coal combustion byproducts (ccbs)igs/ldh/conf/sdp/presentations...12/23/2011 3 bottom ash • fine...

12/23/2011

1

Coal Combustion Byproducts (CCBs):o Characteristics

o Use in Soil Stabilization, Highway Construction, & Road Reclamation

o Impact on Geocomposite Leachate Collection Systems

Dr. Tarunjit Singh Butalia, PEDepartment of Civil and Environmental Engineering

The Ohio State University

ccp.osu.edu

What are Coal Combustion Byproducts (CCBs)?

• CCBs are solid minerals that remain after pulverized coal is burned to generate electricity or steam

• Types:• Fly Ash• Boiler Slag• Bottom Ash• Flue Gas Desulfurization (FGD) Materials

• Dry FGD Materials (FBC, CFBC, SD)• Wet FGD Materials (sulfite & sulfate)

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How are CCBs generated?Flue Gas

Desulfurization (wet/dry)

Coal Boiler

Baghouse/ESP

Economizer

Pulverized Coal Feed

SCR for removing

NOx

BOTTOM ASH BOILER SLAG(dry bottom boilers) (wet bottom boilers)

FLY ASH FGD MATERIALS

Smokestack

Fly Ash• Fine powdery mineral collected by ESP or

baghouse

• Consists mainly of non-combustible matter but also some unburned carbon

• Mostly silt size particles (with some fine sand size particles) which are mostly spherical (and sometimes hollow)

• Types:• Class F (non self-cementing)• Class C (self-cementing)

• Handled dry or wet

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Bottom Ash

• Fine to coarse heavier material collected at dry bottom boilers

• Consists of dark agglomerated ash particles that fall to bottom of boiler

• Sand size particles which are angular

• Handled dry or wet

Boiler Slag

• Crystalline glassy material collected at wet bottom boilers

• Consists of agglomerated ash particles that fall to bottom of boiler

• Crystalline, black, dense, glassy, and hard particles which are angular

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Flue Gas Desulfurization (FGD) Materials

• Solid / semi-solid material obtained from flue gas scrubbers (for SO2 control)

• Predominantly silt size particles

• May be wet or dry as well as sulfite or sulfate depending on the process

• Types:• Dry FGD Materials (FBC, CFBC, SD)• Wet FGD Materials

• Sulfite (Stabilized FGD material)• Sulfate (FGD Gypsum)

StabilizedFGD material

FGDGypsum

CCBs

CCBType

Characteristics TextureAmount

Generated Per Ton of Coal Burnt

(lbs)

Major Constituents

Areas of Major Use

Fly Ash Non-combustible particulate matter carried in stack gases

Powdery, silt like

160 Si, Al, Fe, Ca Cement/Concrete/Grout, Structural Fill, Flowable Fill, Waste Stabilization, Surface Mine Reclamation, Soil Stabilization, Road Base, Mineral Filler, Agriculture

BottomAsh

Material collected in dry bottom boilers, heavier than fly ash

Sand like 40 Si, Al, Fe, Ca Concrete Block, Road Subbase, Snow and Ice Control, Structural Fill, Waste Stabilization, Agriculture, Pipe Bedding, Cement Manufacture

BoilerSlag

Material collected in wet bottom boilers or cyclone units

Glassy angular particles

100 Si, Al, Fe, Ca Blasting Grit, Roofing Granules, Snowand Ice Control, Mineral Filler, Construction Backfill, Water Filtration, Agriculture, Drainage Media

FGDMaterial

Solid/semi-solid material obtained from flue gas scrubbers

Fine to Coarse (Dry or Wet)

700 Ca, S, Si, Fe, Al Wallboard, Road Base/Subbase, Structural Fill, Surface Mine Reclamation, Underground Mine Injection, Livestock Pad, Agricultural Liming Substitute

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Typical CCB Engineering Characteristics

Typical Characteristics Fly AshBottom Ash /

Boiler Slag

FGD Material

Wet Dry

Particle Size (mm) 0.001-0.1 0.1-10.0 0.001-0.05 0.002-0.075

Compressibility (%) 1.8 1.4

Dry Density (lb/ft3) 40-90 40-100 50-110 65-90

Permeability (cm/sec) 10-6-10-4 10-3-10-1 10-6-10-4 10-7-10-6

Shear StrengthCohesion (psi) 0-175 0

Angle of Internal Friction (degree) 25-45 25-45

Unconfined Compressive Strength (psi) 0-1,600 40-2,250

Typical Engineering Properties ofBottom Ash & Boiler Slag

Property Bottom Ash Boiler SlagSpecific Gravity 2.1 - 2.7 2.3 - 2.9Dry Unit Weight 45 - 100 lb/ft3 60 - 90 lb/ft3

Plasticity None NoneAbsorption 0.8 - 2.0% 0.3 - 1.1%

(FHWA-RD-97-148)

Property Bottom Ash Boiler SlagMaximum Dry Density, lb/ft3 75 – 100 82 – 102Optimum Moisture Content, % 12 – 24 8 – 20Los Angeles Abrasion Loss, % 30 - 50 24 – 48Sodium Sulfate Soundness Loss, % 1.5 – 10 1 – 9Friction Angle, degrees 32 – 45 36 – 46California Bearing Ratio, % 40 - 70 40 – 70Permeability Coefficient, cm/sec 10-2 - 10-3 10-2 - 10-3

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Typical Engineering Properties of FGD Materials

Property Stabilized FGD FGD Gypsum(Calcium Sulfite) (Calcium Sulfate)

Particle Sizing (%)Sand Size 1 17Silt Size 90 80Clay Size 9 3Specific Gravity 2.57 2.36

(FHWA-RD-97-148)

Property Stabilized FGDSolids Content, % 55-80Specific Gravity 2.25 – 2.60Dry Density, lb/ft3 75 – 95Friction Angle, degree 35 – 45Permeability, cm/sec 10-6 – 10-7

UCS (28 days), psi 25 - 50

Chemical Composition of Fly Ashesfrom Different Types of Coal

Component Bituminous Coal Subbituminous Coal Lignite CoalSiO2 20-60 40-60 15-45Al2O3 5-35 20-30 10-25Fe2O3 10-40 4-10 4-15CaO 1-12 5-30 15-40MgO 0-5 1-6 3-10SO3 0-4 0-2 0-10Na2O 0-4 0-2 0-6K2O 0-3 0-4 0-4LOI 0-15 0-3 0-5

Expressed as a percent by dry weight

(FHWA-RD-97-148)

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Comparison of Chemical Composition -Class F & Class C Fly Ash

(CBRC, 2003)

Composition of Fly Ash & Cement

(CBRC, 2003)

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Trace Elemental CompositionElement Fly Ash Bottom Ash/Boiler Slag Dry FGD Material (mg/kg) Mechanical ESP/Baghouse

Range Median Range Median Range Median Range Median

Arsenic 3.3-160 25.2 2.3-279 56.7 0.50-168 4.45 44.1-186 86.5

Boron 205-714 258 10-1300 371 41.9-513 161 145-418 318

Barium 52-1152 872 110-5400 991 300-5789 1600 100-300 235

Cadmium 0.40-14.3 4.27 0.10-18.0 1.60 0.1-4.7 0.86 1.7-4.9 2.9

Cobalt 6.22-76.9 48.3 4.90-79.0 35.9 7.1-60.4 24 8.9-45.6 26.7

Chromium 83.3-305 172 3.6-437 136 3.4-350 120 16.9-76.6 43.2

Copper 42.0-326 130 33.0-349 116 3.7-250 68.1 30.8-251 80.8

Fluorine 2.50-83.3 41.8 0.4-320 29.0 2.5-104 50.0 --- ---

Mercury 0.008-3.0 0.073 0.005-2.5 0.10 0.005-4.2 0.023 --- ---

Manganese 123-430 191 24.5-750 250 56.7-769 297 127-207 167

Lead 5.2-101 13.0 3.10-252 66.5 0.4-90.6 7.1 11.3-59.2 36.9

Selenium 0.13-11.8 5.52 0.6-19.0 9.97 0.08-14 0.601 3.6-15.2 10.0

Silver 0.08-4.0 0.70 0.04-8.0 0.501 0.1-0.51 0.20 --- ---

Strontium 396-2430 931 30-3855 775 170-1800 800 308-565 432

Vanadium 100-377 251 11.9-570 248 12.0-377 141 --- ---

Zinc 56.7-215 155 14-2300 210 4.0-798 99.6 108-208 141

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Leachate (TCLP) – Dry FGD and Fly Ash

Chemical Constituent (mg/L)

Dry FGD Fly Ash

pH 9.58-12.01 ---

TDS 11,840-13,790

---

Ag <0.024 0.0-0.05 Al 0.12-0.20 --- As <0.005 0.026-0.4 B 0.543-2.17 0.5-92Ba <0.002 0.30-2.0 Be 0.141-0.348 <0.0001-0.015 Ca 1,380-3,860 --- Cd <0.003 0.0-0.3 Co <0.014-0.026 0.0-0.22Cr <0.005-0.028 0.023-1.4Cu <0.013 0.0-0.43 Fe <0.029 0.0-10.0 Hg <0.0002 0.0-0.003 K 1.3-22.1 ---

Chemical Constituent (mg/L)

Dry FGD Fly Ash

Li 0.04-0.18 --- Mg <0.04-1,360 ---Mn <0.001 0.0-1.9 Mo 0.025-0.088 0.19-0.23 Na 1.32-9.82 --- Ni <0.01 0.0-0.12 P <0.12 ---Pb <0.001-0.017 0.0-0.15 S 132-979 --- Sb <0.24 0.03-0.28 Se <0.001-0.005 0.011-0.869 Si 0.10-0.33 ---Sr 0.83-3.38 ---V <0.019-0.024 --- Zn <0.006 0.045-3.21 Cl- 19.6-67.8 ---

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Leachate (TCLP & SPLP) – FGD Gypsum

Element

FGD Gypsum Limits

SPLP TCLPOhio Non-Toxic Criteria

EPA MCL

As g/mL <0.006 <0.006 0.3 0.01

Ba g/mL 0.101± 0.007 0.37± 0.02 60 2

Cd g/mL 0.002± 0.002 0.0017± 0.0002 0.15 0.005

Cr g/mL 0.0044± 0.0003 0.0059± 0.0003 3 0.1

Cu g/mL <0.001 <0.001 1.3

Hg g/mL 0.0036± 5E-04 0.018± 0.010 0.06 0.002

K g/mL <0.4 2.01± 0.13

Pb g/mL <0.003 <0.003 1.5 0.015

Se g/mL <0.011 0.012± 0.003 1 0.05

Leachate (TCLP, SPLP, Kosson Tier I) –FGD Gypsum

ElementTier I SPLP TCLP

(g/mL) (g/mL) (g/mL)As <0.006 <0.006 <0.006B 0.227 0.130 0.137

Ba 0.161 0.101 0.37Cd 0.0017 0.002 0.0017Cr 0.0056 0.0044 0.0059Cu <0.001 <0.001 <0.001Hg 7.9E-06 3.60E-06 1.8E-05K 0.646 <0.4 2.01Pb <0.003 <0.003 <0.003Se <0.011 <0.011 0.012

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Historical CCB Production & Beneficial Use

(American Coal Ash Association)

2010 CC Production & Beneficial Use

(American Coal Ash Association)

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Each Ton of Fly Ash in Concrete Equals...

