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FLYASH INFLYASH IN
GEOTECHNICALGEOTECHNICAL
ENGINEERINGENGINEERINGByBy
LOHIT LEE PAISLOHIT LEE PAIS
S. J College of Engineering,S. J College of Engineering,
Mysore.Mysore.
INTRODUCTIONINTRODUCTION
FLY ASHFLY ASH
PROBLEMS DUE TO FLY ASHPROBLEMS DUE TO FLY ASH
CHARACTERIZATION OF FLY ASHCHARACTERIZATION OF FLY ASH
PHYSICAL & CHEMICAL PROPERTIESPHYSICAL & CHEMICAL PROPERTIES
ENGINEERING PROPERTIESENGINEERING PROPERTIES
REMEDIAL MEASURES DURING REMEDIAL MEASURES DURING CONSTRUCTIONCONSTRUCTION
GEO ENVIRONMENTAL APPLICATIONSGEO ENVIRONMENTAL APPLICATIONS
CONCLUSION.CONCLUSION.
This presentation includes:This presentation includes:
ENVIRONMENTAL GEO-TECH: ENVIRONMENTAL GEO-TECH: Environmental Geotechnic is a field in Environmental Geotechnic is a field in
which:which:
• InvestigatingInvestigating
• PlanningPlanning
• CharacterisationCharacterisation
• Foreseeing & forecasting Foreseeing & forecasting
• Designing of engineering works to Designing of engineering works to protect the environment. protect the environment.
• Avoiding future environmental Avoiding future environmental problemsproblems.
FLY ASH:FLY ASH: Flyash is a waste product Flyash is a waste product
from thermal power stations. from thermal power stations.
100 million tones of flyash is 100 million tones of flyash is produced as a by-product produced as a by-product annually in India alone.annually in India alone.
The ash generated is The ash generated is disposed off in the vicinity of disposed off in the vicinity of the plants as a waste the plants as a waste material covering several material covering several thousand hectares of land. thousand hectares of land.
S. No Zone Name
FA Generation(million tonnes)
Utilization(million tonnes)
% Utilization
1 Southern 13.5 0.8 6.0
2 Western 16.5 0.8 5.0
3 Central 18.0 2.84 15.8
4 Eastern 10.21 2.94 28.8
5 Northern 15.5 2.3 14.8
Total (All India)
73.71 9.68 13.1
Cenospheres (Hollow Cenospheres (Hollow Spheres) Courtesy of Spheres) Courtesy of CSIRO of AustraliaCSIRO of Australia
Fig: Fly ash particlesFig: Fly ash particles
at 2,000x magnification.at 2,000x magnification.Fig:Fig: Typical ash colors Typical ash colors
PROBLEMS FACED DUE TO FLY ASH:PROBLEMS FACED DUE TO FLY ASH:
Fly ash stored affects the ecology Fly ash stored affects the ecology of the land, water and air in the of the land, water and air in the region. region.
Fly ash causes ailments like Fly ash causes ailments like allergic bronchitis, silicosis, and allergic bronchitis, silicosis, and asthma.asthma.
The World Bank has cautioned The World Bank has cautioned India that by 2015, disposal of fly India that by 2015, disposal of fly ash would require 1000 sq km, in ash would require 1000 sq km, in its report on environmental issues its report on environmental issues in the power sector. in the power sector.
Fly ash contaminates Fly ash contaminates
• surface water surface water
• underground water. underground water.
Affects aquatic life. Affects aquatic life.
Is harmful for plants. Is harmful for plants.
Corrodes exposed metallic structures Corrodes exposed metallic structures in its vicinity. in its vicinity.
Fineness is about 4000-8000 cmFineness is about 4000-8000 cm22/g. /g.
Fly ash contains traces of heavy Fly ash contains traces of heavy metals.metals.
PROBLEMS FACED DUE TO FLY ASHPROBLEMS FACED DUE TO FLY ASH
CONTINUED….CONTINUED….
Characteristics of fly ash:Characteristics of fly ash:
Chemical composition.Chemical composition.
Specific gravity.Specific gravity.
Grain size distribution.Grain size distribution.
Atterberg limits. Atterberg limits.
Engineering properties.Engineering properties.
