Co-PIs:Co-PIs: Erol Tutumluer Erol Tutumluer Marshall R. ThompsonMarshall R. Thompson

RA:RA: H.S. BrarH.S. Brar

Subgrade Soil Support Subgrade Soil Support and Stabilizationand Stabilization

O’HARE Airport Modernization Research ProjectO’HARE Airport Modernization Research Project

Introduction

Subgrade performanceSubgrade performance is a key factor in the overall is a key factor in the overall pavement performancepavement performance

National AirportNational AirportPavement Test Pavement Test Facility - Facility - Atlantic City, NJAtlantic City, NJ

This project provides This project provides testing and analysistesting and analysis to establish to establish subgrade support and stabilization requirementssubgrade support and stabilization requirements for O’Hare airport pavementsfor O’Hare airport pavements

P154

P209

Introduction (cont’d)

The preliminary concrete pavement design for the The preliminary concrete pavement design for the O’Hare Modernization Program (OMP)O’Hare Modernization Program (OMP)::

• 15 – 17 inches of PCC Surface15 – 17 inches of PCC Surface• 6-inch Hot Mix Asphalt Base6-inch Hot Mix Asphalt Base• 6-inch Asphalt Treated Permeable Base (!?) 6-inch Asphalt Treated Permeable Base (!?) • ““Stabilized” Subgrade Zone (SSZ)Stabilized” Subgrade Zone (SSZ)• Prepared SubgradePrepared Subgrade

North Runway (9L-27R, 7,500 ft)North Runway (9L-27R, 7,500 ft) paving is scheduled paving is scheduled first for the Spring 2006 (!?)first for the Spring 2006 (!?)

• Stockpiles of local soil on runway centerline (excavated Stockpiles of local soil on runway centerline (excavated from the “Deep Pond” nearby)from the “Deep Pond” nearby)

• Primarily fill and cut areasPrimarily fill and cut areas

Research Objectives

Consider pavement design inputs for subgrade Consider pavement design inputs for subgrade supportsupport

• Modulus of subgrade reaction, kModulus of subgrade reaction, k

Consider subgrade support and stabilization Consider subgrade support and stabilization requirements with respect to:requirements with respect to:

• Need for subgrade stabilizationNeed for subgrade stabilization• Stabilization admixture(s) stabilizationStabilization admixture(s) stabilization• Stabilization depthStabilization depth

Estimate “Estimate “subgrade supportsubgrade support” for various ” for various combinations of subgrade stabilization treatments combinations of subgrade stabilization treatments and prepared subgrade conditionsand prepared subgrade conditions

Project Tasks

Task 1:Task 1:

Establish the Best Demonstrated Available Establish the Best Demonstrated Available Technology (BDAT) for subgrade soil evaluation Technology (BDAT) for subgrade soil evaluation and stabilization and stabilization (Ongoing)(Ongoing)

Reports and publications collected & submitted as Reports and publications collected & submitted as “Technical Notes” on:“Technical Notes” on:

• Subgrade strength/stiffness evaluation techniquesSubgrade strength/stiffness evaluation techniques• Subgrade stability requirements & IDOT ManualSubgrade stability requirements & IDOT Manual• ““Working platform” requirements for pavement Working platform” requirements for pavement

constructionconstruction

Project Tasks

Task 2:Task 2:

Evaluate currently available data for the subgrade test Evaluate currently available data for the subgrade test sections constructed in the Fall of 2003 and the sections constructed in the Fall of 2003 and the necessity/usefulness of constructing additional necessity/usefulness of constructing additional subgrade treatment test sections at O’Haresubgrade treatment test sections at O’Hare

(Effort completed)(Effort completed)

Plate load tests conducted (8/04) on the test sections:Plate load tests conducted (8/04) on the test sections:• Plate 1:Plate 1: 12-inch stabilization/compaction – no admixture 12-inch stabilization/compaction – no admixture• Plate 2:Plate 2: 12-inch quicklime fine (40 lb/yd 12-inch quicklime fine (40 lb/yd22) & fly ash (80 ) & fly ash (80

lb/ydlb/yd22) stabilization) stabilization

• Plate 3:Plate 3: 12-inch quicklime fine stabilization (40 lb/yd 12-inch quicklime fine stabilization (40 lb/yd22) ) • Plate 4:Plate 4: 12-inch lime kiln dust stabilization (40 lb/yd 12-inch lime kiln dust stabilization (40 lb/yd22))

Plate Load Tests Plate Load Tests

Modulus of Subgrade Modulus of Subgrade Reaction, kReaction, k

Project Tasks

Task 3:Task 3:

Advise OMP on current and future test section Advise OMP on current and future test section monitoring and field test evaluation programsmonitoring and field test evaluation programs

(Effort completed)(Effort completed)

Various field tests may be useful to characterize the Various field tests may be useful to characterize the treated subgrade (OMP will arrange for testing):treated subgrade (OMP will arrange for testing):

• Dynamic Cone Penetrometer (8/04)Dynamic Cone Penetrometer (8/04)• Light-Weight Deflectometer (8/04)Light-Weight Deflectometer (8/04)• Clegg Hammer Clegg Hammer • GeogaugeGeogauge• Heavy Weight Deflectometer (HWD)Heavy Weight Deflectometer (HWD)• Ground Penetrating Radar (GPR)Ground Penetrating Radar (GPR)• Seismic Pavement Analyzer, SASW, etc. Seismic Pavement Analyzer, SASW, etc.