Types of Beneficial Uses of CCBs

• Concrete & concrete products

• Cement production

• Structural & flowable fills

• Road base

• Mineral fillers

• Gypsum wallboard

• Soil & waste stabilization

• Snow & ice control

• Blasting grit & roofing granules

• Aggregate

• Agricultural

• Mining

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Some Past OSU Demonstration Projects

• SR 541 Highway Embankment Stabilization (1993)

• SR83 Highway Embankment Stabilization (1994)

• Stabilized FGD Material as Pond Liner (1997)

• Accelerated Loading of Newly Constructed Full-Scale Pavements (2003)

• Full Depth Reclamation of Failing Asphalt Pavements (2006)

State Route 541 Highway Repairs

Before Repair

At the Completion of Construction

Constructed 1993 in Coshocton County, Ohio

• PFBC Ash (Dry FGD) placed in 12 - 16 inch lifts• Total FGD buttress: 100’ L, 40’ W, and 16’ H

Summer 2011

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State Route 83 - Embankment Stabilization

Pavement in 2011

Constructed in 1994 near Cumberland, Ohio

PFBC ash compacted in 12-16 inch lifts

Three test sections constructed

Soil Section (control) FS > 1.0 PFBC/Soil Section FS = 15 PFBC FS = 27

Pavement Before Repairs

Use of Clean Coal Technology By-Products in Construction of Low Permeability Liners

• Constructed at OSU-OARDC Western Branch in South Charleston, Ohio in Summer of 1997

• Holding Capacity of 1 million gallons (6 months storage capacity)

• Primary Liner = 18” Compacted, Stabilized FGD

• Leachate Collection System Current

Filling of Pond with water - 1997During construction

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Model to Predict Resilient Modulus of Lime-Fly Ash Stabilized Soils

Motivation

• Weak and poor subgrade soils need replacement or stabilization

• Use of Class F fly ash (by-product of coal combustion) as a stabilization material

• Quantify the benefits of lime and Class F fly ash stabilization for subgrade soils

• Predict resilient modulus using basic soil properties

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Objectives• Evaluate the Effect of Stabilization Materials (Lime and Fly

ash) on Natural Subgrade Soils

• Measure and Compare the Resilient Modulus of Untreated (Natural) and Lime-Fly ash Stabilized Soils

• Evaluate the Applicability of OSU Model (originally developed for natural soils) to Stabilized Soils

Advantages of LFA Stabilization for Cohesive Soil• Use of in-situ soil and a low-cost by-product material

• Potential reduced pavement thickness by improving subgrade conditions

• Lime and Fly Ash Stabilization• Improves strength• Improves workability• Plasticity and swell reduction• Reduced cost for borrow expensive materials• Expedites construction by improving excessively wet or unstable

subgrade

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Failure Modes for Flexible Pavement

• Total Collapse of Pavement Structure Due to Permanent Displacement Arising in Subgrade Due to Heavy Traffic Load

• Cracking of Pavement Due to Fatigue Caused by Repeated Elastic Strain Reversals in Subgrade (due to nominal loads)

Definition of Resilient Modulus

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Measurement of Mr of Lime and Fly Ash Stabilized Soils

• Few researchers have been measured and implemented Mr for lime stabilized soils:• Fundamental engineering properties for lime stabilized

soils including Mr test (Muhammad, et al. 2000)• Pavement design of lime stabilized subgrade based on

Mr test results (Qubain, et al.2000)• Contribution of lime stabilized subgrade to overall

pavement structure, (Shafee Yusuf, et al. 2001)

• Not much work reported on measurement of Mrfor LFA stabilized soils

Issues with Resilient Modulus Testing

• Complex

• Time Consuming

• Specialized Equipment

• Expertise

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Models for Estimating Mr

Model Author Year

USDA Carmichael and Stuart 1986

Hyperbolic Drumm, et al. 1990

GDOT Santha 1994

TDOT Pezo and Hudson 1994

UCS Lee, et al. 1995

ODOT ODOT 1999

OSU Kim 2003

OSU Model(developed for natural cohesive soils)

2

21

k

a

oct

a

oct

a

r

P

Pk

P

M

• Pa: Atmosphere Pressure,

(Pa =101 kPa)

• σoct: Octahedral Normal Stress,

• τ oct: Octahedral Shear Stress

• σ1 : Major Principal Stress(kPa)

• σd : Deviator Stress (kPa)

• σ3 : Minor Principal Stress or Confining Stress (kPa)

• k1, k2 : Model Constants

2

23

1 3

1

2

9k

dd

aPk

2

21

k

oct

octaPk

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OSU Model (Model Constants)

)()()100

( 765331142 wwwLLaPIaqa

Saak optu

aa

• wopt : Optimum Moisture Content (%)• w : Moisture Content (%)• σ3 : Confining Stress (kPa)• S : Degree of Saturation• qu : Unconfined Compressive Strength (kPa)• PI : Plasticity Index• LL: Liquid Limit

opt

opt

w

wwaaa 12111

LLbPIbqbS

bbk bu

bb8753312

642 )100

(

)(12111 optwwbbb

OSU Model - Inputs

• Optimum moisture content• Moisture content• Dry density• Liquid limit• Plasticity index• Specific gravity• Percent finer than #200 sieve (0.075 mm)• Unconfined compressive strength• Soil stress state (confining stress and deviator stress)

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OSU Model (Sample Range)

Input Parameters Allowable Range

Degree of Saturation (%) 61 ~ 98

Unconfined Compressive Strength (kPa) 80 ~ 700

Plasticity Index (%) 6 ~ 36

Liquid Limit (%) 24 ~ 60

Moisture Content (%) 10 ~ 30

Optimum Moisture Content (%) 12 ~ 25

Model Verification

• Applicability of OSU model developed originally for natural soils to lime-fly ash stabilized soils

• Laboratory experiments conducted on lime fly ash stabilized A-4, A-6, and A-7-6 soils

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Materials for Stabilization

• Fine-grained Soil (A-4, A-6, and A-7-6)• Lime• Fly Ash• Distilled Water

Depth AASHTO USDA Texture

Upper Soil LayerA-4, A-6

Silt Loam, Silty Clay Loam, Loam(0 ~ 15 in.)

Lower Soil LayerA-6, A-7

Silty Clay Loam, Clay,

(15 ~ 60 in.) Clay Loam, Silty Clay

Materials for Stabilization - Soil

• Soil Samples

• FAI-33-537 (A-4)• Location: SR-33 bypass construction site, Lancaster, OH• Intended to be placed on the site as competent subgrade soil

• DEL-Rt23 (A-6)• Location: Near SR-23, Delaware, OH• Determined as unsuitable subgrade and removed from site

• FAI-33-541 (A-7-6)• Location: SR-33 bypass construction site, Lancaster, OH• Determined as unsuitable subgrade and removed from site

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Materials for Stabilization - Lime

• Hydrated lime provided by Carmeuse NA

• Molecular Weight of 74.08

Ingredient % by Weight

Calcium oxide > 68

Magnesium oxide < 4.5

Silica (total) < 2.0

Materials for Stabilization – Fly Ash

• Provided by Gavin Power Plant of AEP

• Class F fly ash

Ingredient% by

WeightIngredient

% by Weight

Silixon Dioxide,

SiO2

46.21Sodium Oxide, Na2O

0.22

Aluminum Oxide, Al2O3

23.15Magnesium

Oxide, MgO

0.65

Iron Oxide, Fe2O3

21.24Potassum

Oxide, K2O2.12

Sum of SiO2, Al2O3

90.6Phosphorus Pentoxide,

P2O5

0.22

Sulfur Trioxide,

SO3

0.42Titanium Dioxide,

TiO2

1.09

Calcium Oxide, CaO

2.7 Fineness23.63

(unitless)

LOI 2.09

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Scope of Laboratory Work

• Basic Tests for Engineering Properties• Atterberg Limits (AASHTO T89-96/AASHTO T 90-96)• Particle Size Analysis (AASHTO T88-97/ ASTM D 442-62)• Specific Gravity (AASHTO T100-95)• Moisture Content (ASTM D 2216-98)• Proctor Compaction (AASHTO T99-97)• Unconfined Compressive Strength (AASHTO T208-96)

• Resilient Modulus (AASHTO T294-94)

Resilient Modulus Test Systemat The Ohio State University

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Modified Triaxial Chamber

Typical Haversine Load Pulse Used in Mr Test

0

20

40

60

80

100

0 1 2 3 4 5

Loa

d (l

bs)

0.037

0.039

0.041

0.043

0.045

0.047

0 1 2 3 4 5Time (second)

LV

DT

(in

)

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Mr Testing SequencesSequence No.