CONSTITUENTSCONSTITUENTS PERCENTAGEPERCENTAGE Silica (SioSilica (Sio22))
Alumina (AlAlumina (Al22OO33))
Iron oxide (FeIron oxide (Fe22OO33))
Calcium oxide (CaO)Calcium oxide (CaO)
Magnesium oxide Magnesium oxide (MgO)(MgO)
Sulphur (SOSulphur (SO33))
Loss on IgnitionLoss on Ignition
Surface area (mSurface area (m22/N)/N)
49 - 6749 - 67
16 - 2916 - 29
4 - 104 - 10
1 - 41 - 4
0.2 - 20.2 - 2
0.1 - 20.1 - 2
0.4 - 0.60.4 - 0.6
2300 - 57002300 - 5700
Chemical compositionChemical composition:
Specific Gravity: Specific Gravity: MATERIALMATERIAL SPECIFIC GRAVITYSPECIFIC GRAVITY
Bottom ashBottom ash
Fly ashFly ash
USAUSA
IndiaIndia
Pond ashPond ash
IndiaIndia
UKUK
PolandPoland
SoilsSoils
2.28-2.782.28-2.78
2.03-2.492.03-2.49
1.84-2.671.84-2.67
1.58-2.391.58-2.39
2.10-2.242.10-2.24
1.90-2.311.90-2.31
2.60-2.802.60-2.80
Grain Size DistributionGrain Size DistributionMATERIAL MATERIAL EFFECTIVEFFECTIV
E SIZEE SIZE
DD1010 (mm) (mm)
DD5050
(mm(mm))
UNIFORMIUNIFORMITYTY
COEFFICICOEFFICIENTENT
COEFFICICOEFFICIENT OFENT OF
CURVATUCURVATURERE
Fly ash Fly ash 0.0027-0.0027-0.020.02
0.036-0.036-0.20.2
13.3-13.3-10.010.0
2.16-2.16-0.730.73
Pond ashPond ash 0.014-0.014-0.0380.038
0.1-0.20.1-0.2 7.1-5.37.1-5.3 1.20-1.20-0.950.95
Bottom Bottom ashash
0.08-0.70.08-0.7 0.46-6.40.46-6.4 5.8-9.15.8-9.1 0.83-0.83-1.031.03
Liquid LimitLiquid Limit Liquid limit is determined by Liquid limit is determined by
cone penetration method. cone penetration method.
As per the Unified As per the Unified Classification system, fly ash Classification system, fly ash will fit into ML group.will fit into ML group.
It is non-plastic in nature.It is non-plastic in nature.
ENGINEERING PROPERTIES:ENGINEERING PROPERTIES:
• Permeability characteristicsPermeability characteristics
• Consolidation and Consolidation and compressibility compressibility characteristicscharacteristics
• Strength characteristics. Strength characteristics.
Shear strength parametersShear strength parameters
California Bearing RatioCalifornia Bearing Ratio
Permeability characteristicsPermeability characteristics
Important in designing the liner to Important in designing the liner to contain leachate migration, dyke to contain leachate migration, dyke to prevent the loss of water as well as for the prevent the loss of water as well as for the stability of slopesstability of slopes..
Fig. 1 Variation of co-efficient of permeability with pressure
ccVV: 0.57 to 1.14cm: 0.57 to 1.14cm22/min. /min. dd: 0.75 to 1.3 g/cm: 0.75 to 1.3 g/cm33..
Consolidation and compressibility Consolidation and compressibility characteristicscharacteristics
Values of compression index for ashesValues of compression index for ashes
PLACEMPLACEMENT ENT VOIDVOID
RATIO.RATIO.
PLACEMENT PLACEMENT CONDITION.CONDITION.
CCCC COMMENTS.COMMENTS.
0.3-1.00.3-1.0
1.0-2.01.0-2.0
2.0-3.02.0-3.0
Conditioned Conditioned compactedcompacted
Hydraulically Hydraulically placed inplaced in
Lagoons.Lagoons.
Lagoon ashes Lagoon ashes to loose to loose
Dumps.Dumps.
0.19-0.19-0.240.24
0.24-0.24-0.610.61
0.61-0.61-0.880.88
Very dense to Very dense to medium dense.medium dense.
Medium dense Medium dense to loose.to loose.
Loose to very Loose to very loose.loose.
Shear strength parametersShear strength parameters
The friction angle: 27The friction angle: 270 0 to to 353500
CBR value varies from 6.8 to 13.5% CBR value varies from 6.8 to 13.5% for soaked condition and from 10.8-for soaked condition and from 10.8-15.4% for unsoaked condition as 15.4% for unsoaked condition as reported in literature.reported in literature.
