◽  
Optimal Dosage ◽  
Test Results ◽  
Temperature Combustion ◽  
High Production ◽  
Positive Effect ◽  
High Temperature Combustion

The paper describes possibilities of making use of high temperature combustion fly ash for production of concrete more effective. Efforts for maximal utilization of high temperature combustion fly ash are supported by high production of fly ash worldwide. Use of high temperature fly ash for concrete has to take into account considerably lower speed of hydration reactions compared to pure Portland cement. The paper states results of experimental determination of optimal dosage of fly ash as partial replacement of cement. Dosage of fly ash for production of concrete was optimized. Test results proved positive effect of dosage of fly ash with respect to granulometry of used cement and fly ash. Taking granulometry of fly ash and cement into consideration improves physico-mechanical properties of concrete compared to concrete with fly ash designed standardly without considering granulometry. 

Use of Fluidized Bed Combustion Fly Ash as Addition Reducing Shrinkage of Concrete

2016 ◽  
Vol 865 ◽  
pp. 141-144 ◽  
Author(s):  
Lucia Osuská ◽  
Rudolf Hela
Keyword(s):  
Composite Material ◽  
High Temperature ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Fresh Concrete ◽  
Fluidized Bed Combustion ◽  
Free Lime ◽  
Natural Properties ◽  
Temperature Combustion ◽  
High Temperature Combustion

Volumetric changes during ageing belong to natural properties of concrete. These changes, either growing or shrinking, can present a problem, which has to be taken into account during design and realization phases. This phenomenon is influenced by various factors and volumetric changes can be eliminated in many ways. One of the possibilities is setting appropriate combination of input materials and use of special additions and admixtures. This paper focused on verification of the method reducing shrinkage of concrete by means of using high temperature combustion fly ash combined with fluidized bed combustion fly ash as addition. The precondition is growth of new forms, in particular primary ettringite and monosulphate, which form because of the content free lime and sulphates in fluidized fly ash. If these minerals are formed in fresh concrete, they can positive prevent shrinkage without destruction of the composite material.

The Radioactivity of 3H in Metals by a High Temperature Furnace and a Liquid Scintillation Counter

2010 ◽  
Author(s):  
Hee Reyoung Kim ◽  
Geun Sik Choi ◽  
Sang Yun Park ◽  
Chang Woo Lee ◽  
Moon Hee Han
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
Liquid Scintillation ◽  
Scintillation Counter ◽  
Liquid Scintillation Counter ◽  
High Temperature Furnace ◽  
Quenching Efficiency ◽  
Temperature Combustion ◽  
High Temperature Combustion ◽  
Temperature Furnace

The radioactivity of 3H of the metal samples from the nuclear sites was analyzed by using a commercialized high temperature furnace and a Liquid Scintillation Counter (LSC). The 3H activity of the sample was measured according to the duration of the high temperature combustion and the oxidation temperature. Basically, the recovery from the furnace was 90% for 3H and the LSC had a quenching efficiency of approximately 30 %. HNO3 was used as a trapping solution for 3H and the solution was cocktailed with a scintillator. The activity extracted from the sample was increased till the combustion time elapsed 60 minutes and the increasing rate was reduced continuously thereafter at 600 °C whereas 80% of radioactivity was extracted during the first 15 minutes at 900 °C. Also, the pretreatment for the metal sample, which included a high temperature combustion and trapping, had the time required of at least four hours at 900 °C. Finally, it was suggested that this high temperature combustion method could be applied to analyze the activity of the radioactive metal waste from the nuclear power plants.

Development of High-Volume High Temperature Fly Ash Concrete (HVFAC)

2015 ◽  
Vol 752-753 ◽  
pp. 544-551 ◽  
Author(s):  
Rudolf Hela ◽  
Lenka Bodnarova
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Portland Cement ◽  
Ecological Impact ◽  
Electric Energy ◽  
High Volume ◽  
Experimental Development ◽  
Fly Ash Concrete ◽  
Temperature Combustion ◽  
Pozzolanic Properties

To ensure sustainable concrete building industry it is necessary to decrease consumption of natural resources for manufacture of concrete and reduce content of CO2 produced during production of cement. This approach has not only ecological impact on future activities but it can also considerably reduce cost of concrete. In the Czech Republic, about 6.5 million tons of high quality fly ash is produced during classic high temperature combustion of anthracite or brown coal for production of electric energy. Fly ash produced in such way has high content of SiO2 and low content of CaO, and it is ranked among co-called siliceous fly ash, which has outstanding pozzolanic properties. This paper describes experience from experimental development of High Volume Fly Ash Concrete (HVFAC), where over 50% of fly ash is used as substitution of Portland cement for binder. High proportion of replaced Portland cement were tested in this research; impacts on strength of concrete at the age of 7 – 180 days, consistency of concrete and other related properties were observed.

scholarly journals Modeling of 210Pb and 210Po radionuclide emissions from local power plants in central Poland

2020 ◽  
Vol 22 (11) ◽  
pp. 2291-2297
Author(s):  
Magdalena Długosz-Lisiecka ◽  
Damian Perka
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
Local Power ◽  
Fine Particulates ◽  
Central Poland ◽  
Activity Concentrations ◽  
Temperature Combustion ◽  
Combustion Processes ◽  
High Temperature Combustion

Due to the more volatile nature of 210Po in relation to 210Pb, an imbalance of activity concentrations in high temperature combustion processes can be observed, especially in fine particulates (diameter < 0.1, 0.2 and 0.5 μm).

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.

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