Confining Pressure Deviator Stress Number of load applications

(psi) (psi)

0 6 4 1000

1 6 2 100

2 6 4 100

3 6 6 100

4 6 8 100

5 6 10 100

6 3 2 100

7 3 4 100

8 3 6 100

9 3 8 100

10 3 10 100

11 0 2 100

12 0 4 100

13 0 6 100

14 0 8 100

15 0 10 100

Mixture Proportion & Number of Samples for Each Test and Curing Days

LiquidLimit

PlasticLimit

7 days 7 days 7 days 28 days 60 days 7 days 60 days

Cont 100 % of Soil 4 2 3 3 3 1 1

MIX I 5% Lime, 10% Fly ash 4 2 3 3 3 1 1

MIX II 5% Lime, 15% Fly ash 4 2 3 3 3 1 1

Cont 100 % of Soil 4 2 3 3 3 1 1

MIX I 15% of Fly ash 4 2 3 3 3 1 1


Cont 100 % of Soil 4 2 3 3 3 1 1

MIX I 15% of Fly ash 4 2 3 3 3 1 1


UCS

Number of sample for each test and curing days

Resilient Modulus

DEL-Rt23(A-6)

FAI-33-541(A-7-6)

Mixture ProportionMix NameSoil Name

FAI-33-537(A-4)

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Result of Laboratory Tests -Atterberg Limits

Soil Name Mix NameMixture Content

Mixture Classification

Plastic Limit (%)

Liquid Limit (%)

Plasticity Index (%)

FAI-33-537 (A-4)

Control 100% Soil A-4 15 22 7

MIX I5% Lime 10%

Fly ashA-4 19 22 3

MIX II5% Lime 15%

Fly ashA-4 18 22 4

DEL-Rt23(A-6)

Control 100% Soil A-6 16 28 12

MIX I 15 % Fly ash A-4 15 22 7

MIX II5% Lime 15%

Fly ashA-4 21 25 4

FAI-33-541(A-7-6)

Control 100% Soil A-7-6 18 41 23

MIX I 15 % Fly ash A-4 26 31 5

MIX II5% Lime 15%

Fly ashA-4 24 29 5

Result of Laboratory Tests -Particle Size Analysis & Compaction

Soil NameMix

NameMix

Classification

#4 Sieve Percent Passing

(%)


(%)


(%)


(%)

Maximum Dry Density (kg/m3)

Optimum Moisture

Content (%)

Sample Moisture Content(

%)

FAI-33-537 (A-4)

Control A-4 86 82 65 48 1910.0 11.6 10.6

MIX I A-4 - - - - 1810.0 14.1 12.2

MIX II A-4 - - - - 1800.0 14.2 12.5

DEL-Rt23 (A-6)

Control A-6 98 96 88 74 1885.0 15.4 16.2

MIX I A-4 - - - - 1820.0 14.0 13.8

MIX II A-4 - - - - 1838.0 14.0 13.8

FAI-33-541 (A-7-6)

Control A-7-6 100 99 94 87 1845.0 13.2 15.4

MIX I A-4 - - - - 1840.0 13.2 12.9

MIX II A-4 - - - - 1745.0 15.0 14.8

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Typical Moisture – Density Curve

1650.0

1700.0

1750.0

1800.0

1850.0

1900.0

7 9 11 13 15 17 19

Water Content (%)

Dry

Un

it W

eigh

t (k

g/m

3 )

A-7-6 Cont A-7-6 MIX I (FA:15%) A-7-6 MIX II (L:5%, FA:15%)

Effect of LFA Stabilization on OMC & d

• Generally Class F fly ash does not effect OMC

• Class F fly ash slightly reduces maximum dry density

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Result of Laboratory Tests-Unconfined Compressive Strength

Soil Name Mix Name Curing Time (Days) Average q (kPa)Average Strain

at Peak, (%)

7 days 559.8 3.928 days 542.7 3.660 days 542.8 3.47 days 928.0 1.728 days 999.2 1.560 days 982.8 1.57 days 793.7 1.628 days 893.9 1.560 days 973.1 1.57 days 290.2 12.028 days 283.8 12.060 days 322.0 11.57 days 517.1 2.628 days 496.1 2.660 days 544.7 2.67 days 934.1 1.228 days 1014.4 0.960 days 1048.4 0.87 days 206.4 12.028 days 231.3 12.060 days 221.8 11.07 days 406.4 3.228 days 392.7 3.060 days 401.9 2.57 days 1033.5 1.228 days 1227.9 1.160 days 1314.2 0.9

FAI-33-537(A-4)

DEL-Rt23(A-6)

FAI-33-541(A-7-6)

Control

MIX I

MIX II

Control

MIX I

MIX II

Control

MIX I

MIX II

Effect of LFA Stabilization (Mix Proportion and Curing Time)

0

200

400

600

800

1000

1200

1400

7 17 27 37 47 57 67

Curing Time (Days)

qu (

kPa)

A-7-6 MIX II

A-6 MIX II

A-4 MIX I

A-4 MIX II

A-4 Cont

A-6 MIX I

A-7-6 MIX I

A-6 Cont

A-7-6 Cont

700 kPa (100 psi)

550 kPa (80 psi)

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Result of Laboratory Tests –Resilient Modulus

Soil Name Mix Name Mixture ContentMixture

Classification

Measured Mr (MPa)

7 days 60 days

FAI-33-537 (A-4)

Control 100% Soil A-4 60.98 62.28

MIX I5% Lime 10% Fly

ashA-4 84.08 92.67

MIX II5% Lime 15% Fly

ashA-4 100.57 121.70

DEL-Rt23 (A-6)

Control 100% Soil A-6 48.82 49.26

MIX I 15 % Fly ash A-4 76.70 75.26


ashA-4 103.31 127.08

FAI-33-541 (A-7-6)

Control 100% Soil A-7-6 19.18 19.18

MIX I 15 % Fly ash A-4 63.87 64.45


ashA-4 100.28 121.63

Resilient Modulus(at 3 psi of confining and 6 psi of deviator stress)

7 days, 100.28

7 days, 63.87

7 days, 19.18

7 days, 76.70

7 days, 103.31

7 days, 48.82

7 days, 100.57

7 days, 84.08

7 days, 60.98

60 days, 121.63

60 days, 64.45

60 days, 19.18

60 days, 75.26

60 days, 127.08

60 days, 49.26

60 days, 121.70

60 days, 92.67

60 days, 62.28

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

100% Soil 5% Lime 10%Fly ash

5% Lime 15%Fly ash

100% Soil 15 % Fly ash 5% Lime 15%Fly ash

100% Soil 15 % Fly ash 5% Lime 15%Fly ash

Control MIX I MIX II Control MIX I MIX II Control MIX I MIX II

FAI-33-537 (A-4) DEL-Rt23 (A-6) FAI-33-541 (A-7-6)

Resi

lient M

odulu

s (M

Pa)

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Effect of Lime and Fly ash Stabilization (Control Samples)

0

20

40

60

80

100

120

0 10 20 30 40 50 60 70 80

Deviator Stress (kPa)

Resilie

nt M

odulu

s (

MPa)

(A-4)-Cont Confining Stress : 6 psi (A-4)-Cont Confining Stress : 3 psi (A-4)-Cont Confining Stress : 0 psi

(A-6)-Cont Confining Stress : 6 psi (A-6)-Cont Confining Stress : 3 psi (A-6)-Cont Confining Stress : 0 psi

(A-7-6)-Cont Confining Stress : 6 psi (A-7-6)-Cont Confining Stress : 3 psi (A-7-6)-Cont Confining Stress : 0 psi

Effect of Lime and Fly ash Stabilization (Fly ash Stabilized Samples)

0.000

20.000

40.000

60.000

80.000

100.000

120.000

140.000

0.000 10.000 20.000 30.000 40.000 50.000 60.000 70.000 80.000


Resilie

nt M

odulu

s (

MPa)

(A-6)-MIX I Confining Stress : 6 psi (A-6)-MIX I Confining Stress : 3 psi (A-6)-MIX I Confining Stress : 0 psi

(A-7-6)-MIX I Confining Stress : 6 psi (A-7-6)-MIX I Confining Stress : 3 psi (A-7-6)-MIX I Confining Stress : 0 psi

12/23/2011

32

Effect of Lime and Fly ash Stabilization (Lime-Fly ash Stabilized Samples)

0

20

40

60

80

100

120

140

160

180

0 10 20 30 40 50 60 70 80


Resilie

nt M

odulu

s (

MPa)

(A-4)-MIX II Confining Stress : 6 psi (A-4)-MIX II Confining Stress : 3 psi (A-4)-MIX II Confining Stress : 0 psi

(A-6)-MIX II Confining Stress : 6 psi (A-6)-MIX II Confining Stress : 3 psi (A-6)-MIX II Confining Stress : 0 psi

(A-7-6)-MIX II Confining Stress : 6 psi (A-7-6)-MIX II Confining Stress : 3 psi (A-7-6)-MIX II Confining Stress : 0 psi

Effect of Lime and Fly ash Stabilization

• Reduced liquid limit and plasticity index

• LFA stabilization was most effective for high clay A-6 and A-7-6 soils

• OMC increased and maximum dry unit weight decreased as lime-fly ash was added

• Significant increase in UCS and Mr due to LFA stabilization

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33

Comparison of OSU Model Predicted and

Laboratory Measured Mr (3 psi of confining and 6 psi of deviator stress)

Soil Name Mix NameMixture Content

Mixture Classification

Measured Mr

(MPa)

(Kim)Predicted Mr (MPa)

Percent Error (%)

FAI-33-537 (A-4)

Control 100% Soil A-4 60.98 76.30 25.12

MIX I5% Lime 10%

Fly ashA-4 84.08 109.90 30.70

MIX II5% Lime 15%

Fly ashA-4 100.57 97.24 -3.32

DEL-Rt23 (A-6)

Control 100% Soil A-6 48.82 48.61 -0.44

MIX I 15 % Fly ash A-4 76.70 65.98 -13.97

MIX II5% Lime 15%

Fly ashA-4 103.31 105.40 2.02

FAI-33-541(A-7-6)

Control 100% Soil A-7-6 19.18 46.99 145.07

MIX I 15 % Fly ash A-4 63.87 63.19 -1.05

MIX II5% Lime 15%

Fly ashA-4 100.28 117.36 17.03

OSU Model - Inputs

• Optimum moisture content• Moisture content• Dry density• Liquid limit• Plasticity index• Specific gravity• Percent finer than #200 sieve (0.075 mm)• Unconfined compressive strength• Soil stress state (confining stress and deviator stress)

12/23/2011

34

Conclusions• Increase in UCS and Mr by LFA stabilization

• Class F fly ash is more effective when lime is added

• High clay content A-6 and A-7-6 soils are more effective for LFA stabilization

• LFA stabilization of A-4 soils increased UCS and Mr

• OSU model originally developed for natural soils is applicable to LFA stabilized soils

Additional Work Completed & Recommendations for Future Research

• Evaluate long-term durability of LFA stabilized subgrades• Effect of saturation• Effect of freeze – thaw cycling

• More data collections for A-7-6 soil for OSU model

• OSU model can be specialized for each type of soil (A-4, A-6 and A-7-6)

12/23/2011

35

Accelerated Load Testing of Full Scale Asphalt and Concrete Pavements Constructed of CCPs

Full-Scale Accelerated Testing of CCP Pavement Sections

Motivation

Demonstrate effective use of CCPs (especially fly ash and bottom ash) as alternatives to natural materials currently used in construction and repair of highway pavement wearing surfaces, and bases / subbases

Evaluate the effect of 20+ years of highway traffic on CCP and conventional pavements by accelerated testing of full-scale pavement sections

12/23/2011

36

Benefits of APLF Testing Over In-Service Testing

• Evaluation time period can be significantly reduced • Controlled loading• Comparative performance of pavement types under

similar loading and environmental conditions• Higher benefit to cost ratio• Prediction of pavement life• Provides information for mechanistic design of

pavements

What is APLF ?