Bottom ash show higher CBR values Bottom ash show higher CBR values & the CBR value of pond ash is & the CBR value of pond ash is almost in the range for bottom ash. almost in the range for bottom ash.
CBR value of pond ash increase CBR value of pond ash increase from 22% to 45.3% upon addition of from 22% to 45.3% upon addition of 33% of mooram33% of mooram..
California Bearing California Bearing RatioRatio
REMEDIAL MEASURES DURING CONSTRUCTION
Erosion and dust control • wetting down exposed surfaces • stabilized with lime or bitumen • topsoil and vegetation • sealing with bituminous emulsion.
Protection of Underground Pipes and Adjacent Concrete
• the exterior of the pipes coated with tar• pipeswrapped with polyethylene sheeting
Leachate migration
• adequate compaction
• promote surface runoff
• daily proof-rolling Freezing and thawing• controlling upward seepage• avoid using fly ash as a fill
material below the groundwater table
• Geotextile at the base
APPLICATIONS OF FLY ASHAPPLICATIONS OF FLY ASH
Geo-technical applicationsGeo-technical applications
• EmbankmentsEmbankments
• Fills Fills
• Sub base and Sub base and PavementsPavements
• StabilizationStabilization
EmbankmentsEmbankmentsAdvantages: -Advantages: -
Saves topsoil which is otherwise conventionally used.Saves topsoil which is otherwise conventionally used.
Avoids creation of low-lying areas.Avoids creation of low-lying areas.
Avoids expenditure on excavation of soil from one Avoids expenditure on excavation of soil from one place for construction of embankment and filling up of place for construction of embankment and filling up of low-lying areas thus created.low-lying areas thus created.
Does not deprive the nation of the agricultural produce Does not deprive the nation of the agricultural produce that would be grown on the top soil which otherwise that would be grown on the top soil which otherwise would have been used for embankment construction. would have been used for embankment construction.
Reduces the demand of land for disposal/deposition of Reduces the demand of land for disposal/deposition of flyash.flyash.
Uses flyash which otherwise could have been a source Uses flyash which otherwise could have been a source of pollutionof pollution.
Some typical examples of embankments constructed Some typical examples of embankments constructed using fly ash:using fly ash:
Saranath culvert approach embankment, Saranath culvert approach embankment, Varanasi.Varanasi.
New Varuna bridge approach embankment.New Varuna bridge approach embankment.
Delhi metro is using fly ash for landfill and Delhi metro is using fly ash for landfill and embankment construction.embankment construction.
Road embankment at Bhuj and Ramagundum.Road embankment at Bhuj and Ramagundum.
Approach embankment for second Nizamuddin Approach embankment for second Nizamuddin Bridge, New Delhi. Bridge, New Delhi.
7 m high embankment7 m high embankment Operational for 5 Operational for 5 yearsyears No deterioration No deterioration reportedreported
Fly ash exhibiting Fly ash exhibiting better comparison better comparison to soilto soil
OkhlaFlyover
Embankment
Hanuman Setu Embankment at Yamuna Bazar, DelhiHanuman Setu Embankment at Yamuna Bazar, Delhi
3.5 m high, 140m long3.5 m high, 140m long Replication by PWD-Delhi Replication by PWD-Delhi based on Okhla Experiencebased on Okhla Experience
Approach road to NOIDA (Approach road to NOIDA (Second Nizamuddin bridgeSecond Nizamuddin bridge))
Operational for 2 yrsOperational for 2 yrs No deterioration reportedNo deterioration reported
2 Km long, 8m high2 Km long, 8m high approach road approach road embankment constructed using fly embankment constructed using fly ash. ash. 1.5 lakh m1.5 lakh m33 of fly ash is of fly ash is estimated to have been consumed.estimated to have been consumed.
Broad estimates reveal that in the Broad estimates reveal that in the second Nizamuddin approach project, second Nizamuddin approach project, about Rs.1 crore has been saved by about Rs.1 crore has been saved by avoiding expenditure on the use of soil avoiding expenditure on the use of soil and its transport. and its transport.
It is estimated that there is a direct cost It is estimated that there is a direct cost saving of around 30-40% in road saving of around 30-40% in road embankments if fly ash is used instead of embankments if fly ash is used instead of soil. soil.
DVB (DVB (Delhi Vidyut Board )Delhi Vidyut Board ) has saved about has saved about Rs.30 lakh in transportation cost. Rs.30 lakh in transportation cost.
