USE OF
ELECTRO-FILTERED ASH AND
CLINKER PRODUCED IN THERMOELECTRIC POWER PLANT “NIKOLA
TESLA А and B” AND THERMOELECTRIC POWER PLANT
“КOSTOLAC А and B” FOR THE
NEEDS OF ROAD CONSTRUCTION
research-developing project
EMPLOYER : PUBLIC ENTERPRISE “ROADS OF SERBIA”
PREPARED BY : THE HIGHWAY INSTITUTE
Biljana Vuksanović, B.Sc.(C.E.)
May 2008, Divčibare
• 30-40 million of tons of lignite is used in the Republic of Serbia
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annually
7-8 million of tons of electro-filtered ash is produced
– only 1-2% is used in the cement industry
Electro-filtered ash is disposed at 1400 hectare of fertile land
Estimated value of stockpiled ash is 300 million tons
The greatest producers of energy out of lignite are
Thermo-electric power plant “Nikola Tesla" A and B
Thermo-electric power plant “Kostolac" А and B
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Project goals:
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collection, analysis and synthesis of all previous laboratory data,
laboratory tests for key samples of electro-filtered ash and clinker from the ongoing production of thermo-electric power plants
laboratory tests for samples of ash mixed with lime or cement, in
accordance with our technical standards for road construction materials and
European standards
Comparison of the results and assessment of the quality and applying
possibility of electro-filtered ash and clinker
Analysis of harmful effects of electro-filtered ash and clinker to the
environment
Proposal of possible technical and technological solutions for ash and clinker use in
road construction
economic justification and specification of advantages of electro-filtered ash and
clinker use in construction and maintenance of road beds and superstructures and
other road surfaces in Serbia in comparison to classic road construction materials
(gravel, send, crushed stone etc.).
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PERFORMED TESTS
chemical
physical-chemical
physical
Mineralogical
content of radio-nuclides
pozzolanic attributes
physical-mechanical
For content of heavy metals
For content of other harmful ingredients
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RESULTS AND RECOMMENDATIONS
• Based on physical-mechanical characteristics, chemical
content of ahs and clinker, as well as composites attained
by combining them with lime and cement, performed tests
have undoubtedly shown that these materials are
convenient for road construction.
• The project indicated that placement in road base should be
done in segments isolated from the effects of surface and
underground water, and some characteristic cases have
been treated in this way
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ASH APPLIANCE
Embankments made purely of electro-filtered ash
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embankments with ash
and geotextile
embankments with ash and binders – lime or cement
This type of embankment is more applicable in urban areas, where it is necessary to occupy as less as possible land
during construction. These embankments can be of steeper grad than 1:1.5
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embankments in specific geotechnical conditions
Problems of low bearing capacity of stratum or high level of underground water. These
parameters determine specific conditions for construction of embankments.
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Infilling behind the object
Backfilling of infrastructural elements
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CONSLUSIONS
• Electro-filtered ash and clinker are the most common waste – secondary material in
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the Republic of Serbia
Dumps of electro-filtered ash and clinker, although under constant surveillance and
monitoring, cause significant disturbance of environment:
In the following period primary goal for all relevant institutions in the
Republic of Serbia should be production of electro-filtered ash and clinker
as secondary waste and secondary raw material.
Research-developing project is valorization of waste material, electrofiltered ash and clinker into secondary raw material – road construction
material.
Results and tests show that electro-filtered ash and clinker have changeable mineral,
chemical, physical and mechanical characteristics, which originate from nonhomogeneous composition of coal burnt in thermo-electric power plants.
Electro-filtered ash and clinker have pozzolanic characteristics
Content of radionuclide is bellow the limits of radioactive contamination,
set for construction material;
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• Physical – mechanical characteristics of ash and stabilized ash with
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addition of cement and lime from thermo-electric power plants
“Obrenovac” and “Kostolac” are in the range of values that verify this
material as adequate for construction of roads and other infrastructural
(elements of) systems (embankments, infillings of ditches, infillings
behind objects etc.).
Electro-filtered ash and clinker should be placed in road base in segments,
isolated from the impact of surface and underground waters, since in that way,
during the road exploitation, syringe of chemically harmful elements from ash and
clinker and their penetration into water are disabled.
Completed analysis of expenditures for construction of embankments with
pure electro-filtered ash and ash with 2% of lime at terrain with good and
low bearing capacity, where height of embankment is 3 and 8 m,
compared to the expenditures of construction with common dusty-clayey
and sandy – gritty materials, shows that construction of embankment from
ash per m3, depending on type of embankment, is for 30 – 80% cheaper.
Based on the achieved results of research-developing project, it can be
said that use of electro-filtered ash and clinker in road construction is
possible under the conditions defined in this project.
Results of research-developing project indicate the possibility of ash and
clinker usage in construction of pavement road-base, but additional tests
are needed.
May 09, 2008, Divčibare