• APLF means Accelerated Pavement Loading Facility• Dimension : 80 ft long x 40 ft wide x 18 ft high • Air temperature: 10 to 130 oF• Humidity: 0 to 100%

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37

• Dimension 45 ft long x 38 ft wide x 8 ft deep

• Asphalt and Portland cement concretepavements can be tested

• Moisture can be added to subgrade through pipes on the pit floor

38’

45’

Asphalt Pavement

Concrete Pavement

APLF -Test Pit

APLF – Load Mechanism

• Load Range9,000 lbs to 30,000 lbs

• TiresStandard single and duals

• Test Speed5mph500 repetitions/hr for bidirectional tests

12/23/2011

38

Pavements of interestPavements of interest

Asphalt Concrete (flexible) Pavement

Portland Cement Concrete (rigid) Pavement

Laboratory Testing of Pavement Components

Concrete Slab (Class F Fly ash)Unconfined Compressive Strength Flexural Strength

Freeze-Thaw Resistance Permeability Leaching Potential

Base and Subbase (Class F Fly ash & bottom ash)

Unconfined Compressive Strength PermeabilityLeaching Potential

Subgrade (Class F Fly ash & lime)Index Properties Unconfined Compressive StrengthResilient Modulus

12/23/2011

39

Concrete

• Unconfined Compressive Strength

• Flexural Strength

• Freeze-Thaw Resistance

• Permeability

Class F Fly Ash

Unconfined Compressive Strength

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 28 56 84 112 140 168 196 224 252 280 308 336 364

Curing time (days)

Com

pres

sive

Str

engt

h (p

si)

control

15% FA

30% FA

50% FA

12/23/2011

40

Flexural Strength

0

100

200

300

400

500

600

700

800

Contro

l15

%30

%50

%

Sample ID

Mod

ulu

s of

Ru

ptu

re (

psi

)

28 days of curing

Freeze-Thaw Resistance (ASTM C666)

0.5

0.6

0.7

0.8

0.9

1

0 50 100 150 200 250

Number of Cycles

E/E

o

Control (5.25% air)

15% (5.0% air)

30% (5.25% air)

50% (5.0% air)

60 days of curing

12/23/2011

41

Rapid Chloride Ion Permeability

ASTM C1202

Concrete Mix.

Date CastDate

TestedAge at Test

Total ChargePassed,

(Coulombs)

Chloride IonPermeability

Control 10/15/2002

4/16/2003 6 months 3580 moderate

10/16/2003 1 year 3410 moderate

15 % Fly Ash 10/16/2002

4/16/2003 6 months 1160 low

10/16/2003 1 year 720 very low

30 % Fly Ash 10/16/2002

4/16/2003 6 months 570 very low

10/16/2003 1 year 390 very low

50 % Fly Ash 10/17/2002

4/16/2003 6 months 530 very low

10/16/2003 1 year 300 very low

Leaching Potential

12/23/2011

42

Base and Subbase


• Permeability

Class F Fly Ash and Bottom Ash

Unconfined Compressive Strength& Permeability

12/23/2011

43

Unconfined Compressive Strength& Permeability

Unconfined Compressive Strength vs. Curing Time

0

200

400

600

800

1000

1200

1400

1600

1800

0 20 40 60 80 100 120 140 160 180 200

Curing time (days)

Com

pres

sive

Str

engt

h (p

si)

Mix 11

Mix 12

Mix 14

12/23/2011

44

Subgrade Stabilization

• Index Properties


• Resilient Modulus

Class F Fly Ash & Lime

Basic Soil Properties

Soil Name Mix NameSoil AASHTOClassification

% 0fLime

% ofFlyash

PlasticityIndex(%)

LiquidLimit(%)

MoistureContent

(%)OMC (%)

unit drydensity(kg/m3)

UnconfinedCompressive

Strength(kPa)

Control 0 0 7 22 12.2 11.6 1910.0 559.8

MIX I 5 10 3 22 12.2 14.1 1810.0 928.0

MIX II 5 15 4 22 12.5 14.2 1800.0 793.7

Control 0 0 12 28 16.2 15.4 1885.0 290.2

MIX I 0 15 7 22 13.8 14.0 1820.0 517.1

MIX II 5 15 4 25 13.8 14.0 1838.0 934.1

Control 0 0 23 41 15.4 13.2 1845.0 206.4

MIX I 0 15 5 31 12.9 13.2 1840.0 406.4

MIX II 5 15 5 29 14.8 15.0 1745.0 1033.5

FAI-33-537

DEL-Rt23

FAI-33-541

A-4

A-6

A-7-6

12/23/2011

45

Unconfined Compressive Strength

Soil Name Mix Name Curing Time (Days) Average q (kPa)Average Strain

at Peak, (%)

7 days 559.8 3.928 days 542.7 3.660 days 542.8 3.47 days 928.0 1.728 days 999.2 1.560 days 982.8 1.57 days 793.7 1.628 days 893.9 1.560 days 973.1 1.57 days 290.2 12.028 days 283.8 12.060 days 322.0 11.57 days 517.1 2.628 days 496.1 2.660 days 544.7 2.67 days 934.1 1.228 days 1014.4 0.960 days 1048.4 0.87 days 206.4 12.028 days 231.3 12.060 days 221.8 11.07 days 406.4 3.228 days 392.7 3.060 days 401.9 2.57 days 1033.5 1.228 days 1227.9 1.160 days 1314.2 0.9

FAI-33-537

DEL-Rt23

FAI-33-541

Control

MIX I

MIX II

Control

MIX I

MIX II

Control

MIX I

MIX II

Resilient Modulus7 days 60 days

Control 100% Soil A-4 60.98 62.28

MIX I5% Lime 10%

Fly ashA-4 84.08 92.67

MIX II5% Lime 15%

Fly ashA-4 100.57 121.70

Control 100% Soil A-6 48.82 49.26

MIX I 15 % Fly ash A-4 76.70 75.26

MIX II5% Lime 15%

Fly ashA-4 103.31 127.08

Control 100% Soil A-7-6 19.18 19.18

MIX I 15 % Fly ash A-4 63.87 64.45

MIX II5% Lime 15%

Fly ashA-4 100.28 121.63

FAI-33-537

DEL-Rt23

FAI-33-541

Soil Name Mix NameMixtureContent

AASHTOClassification

Measured Mr (MPa)

Elastic Modulus (psi) Elastic Modulus (Mpa) Subgrade Stiffness

> 13,000 > 90 Good

6,000-13,000 41-90 Fair

< 6,000 < 41 Poor

12/23/2011

46

Proctor Test, Stabilized APLF Subgrade Mix

1.70

1.75

1.80

1.85

1.90

10.0 % 12.0 % 14.0 % 16.0 % 18.0 % 20.0 %

w%

Dry

un

it w

eig

ht

(gm

/cm

3) Unstabilized A-6

Stabilized A-6 (10% FA + 5% L)

Unconfined Compressive Strengthvs. Curing Time

0

50

100

150

200

250

300

0 28 56 84 112 140 168 196

Curing time (days)

Co

mp

ress

ive

Str

eng

th (

psi)

Unstabilized A-6

Stabilized A-6 (10% FA + 5% L)

12/23/2011

47

Design of the Test Pavements Design of the Test Pavements

•• Application: Rural State HighwayApplication: Rural State Highway

•• Average Daily Traffic: 5,000 vehiclesAverage Daily Traffic: 5,000 vehicles

•• Truck Percentage : 6%Truck Percentage : 6%

•• Design Life: 20 yearsDesign Life: 20 years

•• AASHTO 1993 Pavement Design ProcedureAASHTO 1993 Pavement Design Procedure

Full-Scale AcceleratedPavement Testing

12/23/2011

48

Plan View of the test pavements Plan View of the test pavements

B’

A A’

B

Longitudinal profile (ALongitudinal profile (A--A’) of flexible pavement laneA’) of flexible pavement lane

Aggregate (#57 crushed stone)

Unstabilized A-6 Soil

Stabilized A-6 Soil

Aggregate Base Mix 11Mix 12

Mix 14Mix 14Bituminous Base

~34”

18”

24”

6”

6”

Bituminous Base: Ohio DOT specMix 14: 30 #57 + 10 Bottom Ash +15 Fly Ash +5 Cement + 40 Sand

Aggregate Base: Ohio DOT specMix 12: 30 #57 + 20 Bottom Ash + 25 Fly Ash + 5 Cement + 20 SandMix 11: 50 #57 + 20 Bottom Ash + 25 Fly Ash + 5 Cement

Stabilized A-6 Soil: 100 Soil + 10 Fly Ash + 5 Lime

Asphalt Surface 3”

12/23/2011

49

Longitudinal profile (BLongitudinal profile (B--B’) of Rigid Pavement LaneB’) of Rigid Pavement Lane

Aggregate (#57 crushed stone)

Unstabilized A-6 Soil

Stabilized A-6 Soil

Aggregate Base Mix 11Mix 11FA Concrete (50%)FA Concrete (30%)Plain Concrete

15’ 15’ 15’

~34”

18”

24”

8”

6”

Aggregate Base: Ohio DOT specMix 11: 50 #57 + 20 Bottom Ash + 25 Fly Ash + 5 CementStabilized A-6 Soil: 100 Soil + 10 Fly Ash + 5 Lime

Construction Construction ofofPavement Pavement SectionsSections

12/23/2011

50

Compaction of the Drainage Layer Compaction of the Drainage Layer (#(#57 aggregate ~34”) 57 aggregate ~34”)

Compaction of the Compaction of the UnstabilizedUnstabilized subgradesubgrade AA--6 Soil (24”)6 Soil (24”)

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Mixing and placing of the stabilized Mixing and placing of the stabilized subgradesubgrade (18”)(18”)

Compaction of the Compaction of the subbasesubbase for flexible Pavements (mix 12, 6”)for flexible Pavements (mix 12, 6”)

12/23/2011

52

Placing base for flexible Pavements (6”)Placing base for flexible Pavements (6”)

Compaction of AC surface layer for flexible Pavements (3Compaction of AC surface layer for flexible Pavements (3”)”)

12/23/2011

53

Concrete slab for rigid pavements (8”)Concrete slab for rigid pavements (8”)

Finished rigid pavements (8”)Finished rigid pavements (8”)

Control

30% FA

50% FA

12/23/2011

54

Instrumentationand data types

Instrumentation plan of PCC sectionsInstrumentation plan of PCC sections

12/23/2011

55

Instrumentation plan of AC sectionsInstrumentation plan of AC sections

Pressure cell and Pressure cell and tensiometertensiometer

Pressure Cell

Pore Water Pressure Gauge

Wheel path

12/23/2011

56

Embedded Strain Gauges in PCC SectionsEmbedded Strain Gauges in PCC Sections

Pressure Cell

Pore Water Pressure Gauge

Longitudinal StrainGauge

Rossette Strain Gauge

Vibrating Wire Gauge

Wheel path

Accelerated Load Testing• State Route 20-Year Traffic Target is 1 Million ESALs

• Standard dual tires with load of 15,000 lbs• 130,000 number of passes• 1.35 months of APLF testing for bi-directional testing, 8 hrs/day,

5 days/week

• Two Phases:• Phase I: Mechanical loading only (136,000 cycles)• Phase II: Mechanical and environmental (moisture, freeze-

thaw (-12 oC & 54 oC), and elevated temperature 54 oCmaintained) loading:

• Asphalt: Saturation with freeze-thaw for 34,000 cycles. Then 30,000 cycles with elevated temperature.