The contribution to environment The contribution to environment protection and agricultural produce is protection and agricultural produce is enormous, if compounded objectively.enormous, if compounded objectively.
StabilizationStabilization
Field construction using soil stabilized with fly ash:Field construction using soil stabilized with fly ash:
Village road to Nandawala, Haryana.Village road to Nandawala, Haryana.
Ghaziabad bye-pass joining SH and NH.Ghaziabad bye-pass joining SH and NH.
A village road section at Panipat, Haryana.A village road section at Panipat, Haryana.
Construction of base coarse for Container Corporation of Construction of base coarse for Container Corporation of India’s container yards at Ludiana, Punjab.India’s container yards at Ludiana, Punjab.
Grout applicationsGrout applications
ULOMAT canal lining at Kakarapar, Gujarath.ULOMAT canal lining at Kakarapar, Gujarath.
Contact grouting of argillaceous problematic fissured Contact grouting of argillaceous problematic fissured foundation rocks of Sardhar Sarovar Dam.foundation rocks of Sardhar Sarovar Dam.
Stabilization of soil using fly ashStabilization of soil using fly ash
FillsFills
• DMRC (Delhi Metro Rail Corporation) has used DMRC (Delhi Metro Rail Corporation) has used fly ash for construction of railway embankments fly ash for construction of railway embankments and land filling. and land filling.
• The DMRC has used The DMRC has used 950 000 cubic metres950 000 cubic metres of of fly ash for filling up land in the Shastri Park in fly ash for filling up land in the Shastri Park in New Delhi. New Delhi.
Sub base and PavementsSub base and Pavements
Fly ash has been used as sub base and Fly ash has been used as sub base and pavements in:pavements in:
• Rural roads near Raichur, Karnataka.Rural roads near Raichur, Karnataka.
• Roads at Delhi, Calcutta, Dadri, Ramgundam Roads at Delhi, Calcutta, Dadri, Ramgundam and Vishakapatnamand Vishakapatnam..
Rural road using Rural road using flyash at Raichurflyash at Raichur
S.NO. NAME OF THE PROJECT
TOTAL QUANTITY OF FLY ASH PROPOSED
1 Km 8.200 to km 29.30 of NH-1 in the State Delhi
1,00,000 cum
2 Haldia Port Connectivity Project -4 laning of NH-41 from km 0 to km 52.7
11,80,000 cum
3 km 470 to km 483.33 & km 0 to km 38 of NH-2 in the state of UP
3,35,000 cum
4 4/6- laning of NH-6 in the state of WB from km 17.60 to km 72.00
32,34,623 cum
5 4/6-laning of NH-6 in the state of WB from km 72 to km 132.45
3,21,300 cum
6 Durgapur Expressway 9,00,000 cum
Total 60,70,923 cum
CONCLUSIONS:CONCLUSIONS:
Fly ash is a by product obtain from Fly ash is a by product obtain from thermal power stations thermal power stations
Fly ash pollutes the ecosystem of Fly ash pollutes the ecosystem of the area drastically.the area drastically.
Fly ash poses a lot of health Fly ash poses a lot of health problems in the area. problems in the area.
The storage of fly ash is problematic The storage of fly ash is problematic and the safe disposal of fly ash is and the safe disposal of fly ash is challenging. challenging.
Remedial measures adopted for the Remedial measures adopted for the safe disposal of fly ash very safe disposal of fly ash very rightly fits in to the area of rightly fits in to the area of sustainable development.sustainable development.
Characterization of fly ash is Characterization of fly ash is required for effective and efficient required for effective and efficient disposal of fly ash in various eco-disposal of fly ash in various eco-friendly applications. friendly applications.
The September 14, 1999 The September 14, 1999 notification issued by MOEF makes notification issued by MOEF makes mandatory use of 25% flyash within mandatory use of 25% flyash within 50 Km radii of thermal power plants 50 Km radii of thermal power plants for manufacture of bricks, tiles etc.for manufacture of bricks, tiles etc.
The quantity of fly ash The quantity of fly ash available is higher than available is higher than that being utilised. that being utilised.
The maximum quantity of The maximum quantity of fly ash can be used in fly ash can be used in geotechnical applicationgeotechnical application
Use of fly ash in various Use of fly ash in various geotechnical applications geotechnical applications in India is gaining in India is gaining momentummomentum..
THANK YOU.THANK YOU.