• Concrete: Saturation with freeze-thaw for 34,000 cycles. Then 10,000 cycles with elevated temperature.

12/23/2011

57

Data Monitoring during Accelerated Pavement Loading

•• Dynamic response monitoring under wheel loading Dynamic response monitoring under wheel loading (monitoring of embedded instrumentation)(monitoring of embedded instrumentation)

•• Falling Weight Deflectometer Testing (FWD)Falling Weight Deflectometer Testing (FWD)

•• Performance data monitoring (rutting and cracking)Performance data monitoring (rutting and cracking)

•• Environmental monitoringEnvironmental monitoring

Falling Weight Falling Weight DeflectometerDeflectometer (FWD) Testing(FWD) Testing

Dynamic Load

CBA

TIME(Time from A to B is Variable, Depending on Drop Height)

25-30msec

12/23/2011

58

Asphalt Pavement Data and Analysis

• Phase I: Mechanical loading only for 136,000 cycles

• Phase II: Saturation with freeze-thaw for 34,000 cycles. Then 30,000 cycles with elevated temperature.

Total Peak Dynamic Deflection vs. Number of Load Repetitions

Aggregate Laye r

Untrea ted Subgrade Soil

Stabilized Subgrade Soil

BaseAC Layer

(Not to Scale )

LVDT1 LVDT2 LVDT3

Subbase

CCP#2 CCP#1 ControlLVDT4 LVDT5 LVDT6 LVDT7 LVDT8 LVDT9

Direction of Travel

LVDT1 LVDT2 LVDT3

LVDT4 LVDT5 LVDT6

LVDT7 LVDT8 LVDT9

0 30000 60000 90000 120000 150000 180000 2100000.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50Phase II

Tot

al D

efle

ctio

n (m

m)

Total Number of Run Repetitions

AC CCP#2 LVDT2 AC CCP#1 LVDT5 AC Control LVDT8

Phase I

12/23/2011

59

Peak Longitudinal Tensile Strains vs. Total Number of Load Repetitions

0 30000 60000 90000 120000 150000 180000 210000-40

-20

0

20

40

60

80

100

120

Lon

gitu

din

al H

ori

zon

tal S

tra

in (

x10

-6)


AC CCP#2 DYN4 AC CCP#1 DYN8 AC Control DYN12

Phase IIPhase I

tensile

compressive

Aggregate Layer

Untreated Subgrade Soil


BaseAC Layer

(Not to Scale)

Subbase

CCP#2 CCP#1 Control

Direction of Travel

DYN1 DYN2 DYN3

DYN5 DYN6 DYN7

DYN9 DYN10 DYN11

DYN1

DYN2

DYN3

DYN4

DYN5

DYN6

DYN7

DYN8

DYN9

DYN10

DYN11

DYN12

DYN4

DYN8

DYN12

Peak Transverse Compressive Strains vs. Total Number of Load Repetitions

0 30000 60000 90000 120000 150000 180000 2100000

-50

-100

-150

-200

-250

Tra

nsve

rse

Ho

rizon

tal S

tra

in (

x10

-6)


AC CCP#2 DYN3 AC CCP#1 DYN7 AC Control DYN11

Phase IIPhase I

Aggregate Layer



BaseAC Layer

(Not to Scale)

Subbase

CCP#2 CCP#1 Control

Direction of Travel

DYN1 DYN2 DYN3

DYN5 DYN6 DYN7

DYN9 DYN10 DYN11

DYN1

DYN2

DYN3

DYN4

DYN5

DYN6

DYN7

DYN8

DYN9

DYN10

DYN11

DYN12

DYN4

DYN8

DYN12

12/23/2011

60

Peak Vertical Stresses on Top of Stabilized and Natural Subgrade vs. Total Number of Load Repetitions

0 30000 60000 90000 120000 150000 180000 2100000

20

40

60

80

100

120

140

Ver

tical

Str

ess

(kP

a)


AC CCP#2 Upper AC CCP#2 Lower AC CCP#1 Upper AC CCP#1 Lower AC Control Upper AC Control Lower

Phase IIPhase I

Aggregate Layer



BaseAC Layer

(Not to Scale)

Subbase

CCP#2 CCP#1 Control

Direction of TravelPC2/PC1 (Upper/Lower) PC4/PC3 (Upper/Lower) PC6/PC5 (Upper/Lower)

PC2

PC1

PC4

PC3

PC6

PC5

Upper

Lower

FWD Tests (Backcalculated Resilient Modulus)

0

5000

10000

15000

20000

25000

30000

0 42500 90000 130000 WaterInfiltration

70000 Restart inNov

Duringsecond

Freeze-thawCycle

End of TestProgram


Mo

du

li o

f B

ase

&S

ub

ba

se L

aye

r (M

Pa

) AC Control

AC CCP#1

AC CCP#2

Phase IOne Design Life

Phase II

12/23/2011

61

Comparison of Rut Development

0

2

4

6

8

10

12

14

16

0 50000 100000 150000 200000 250000


Ru

t D

ep

th (

mm

)

CCP2 CCP1 Control

failure rut depth (Asphalt Institute)

one design life

Phase I

WaterApplication

Temperatureelevated to54 deg. C

Temperaturelowered to20 deg. C

Concrete Pavement Data and Analysis

• Phase I: Mechanical loading only for 136,000 cycles

• Phase II: Saturation and then 34,000 cycles with freeze-thaw. Then 10,000 cycles with elevated temperature.

12/23/2011

62

Peak Longitudinal Strains v. Number of Load Repetitions

ROS14/17ROS15/18

ROS1 ROS7 ROS13Longitudinal Top

Longitudinal BottomTransverse TopTransverse Bottom

ROS4 ROS10 ROS16

ROS3 ROS9 ROS15

ROS6 ROS12 ROS18

ROS Top/Bottom

Aggregate Layer



Base

Concrete Slab

(Not to Scale)

CCP#2 CCP#1 Control

Direction of Travel

ROS1/4

ROS2/5ROS3/6

ROS7/10

ROS8/11ROS9/12

ROS13/16

0 40000 80000 120000 160000 200000 240000 280000-25

-20

-15

-10

-5

0

5

10

15

20

25

160000 170000 180000

Str

ain

(m

icro

stra

in)


PCC CCP#2 Top ROS4 PCC CCP#2 Bottom ROS1 PCC CCP#1 Top ROS10 PCC CCP#1 Bottom ROS7 PCC Control Top ROS16 PCC Control Bottom ROS13

Phase IIPhase I

150000

Peak Transverse Strains v. Number of Load Repetitions

Aggregate Layer



Base

Concrete Slab

(Not to Scale)

CCP#2 CCP#1 Control

Direction of Travel

ROS1/4

ROS2/5ROS3/6

ROS7/10

ROS8/11ROS9/12

ROS13/16

ROS14/17ROS15/18

ROS1 ROS7 ROS13Longitudinal Top

Longitudinal BottomTransverse TopTransverse Bottom

ROS4 ROS10 ROS16ROS3 ROS9 ROS15ROS6 ROS12 ROS18

ROS Top/Bottom

0 40000 80000 120000 160000 200000 240000 280000-30

-20

-10

0

10

20

30

40

50

Str

ain

(m

icro

stra

in)


PCC CCP#2 Top ROS6 PCC CCP#2 Bottom ROS3 PCC CCP#1 Top ROS12 PCC CCP#1 Bottom ROS9 PCC Control Top ROS18 PCC Control Bottom ROS15

Phase IIPhase I

160000 170000 180000150000

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63

Peak Stresses in Subgrade vs. Number of Load Repetitions

Aggregate Layer



Base

Concrete Slab

(Not to Scale)

CCP#2 CCP#1 Control

Direction of TravelPC1 PC2 PC3

PC1 PC2 PC3

0 30000 60000 90000 120000 150000 1800000

20

40

60

80

100

120

140

160

180

200

220

Ver

tica

l Str

ess

es (

kPa

)


PCC CCP#2 PC1 PCC CCP#1 PC2 PCC Control PC3

Phase IIPhase I

peak stresses in AC sections

Fatigue Cracking Analysis Results(Calibrated mechanistic design model of Salsilli et al. 1993)

Control Section

CCP#1(30%FAC)

CCP#2 (50%FAC)

Flexural Strength (MPa) 5.56 5.25 4.97

Tensile Stress (MPa) 0.71 0.37 0.33

Stress Ratio 0.13 0.071 0.068

Allowable Load Repetition (Nf)

5x1034 5x1071 3x1075

12/23/2011

64

Conclusions• Overall, full-scale CCP pavement sections exhibited similar or better

performance than control sections under accelerated traffic loading at as-constructed condition.

• After 20-year equivalent traffic loading, none test pavement sections failed in terms of rutting or fatigue cracking.

• All the three PCC sections demonstrated good performance. Based on the results of the analytical studies, virtually no fatigue damage had occurred in any the three PCC sections by the end of the pavement design life. No fatigue cracking was observed in any of the PCC sections even much later, i.e., at the end of the full-scale testing program.

• Both CCP base/subbase mixes out-performed the control mix based on the collected response, surface rutting, and FWD testing data throughout the whole full-scale testing program.

• During Phase II, the two CCP sections showed better resistance to the adverse environmental conditions and exhibited better performance than the control section. This effect was most manifest at the most intrusive environmental condition at the end of the first freeze-thaw cycle which simulates the high ground water table and thawing condition that is a typical experience for spring in Ohio.

Project Sponsors• Ohio Coal Development Office

• United States Department of Energy’s Combustion Byproducts Recycling Consortium

• Headwaters Resources (formerly ISG Resources)

• American Electric Power

• Carmeuse NA

• American Coal Ash Association

• The Ohio State University

• Ohio University

12/23/2011

65

Full Depth Reclamation of Asphalt Pavements UsingCoal Combustion Byproducts

Asphalt Pavement Rehabilitation

• In recent decades:

• increasing traffic demand (loads & volumes)

• decreasing budgets

• continuing need for a safe, efficient, cost-effective transportation system

• Roads are experiencing serious distress due to economic development, especially with rapid development of suburbs

• Choices:

• Replace distressed road with new one (fewer miles can be paved per year)

• Replace distressed roads by recycling existing pavement and other by-products into a new pavement (more miles can be paved for a given budget)

• Recycling / reclamation of existing pavements must be a priority

12/23/2011

66

Objective

Demonstrate effective use of Class F fly ash in combination with lime or lime kiln dust (LKD) in Full Depth Reclamation of asphalt pavements.

Full Depth Reclamation (FDR)

• FDR is a flexible pavement reclamation process. The full pavement section (wearing surface, base / subbase, and a pre-determined portion of underlying soil) is uniformly pulverized, blended with chemical additives (e.g. cement, fly ash, lime, emulsion) and compacted to construct a new stabilized base. An asphalt overlay can then be placed.

• Short of conventional re-construction, FDR is the only cost-effective pavement rehabilitation procedure that corrects base and subbase problems.

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67

Coal-Fired Fly Ash Generating Power Plants

25 mile radius

Fly Ash

Zimmer power plant in Moscow, Ohio.

Fly ash particles at 2,000x magnification

Typical Fly ash

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68

• Fly ash provides Silica and Alumina needed for cementious reaction with lime to increase strength, stiffness, and durability of stabilized base layer.

• Fly ash act as mineral filler to fill the voids in the granular pulverized pavement mix, thus reducing permeability of the FDR stabilized layer.

Role of Fly Ash in FDR Work

FDR Sites

2006

2006 2007

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69

Section Line Rd. Station LayoutDelaware County

Nine sections were designed and constructed (2006) using the following six mixes:

Station 1: 2% Cement with 7.2 liters per square meter emulsion, 20 cm stabilization depth (0.48 km)

Station 2: 5% Cement, 30 cm stabilization depth (1.3 km)

Station 3: 3% Lime Kiln Dust with 6.3 liters per square meter emulsion, 20 cm stabilization depth (1.1 km)

Station 4: 13 cm Mill and Fill (Two 0.16 km sections at the north and south ends of the project, and a 1.1 km as well as 0.16 km sections near the middle of the project)

Station 5: 5% Lime Kiln Dust with 5% Fly Ash, 20 cm stabilization depth (1 km)

Station 6: 4% Lime with 6% Fly Ash, 20 cm stabilization depth (1.1 km)

Delaware County Pavement Sections(6.6 km)

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Long Spurling Rd. Station LayoutWarren County

↑N

Two sections were designed and constructed (2006):

• Station 1: 13 cm Mill and Fill (0.13 km)

• Station 2: 4% Lime with 6% Fly Ash, 30 cm stabilization depth (0.52 km)

Warren County Pavement Sections (0.65 km)

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Friendly Hills Rd. Station LayoutMuskingum County

Reclaimed 8 feet wide shoulder for 1,000 feet length using Asphalt Zipper reclaimer

5% LKD with 5% Fly Ash, 8 inch stabilization depth (1000 feet)

Conditioned Fly Ash (m/c about 20%) – Glatfelter paper plant (Chillicothe)

2007 Zanesville Shoulder Reclamation:North Pointe Road (1,000 feet)

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Two sections were constructed (2007) using the following mixes:Two sections were constructed (2007) using the following mixes:

5% LKD with 5% Conditioned Fly Ash (Conesville power plant), 8 inch stabilization depth (2.1 mile)5% LKD with 5% Conditioned Fly Ash (Conesville power plant), 8 inch stabilization depth (2.1 mile)

10% Fixated FGD material (Conesville power plant), 8 inch stabilization depth (0.1 mile)10% Fixated FGD material (Conesville power plant), 8 inch stabilization depth (0.1 mile)

Instrumented with pore pressure transducers just below FDR base. Chip and seal completed Instrumented with pore pressure transducers just below FDR base. Chip and seal completed midmid--September 2007September 2007

2007 Zanesville Road Reclamation:Friendly Hills Road (2.2 miles)

Fly Ash Section Fixated FGD Section

FDR Construction

1. Milling of Asphalt Surface (Warren County)

4. Teeth of Mixer (Delaware County)

3. Train of equipment (front to back: water truck, mixer and compactor)

Delaware County

2. Placing of Fly Ash, Lime, & LKD (Warren County)

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FDR Construction (continued)

5. Material before mixing (left) and after mixing

(right), Delaware County

8. Asphalt overlay (Warren County)

7. Final FDR base layer ready for asphalt overlay (Warren County)

6. Compaction of FDR base layer (Delaware County)

Pavement Instrumentation Plan

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Pavement Instrumentation

Pressure Cell

Tensiometer

Shallow LVDT Reference Plate

Asphalt strain gauge

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Falling Weight Deflectometer (FWD) Testingby Ohio DOT

Delaware site before FDR

Measured Deflections - (Delaware County)

0

0.2

0.4

0.6

0.8

1

1.2

0 1 2 3 4 5 6 7

De

fle

cti

on

(m

m)

Location (km from start)

07/06 - Before FDR 10/06 - 3 Weeks after FDR 04/07 - 7 Months

10/07 - 13 Months 07/08 - 22 Months 03/10 - 42 Months

Section 1Cement & Emulsion

Section 2Cement

Section 3LKD & Emulsion

Section 4Control

Section 5LKD & Fly Ash

Section 6Lime & Fly Ash

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Measured Deflections (Warren County)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

De

fle

cti

on

(m

m)

Location (km from start)

07/06 Before FDR

09/06 1 Month after FDR

10/07 14 Months

04/08 20 Months

07/09 35 Months

03/10 43 Months

Section 2Fly Ash & Lime

Section 1Control

•Typical Resilient Modulus values (Mechanistic Empirical Pavement Design Guide 2004, FHWA)

•Outlying data points removed

Average Backcalculated Moduli of FDR Layer from FWD Testing (Delaware County)

0

2000

4000

6000

8000

10000

12000

14000

S1, Cement + Emulsion

S2, Cement S3, LKD + Emulsion S4, Control S5, LKD + fly ash S6, Lime + fly ash

Ela

sti

c M

od

ulu

s o

f b

as

e la

yer

(MP

a)

Section

07/06 - Before FDR

10/06 - 3 Weeks after FDR

04/07 - 7 Months

07/07 - 10 Months

10/07 - 13 Months

04/08 - 19 Months

07/08 - 22 Months

09/08 - 24 Months

04/09 - 31 Months

07/09 - 34 Months

09/09 - 36 Months

03/10 - 42 Months

Open graded cement stabilized aggregate

Soil cement

Lime stabilized soils or unstabilized dense

graded aggregate

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Average Backcalculated Moduli of FDR Layer from FWD Testing (Warren County)

•Typical Resilient Modulus values (Mechanistic Empirical Pavement Design Guide 2004, FHWA)

•Outlying data points were removed

0

2000

4000

6000

8000

10000

12000

14000

S2, fly ash and lime S1, control

Ela

sti

c M

od

ulu

s o

f b

as

e la

yer

(MP

a)

Section

07/06 - Before FDR

09/06 - 3 Weeks after FDR

11/06 - 3 Months

04/07 - 8 Months

07/07 - 11 Months

10/07 - 14 Months

04/08 - 20 Months

07/08 - 23 Months

09/08 - 25 Months

04/09 - 32 Months

07/09 - 35 Months

09/09 - 37 Months

03/10 - 43 Months

Open graded cement stabilized aggregate

Soil cement

Lime stabilized soils or unstabilized dense graded aggregate

Structural Layer CoefficientsDelaware County – Section Line Rd.

Section1 2 3 4 5 6

Cement & Emulsion Cement LKD & Emulsion Mill & Fill LKD & Fly Ash Lime & Fly AshDate MR (psi) ai MR (psi) ai MR (psi) ai MR (psi) ai MR (psi) ai MR (psi) ai

07/0610,173 0.10 5,900 0.08 22,598 0.13 14,174 0.11 9,029 0.09 17,785 0.12

Before FDR10/06

364,033 0.32 755,692 0.41 251,896 0.28 61,306 0.18 477,772 0.35 205,180 0.273 Weeks

04/07276,630 0.29 818,369 0.42 271,244 0.29 36,309 0.15 476,889 0.35 301,933 0.30

7 months07/07

188,288 0.26 922,125 0.44 247,354 0.28 11,559 0.10 810,037 0.42 767,857 0.4110 months

10/07375,183 0.32 886,315 0.43 459,375 0.35 58,785 0.18 948,722 0.44 1,154,670 0.47

13 months04/08

272,050 0.29 937,500 0.44 343,125 0.32 51,809 0.17 699,152 0.40 536,025 0.3719 months

07/08187,438 0.26 935,938 0.44 194,027 0.26 27,529 0.14 517,047 0.36 854,833 0.43

22 months09/08

309,406 0.30 1,232,625 0.48 310,292 0.31 70,803 0.19 834,750 0.42 1,014,972 0.4524 months

04/09134,338 0.23 787,889 0.42 139,903 0.23 53,489 0.17 450,121 0.35 399,004 0.33

31 months07/09

193,025 0.26 1,125,310 0.47 142,004 0.24 205,671 0.27 873,963 0.43 728,000 0.4134 months

09/09370,341 0.32 1,004,056 0.45 117,692 0.22 73,303 0.19 654,627 0.39 1,289,264 0.49

36 months03/10

205,404 0.27 916,072 0.44 132,571 0.23 128,291 0.23 527,431 0.36 525,194 0.3642 months

AASHTO: ai = 0.14*(MR/30,000)1/3

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Structural Layer CoefficientsWarren County - Long Spurling Rd.

Section1 2

Mill & Fill Lime & Fly AshDate MR (psi) ai MR (psi) ai

07/067,408 0.09 3,124 0.07

Before FDR09/06

4,966 0.08 494,545 0.363 Weeks

11/0624,063 0.13 744,513 0.41

3 months04/07

16,725 0.12 223,695 0.278 months AASHTO: ai = 0.14*(MR/30,000)1/3

07/074,827 0.08 564,059 0.37

11 months10/07

6,331 0.08 1,742,470 0.5414 months

04/0827,104 0.14 620,975 0.38

20 months07/08

7,789 0.09 546,037 0.3723 months

09/0817,416 0.12 898,196 0.43

25 months04/09

4,481 0.07 300,907 0.3032 months

07/093,340 0.07 314,653 0.31

35 months09/09

17,203 0.12 390,388 0.3337 months

03/1010,147 0.10 368,157 0.32

43 months

Section 1:Cement + Emulsion

Section 2:Cement

Section 3:LKD + Emulsion

Section 4: Control (Mill & Fill)

Section 5:Fly Ash + LKD

Section 6:Fly Ash + Lime

Delaware Pavements – 2010

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Section 1:Cement + Emulsion

Section 2:Cement

Section 3:LKD + Emulsion

Section 4: Control (Mill & Fill)

Section 5:Fly Ash + LKD

Section 6:Fly Ash + Lime

Delaware Pavements – 2010

Longitudinal Strain Data from Delaware County – 72 km/h

-0.00001

0

0.00001

0.00002

0.00003

0.00004

0.00005

0.00006

0.00007

0.00008

0 850

Lo

ng

itu

din

al S

tra

in

Time (10-2 sec)

Station 1 - Cement & Emulsion

Station 2 - Cement

Station 3 - LKD & Emulsion

Station 4 - Control

Station 5 - LKD & Fly Ash

Station 6 - Lime & Fly Ash

APLF maximum65 microstain

APLF minimum40 microstain

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Transverse Strain Data from Delaware County – 72 km/h

-0.00003

-0.00001

0.00001

0.00003

0.00005

0.00007

0.00009

0 700

Time (10-2

sec)

Tra

ns

vers

e S

trai

nStation 1 - Cement & Emulsion

Station 2 - Cement

Station 3 - LKD & Emulsion

Station 4 - Control

Station 5 - LKD & Fly Ash

Station 6 - Lime & Fly Ash

APLF maximum75 microstrain

APLF minimum 65microstrain

Pressure Cell Data from Delaware County 12/06 – 72 km/h

-5

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35 40 45

Ve

rtic

al S

tre

ss (

kpa

)

Time (10-2 sec)

St. 5 - 5% LKD & 5% Fly Ash

St. 6 - 4% Lime & 6% Fly Ash

Range of stresses from

APLF testing without pavement failure up to

1.5 million ESALs

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81

Conclusions• Pavement sections stabilized with fly ash (+LKD/lime) showed comparable stiffness and strength to the cement stabilized sections for up to 3½ years of monitoring (including three seasons of winter)

• The use of fly ash (with LKD or lime) as substitute for traditional cementitous additives in FDR can result in substantial cost savings as well as additional significant environmental benefits

• Fly ash can be easily mixed and compacted using standard FDR construction equipment

• Longer-term testing data will be available from ongoing pavement performance and environmental condition measurements

Co-Sponsors• Ohio Coal Development Office / Ohio Air Quality Development Authority

• Delaware County Engineer’s Office

• Warren County Engineer's Office

• Muskingum County Engineer’s Office

• Ohio DOT

• Base Construction

• Fly Ash Direct

• Headwater Resources

• Carmeuse NA

• Mintek Resources

• EDP Consultants

• Asphalt Zipper

• Asphalt Recycling and Reclamation Association

• American Coal Ash Association• Midwest Coal Ash Association

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Outreach

• USEPA – C2P2 Case Study 16, Fall 2007• Asphalt Contractor,

February 2007• Roads & Bridges, May

2007

• Better Roads, July 2007

• Ash at Work, August 2007 • ISSMGE Bulletin,

December 2010

Ongoing OSU Research Projects

• Reclamation of Ohio Coal Mine Sites Using FGD Byproducts

• Role of Remining in Mitigating Impacts of Legacy Mining in Ohio

• Stability of Fly Ash During Cyclic Loading

• Effectiveness of Geocomposites as Drainage Layer for CCBs

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The goal of this work is to promote high-volume beneficial use of Ohio FGD by-products inreclamation of abandoned and active Ohio coal surface mine sites. The focus of thisproject is the beneficial use of FGD gypsum and stabilized sulfite FGD material at coalmine sites in the vicinity (within 15 miles) of Ohio FGD generating stations.

Groundwater sampling at MW09-01 at Five Points site

A

A’

B

B’

C C’

9‐02MW10‐01

MW11‐01DMW11‐01S

Groundwater monitoring wells around Five Points site

Reclamation of Ohio Coal Mine SitesUsing FGD Byproducts

Using GIS to Select Abandoned Mine Sites for Reclamation

• Abandoned highwalls and highwall pits digitized using modern aerial photography

• Shapefile added denoting location of the Conesville Coal Power Plant in Coshocton, OH

• 5, 10 and 15 mile buffer zone shapefiles added to select only sites near CCP production

• ODOT highways layer added and clipped to buffers to select for sites within 1 mile of major transportation route

• Highwalls may also be selected based on proximity to schools

• In this example, highwallslocated within 2 miles of schools have been selected

• ODNR’s Division of Mineral Resource Management makes available shapefiles detailing the extent of abandoned underground mines

• Highwalls located directly above abandoned underground mines have been selected

• The National Hydrography Dataset provides GIS layers for stream flow across the United States

• Once clipped to the 15 mile power plant buffer, highwallswere selected that lay within 100 yards of a stream

• US Census Bureau allows users to download “points of interest” within counties

• Extracting data for cemeteries, highwalls were selected that were located within a half mile of a cemetery in the study area

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To advance remining coal in conjunction withreclamation of abandoned mined lands, OSUhas undertaken this research effort whichcouples a preliminary assessment of reminingactivities at Duck Creek Watershed.

• The Duck Creek Watershed was identifiedin the 1974 Land Reborn Study as aPriority 1 watershed in coal bearing region

• Priority 1 – watersheds with significantacid loads that extensively affect streamseither within or downstream fromwatershed

Role of Remining in Mitigating Impacts of Legacy Mining: A Watershed Approach

Current Status(Pre-Law Affected Areas)

Estimated Area (Acres)

Total area of watershed 3,400

Remined/Reclaimed 300

Partially Reclaimed 1,900

Unreclaimed Highwalls and Pits 1,200

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• https://ccp.osu.edu/evaluation_of_liquefaction_potential_of_impounded_fly_ash.pdf

Stability of Fly Ash During Cyclic Loading

Continued laboratory experiments on liquefaction of fly ash from various power plants.

Liquefaction Potential of F.A. Samples

0.00

0.05

0.10

0.15

0.20

0.25

0.30

1 10 100 1000

No. of Cycles to Liquefaction

d

/(2

c)

Predicted CSRs fromSHAKE analysis

Critical points fromSHAKE analysis

85% Compacted with 20 psi effective confining



22 psi effective stress

30 psi effective stress






105% Compacted with 20 psi effective confining 95% comp.

50 psi conf.

95% comp.10 psi conf.

Geosynthetic Clay Liners

• Focus: Study use of GCLs as liners for gypsum monofills

• Objective: Identify effect of gypsum leachate on permeability and swelling of GCL under field conditions

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• Literature: Indicates the presence of cations with lower ionic radii than sodium, as well as liquids with low dielectric constants can increase the hydraulic conductivity of bentonite

• Ruhl and Daniel (1997), showed this effect is case dependent

• Furthermore, in presence of moderate to high confining stresses (overburden pressure) GCL maintained its low permeability



• GCL and gypsum were provided by sponsor. Samples of gypsum leachate liquid were obtained in the Soil Mechanics Laboratory at the Ohio State University (OSU).

• Distilled water through gypsum under a low hydraulic gradient. • The swell potential of the GCL specimens was measured according to

ASTM 4546 using distilled water and gypsum leachate.

• Permeability of the GCL was measured using gypsum leachate water under various confining and low head pressures. Additional baseline tests were conducted under identical confining and head pressures with distilled water permeant. The hydraulic conductivity of GCL specimens was measured at a constant room temperature of about 70ºC using a flexible wall permeameter.

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• Bentomat DN and Bentomat CL DN

• Distilled Water and Gypsum Leachate

• One Dimensional swell tests

• Flexible wall permeameters


Permeability Test Configuration

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88

0

0.1

0.2

0.3

0.4

0.5

0.0001 0.001 0.01 0.1 1 10 100 1000

Time Elapsed (Days)

Sw

ellin

g (

cm)

0

0.04

0.08

0.12

0.16

Gypsum Leachate Distilled water

GCL type: DNVertical pressure: 8 kPa

Sw

ellin

g (

in)

Swell test results for Bentomat DN

68%

23%

14%

0

0.1

0.2

0.3

0.4

0.5

0.0001 0.001 0.01 0.1 1 10 100 1000

Time Elapsed (Days)

Sw

ellin

g (

cm)

0

0.04

0.08

0.12

0.16

Gypsum Leachate Distilled water

GCL type: CL DNVertical pressure: 8 kPa

Sw

ellin

g (

in)

Swell test results for Bentomat CL DN

49%

17%

18%

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1.00E-12

1.00E-10

1.00E-08

1.00E-06

1.00E-04

0 300 600 900 1200 1500 1800

Time (Hr)

k (

cm

/se

c)

Gypsum leachate permeant Distilled water permeant Distilled water permeant (duplicate)

Head pressure less than 70 cm

13.8 kPa increase in head pressure

13.8 kPa increase in head pressure

Permeability of Bentomat DN specimens. Permeants: 1) distilled water 2) gypsum leachate

c 34.5 kPa

1.00E-12

1.00E-10

1.00E-08

1.00E-06

1.00E-04

0 400 800 1200 1600 2000 2400

Time (Hr)

k (

cm/s

ec)

Gypsum Leachate Permeant Distilled Water Permeant

Head pressure less than 70 cm

13.8 kPa pressure applied to influent line

Influent pressure decreased to 7 kPa

Lea

chat

e

Wat

er

Permeability of Bentomat CL DN specimens. Permeants: 1) distilled water 2) gypsum leachate

c 34.5 kPa

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90

1.00E-12

1.00E-10

1.00E-08

1.00E-06

1.00E-04

0 200 400 600 800 1000 1200

Time (Hr)

k (c

m/s

ec)


Head pressure less than 0.7 m

Application of 13.8 kPa pressure to headwater(distilled water)

Application of 13.8 kPa pressure to headwater (leachate)

c kPa

Permeability of Bentomat DN specimens. Permeants: 1) distilled water 2) gypsum leachate

0

0.2

0.4

0.6

0.8

0 200 400 600 800 1000 1200

Time (Hr)

Sw

elli

ng

(c

m)


Application of 13.8 kPa pressure to headwater (leachate)

Application of 13.8 kPa pressure to headwater (distilled water)

Swelling of Bentomat DN specimens. Permeants: 1) distilled water 2) gypsum leachate

c kPa

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1.00E-12

1.00E-10

1.00E-08

1.00E-06

1.00E-04

0 200 400 600 800 1000 1200

Time (Hr)

k (c

m/s

ec)


Head pressure less than 0.7 m

Application of 13.8 kPa pressure to headwater


Dis

tille

d w

ate

r

Leac

hate

c kPa

Permeability of Bentomat CL DN specimens. Permeants: 1) distilled water 2) gypsum leachate

0

0.2

0.4

0.6

0.8

0 200 400 600 800 1000 1200

Time (Hr)

Sw

elli

ng

(c

m)

Gypsum Leachate Permeant Distilled Water Peremant



Dis

tille

d w

ate

r

Leac

hate

Swelling of Bentomat CL DN specimens. Permeants: 1) distilled water 2) gypsum leachate

c kPa

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Past Research: Investigation of various CCP materials using non-woven fabric(Alexis Semach MS Thesis)

Current Research: Study of various CCP materials using woven fabricgeocomposite drainage layer

Effectiveness of Geocompositesas Drainage Layer for CCB Landfills

• Geocomposite leachate collection systems as possible replacements for conventional graded sand filters in CCB landfills

• Geocomposite drainage systems are attractive - not as thick as graded sand filters

• Geocomposite must• not restrict flow of leachate to collection system• prevent migration of CCB material to be retained

through the filter and into leachate collection system

Background

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93

• To evaluate effectiveness of using geocomposites as primary drainage layer for CCB landfills to study potential

• clogging of leachate collection system, and• migration of material into leachate collection

system

Research Objective

Previous Research – Fill

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Previous Research – Fill and Geocomposite

Previous Research – % Solids in Leachate

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95

Previous Research – Fly Ash and Geocomposite

• Measured permeabilities of the CCBs tested ranged from a high value of slightly less than 1x10-4 cm/sec (equivalent to a silt) for FGD gypsum and Class F fly ash samples to 7x10-6 cm/sec (silt or clay) for stabilized FGD.

• When CCB materials were underlain by the geocomposite, effective permeability decreased, typically by a factor of 5.

• Quantity of material recovered in leachate was a small amount that decreased after only one or two pore volumes for FGD gypsum and stabilized FGD.

• Quantity of fly ash recovered in leachate increased during tests until it was more than system could accommodate and testing had to be terminated.

• Fly ash appears to not be adequately retained by sample non-woven geocomposite. Even though initial permeabilities of fly ash and FGD gypsum were similar, the fly ash particles went into the leachate at a much higher rate than did FGD gypsum. The quantity of fly ash increased until laboratory tests on fly ash/geocomposite samples had to be terminated.

Previous Research – Laboratory Testing Summary

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96

• Laboratory Experiments• Permeability of CCB fill material with & without geocomposite• Percent solids in leachate of CCB fill with & without geocomposite

• Field Testing• Permeability and leachate quality of as installed CCB fills with

geocomposite

Current Research

Focus: Study of Fly Ash (silo and ponded), FGD gypsum, and stabilized FGD material underlain by non-woven fabric geocomposite system

• Geocomposite with top woven geotextile layer

• CCB Materials Class F Fly Ash (silo and ponded) FGD Gypsum Stabilized FGD (sulfite) material

• Tests conducted Falling head permeability tests on CCB fill

materials only (porous stone at top and bottom of sample)

Falling head permeability tests on drainage system (bottom porous stone replaced by geocomposite)

• Test results Permeability and percent solids in leachate

as a function of pore volume

Laboratory Testing

Sample

Geotextile Fabric

Geo-GridGeotextile FabricPVC Layer

Hole in PVC for Drainage

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97

Sample

Geotextile FabricGeo-GridGeotextile FabricPVC Layer


CCB Fill and Geocomposite Test System

Silo Fly Ash M

1.00E‐05

1.00E‐04

1.00E‐03

1.00E‐02

0 2 4 6 8

Hydraulic Conductivity (cm/s)

Pore Volume Fraction

porous stone (dry density=79.97pcf)

geocomposite (dry density=83.16pcf)

0

2

4

6

8

10

12

0 2 4 6 8

Percent Solid

s (%

)




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Ponded Fly Ash C

1.00E‐05

1.00E‐04

1.00E‐03

1.00E‐02

0 2 4 6 8

Hyd

raulic Conductivity (cm/s)




0

2

4

6

8

10

12

0 2 4 6 8

Percent Solids (%

)




FGD Gypsum M

1.00E‐05

1.00E‐04

1.00E‐03

1.00E‐02

0 2 4 6 8





0

2

4

6

8

10

12

0 1 2 3 4 5 6 7

Percent Solids (%

)




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FGD Gypsum C

1.00E‐05

1.00E‐04

1.00E‐03

1.00E‐02

0 2 4 6 8

Hyd

raulic Conductivity (cm/s)




0

2

4

6

8

10

12

0 2 4 6 8Percent Solids (%

)Pore Volume Fraction



Sample

Top Geotextile FabricGeo-GridBottom Geotextile FabricPVC Layer


Post-test Geocomposite Inspection

Top of “top geotextile fabric” Top of “geo-grid”Bottom of “top geotextile” fabricTop of “top geotextile fabric”

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Field Test Site

Olentangy River Wetlands Research Park at OSU Campus

Typicalfieldbasin

CCP

CCP

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Plan Viewof FieldTestBasins

Field Construction

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Field Construction

Field Testing

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• Constant Head Test• Water level in each basin

at small intervals was nearly constant and the water level at outflow was controlled at the level of the geocomposite

• Height of water within the trough (h) was measured at specific time intervals during testing gave flow rate

Field Permeability

Silo Fly Ash M

1.00E‐05

1.00E‐04

1.00E‐03

1.00E‐02

0 2 4 6 8





Laboratory Measured Permeability

Field Basin Permeability = 4 x 10-4 cm/sec

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Ponded Fly Ash C

1.00E‐05

1.00E‐04

1.00E‐03

1.00E‐02

0 2 4 6 8







FGD Gypsum M

1.00E‐05

1.00E‐04

1.00E‐03

1.00E‐02

0 2 4 6 8







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• Laboratory testing to date indicates that the new geocomposite non-woven fabric:• retains fly ash and other CCB fill particles

• does not restrict the flow of leachate to collection system

• prevents migration of CCB material into leachate collection system

• Field test basin verification of laboratory results is in progress

Current Research – Preliminary Conclusions

Coal Combustion Products Extension Program:Education & Outreach

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Feeding and Hay Storage PadsFeeding and hay bale storage pads were constructed atthe EORDC farm in 1993 using wet FGD material fromAEP's Conesville plant. The success of thesedemonstration projects led to statewide approval of FGDpads for these two applications using AEP's lime-enriched FGD product.

To date, more than 500 feeding and hay storagepads have been constructed in 12 Ohio Countiessince 1997.

FGD Feedlot Pad

Hay Bale Storage on Constructed FGD Pad

Outreach to General Public:Example of Pervious Concrete

Pervious concrete works like a sieve, allowing water to return to theground and reducing the need for an extensive drainage system.

It is manufactured by leaving most of the sand out of the concretemixture, which is held together with cement, and potentially replacingsome of that cement with fly ash, a coal combustion solid byproduct.

The absence of sand creates small holes that allow rainwater andmelted snow to flow quickly through the concrete. Beneath theconcrete, water is detained in an aggregate reservoir until it passes intothe soil or is released at a designated rate into a storm drain system.

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Our online library collection has been subdivided into the following categories:

Material Characterization

Applications

Economics of Beneficial Use

Our library listing of journal articles, conference papers and published informationsources is related to Coal Combustion Products research. Many of our documentscan be downloaded (typ. as pdf files). For references not available online and notsubject to copyright restrictions, a paper copy can be provided by contacting CarolScott at [email protected].

You are welcome to submit articles for inclusion in our reference library. ContactDr. Tarunjit S. Butalia at [email protected].

Resources Available to You

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M.S. Thesis Dorothy Ann Adams, Swelling characteristics of dry sulfur dioxide removal waste products Jeffreys Chapman, Stress Model Verification with Reclaimed Asphalt PavementMalcolm Damian Hargraves, The effect of freeze-thaw cycles on the strength of stabilized flue gas desulfurization sludge James Robert Howdyshell, Strain compatibility analysis in slope stability modelingJun Huang, Degradation of resilient modulus of saturated clay due to pore water pressure buildup under cyclic loadingNa Jin, Fly Ash Applicability in Pervious ConcreteJames P. Kirch, Potential Use of Flue Gas Desulfurization Gypsum (FGD) in a Flowable Grout for Re-mining of Abandoned Coal Mines Jangguen Lee, The Behavior of Pore Water Pressure in Cohesive Subgrade Soils Jung Woo Lee, Beneficial reuse of FGD by-products as flowable fillYong-Woong Lee, Measurement and Prediction of Resilient Modulus of Lime-Fly Ash Stabilized Cohesive Subgrade Soils Aleia Nicole Long, Evaluating material properties of fly ash modified concrete plates under low velocity impact Ryan Mackos, Environmental Analysis of Full Depth Reclamation Using Coal Combustion By-ProductsDeepa Modi, Potential Utilization of FGD Gypsum for Reclamation of Abandoned HighwallsJennifer Christine Myers, Stabilization of sludge using spray dryer absorber ashSalman Mohammad Nodjomian, Clean-coal technology by-products used in a highway embankment stabilization demonstration projectXueling Pan, The Effect of Freeze Thaw Cycling on the Permeability of Stabilized Flue Gas Desulfurization (FGD) Materials Rachel Pasini, An Evaluation Of FGD Gypsum For Abandoned Mine Land Reclamation Renee Michelle Payette, Landslide Remediation Using Clean Burning Coal Technology By- Products Gloria Rodgers, Resilient modulus predictions using engineering properties and neural networksAlexis Semach, Geotextiles for Use in Drainage Systems in Coal Combustion Product LandfillsSharon Faye Studer, Seepage analysis of a highway embankment constructed from the Flue Gas Desulfurization by-product Wei Tu, Evaluation of Full-Scale CCP Pavement Performance Using Accelerated Loading Facility Michael Nuhfer, Use of flue gas desulfurization by-product as a lake-bed liner

Ph.D. Dissertations Dong-Gyou Kim, Development of a Constitutive Model for Resilient Modulus of Cohesive SoilsSung Hwan Kim, A decision support system for highway embankment design using FGD by-productsJ.W. Lee, Real-Time Monitoring of Landslide Using Wireless Sensor NetworkPanuwat Taerakul, Characterization of trace elements in dry flue gas desulfurization (FGD) by-productsWei Tu, Response Modeling of Pavement Subjected to Dynamic Surface Loading Based on Stress-Based Multi-layered Plate TheoryChin-Min Cheng, Leaching of coal combustion products: field and laboratory studies

Graduate Student Research

Directory of CCP Faculty and Staff

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The OSU CCP program addresses the needs of the industry and helps advance the technically sound,environmentally friendly, and commercially competitive uses of CCPs in many interdisciplinarysustainable applications.

You are invited to have a link from your website to the OSU CCP Program website. We will be glad toreciprocate this, in mutual appreciation.

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