Light-WeightLight-WeightDeflectometer Deflectometer

Dynamic ConeDynamic ConePenetrometerPenetrometer

Project Tasks

Task 4:Task 4:

Evaluate currently available geotechnical/subgrade Evaluate currently available geotechnical/subgrade data for the North Runway with emphasis on the data for the North Runway with emphasis on the stockpiled “Deep Pond” soils. Recommend further stockpiled “Deep Pond” soils. Recommend further soil sampling & testing to be conducted (by an OMP soil sampling & testing to be conducted (by an OMP designated testing firm) designated testing firm) (Ongoing)(Ongoing)

Routine tests to establish representative soils Routine tests to establish representative soils existing for the runway subgradeexisting for the runway subgrade

• Grain size distribution (including hydrometer)Grain size distribution (including hydrometer)• Atterberg limits (LL and PL for PI)Atterberg limits (LL and PL for PI)• Moisture-density-CBR Moisture-density-CBR • PH value & calcareous content PH value & calcareous content • If needed, organic matter contentIf needed, organic matter content

Preliminary Geotechnical Report

Soil sampling & testing conducted by Everest Soil sampling & testing conducted by Everest Engineering on OMP Runway 9L-27R - Engineering on OMP Runway 9L-27R - October 2004October 2004

Boring Boring LogsLogs

Atterberg limits Atterberg limits (LL and PL for PI)(LL and PL for PI)

Preliminary Geotechnical Report

Soil sampling & testing conducted by Everest Soil sampling & testing conducted by Everest Engineering on OMP Runway 9L-27R - Engineering on OMP Runway 9L-27R - October 2004October 2004

Grain size distribution Grain size distribution (including hydrometer)(including hydrometer)

Preliminary Geotechnical Report

Soil sampling & testing conducted by Everest Soil sampling & testing conducted by Everest Engineering on OMP Runway 9L-27R - Engineering on OMP Runway 9L-27R - October 2004October 2004

Moisture-density-CBR Moisture-density-CBR

Preliminary Geotechnical Report

Soil sampling & testing conducted by Everest Soil sampling & testing conducted by Everest Engineering on OMP Runway 9L-27R - Engineering on OMP Runway 9L-27R - October 2004October 2004

Unconfined Compressive Strength, Qu Unconfined Compressive Strength, Qu

Soil Sampling: Dec. 04 – Feb. 05

Current scheduled soil sampling & testing from the R9L-27RCurrent scheduled soil sampling & testing from the R9L-27R

The Drilling Program The Drilling Program • Auger borings, 17 boreholes, MT-1 to MT-17 Auger borings, 17 boreholes, MT-1 to MT-17 • 10’ to 45’ depths through fill & cut areas 10’ to 45’ depths through fill & cut areas • All reaching down to elev. 640’ in the natural subgradeAll reaching down to elev. 640’ in the natural subgrade• 3 North of runway, 3 North edge of runway, 4 under 3 North of runway, 3 North edge of runway, 4 under

runway, 2 South edge of runway, 2 between runway and runway, 2 South edge of runway, 2 between runway and taxiway, and 3 under taxiway taxiway, and 3 under taxiway

• SPT and soil sampling at 2.5’SPT and soil sampling at 2.5’• Moisture content, LL, PI, grain size distribution (%clay)Moisture content, LL, PI, grain size distribution (%clay)• Shelby tube samples at each location (638’ to 642’)Shelby tube samples at each location (638’ to 642’)• At least 1 bucket for each major soil in each boreholeAt least 1 bucket for each major soil in each borehole• Two 5-gallon buckets (60-70 lbs./bucket) for each Two 5-gallon buckets (60-70 lbs./bucket) for each

representative soil (composite sample) to test at the representative soil (composite sample) to test at the University of IllinoisUniversity of Illinois

Soil Sampling: Dec. 04 – Feb. 05

University of Illinois input/review – The Drilling ProgramUniversity of Illinois input/review – The Drilling Program

Laboratory Testing NeedsLaboratory Testing Needs• Check the pH of the soil samplesCheck the pH of the soil samples• Check the samples for “free carbonates” by squirting with Check the samples for “free carbonates” by squirting with

10% HCl solution 10% HCl solution • How are the SPT samples handled?How are the SPT samples handled?

““N” counts will be helpful in assessing the mobility N” counts will be helpful in assessing the mobility characteristics (sinkage/rolling resistance) of the characteristics (sinkage/rolling resistance) of the stockpiled soilsstockpiled soils

• What tests are conducted with the Shelby tube samples?What tests are conducted with the Shelby tube samples?

Undisturbed samples obtained from the natural Undisturbed samples obtained from the natural subgrade (finished subgrade elevation) will be best subgrade (finished subgrade elevation) will be best utilized to run unconfined compressive strength and utilized to run unconfined compressive strength and resilient modulus tests resilient modulus tests

Project Tasks

Task 5:Task 5:

Based on the data and information gathered in Task Based on the data and information gathered in Task 4, select (in consultation with OMP) the identified 4, select (in consultation with OMP) the identified representative soilsrepresentative soils and recommend an admixture and recommend an admixture stabilization program stabilization program (Ongoing)(Ongoing)

Tests to be conducted at the Tests to be conducted at the UIUC Advanced UIUC Advanced Transportation Research and Engineering Laboratory Transportation Research and Engineering Laboratory (ATREL)(ATREL) on both untreated & treated soilson both untreated & treated soils

• Moisture-Density-CBR Moisture-Density-CBR • Unconfined Compressive Strength Unconfined Compressive Strength • Resilient ModulusResilient Modulus• Permanent Deformation @ 6-psi deviator stressPermanent Deformation @ 6-psi deviator stress

Project Challenges

Proper sampling of the R9L-27R Proper sampling of the R9L-27R stockpiled soilsstockpiled soils

Selecting & identifying Selecting & identifying representative soil samplesrepresentative soil samples

Adequately characterizing the representative soil Adequately characterizing the representative soil samples by conductingsamples by conducting tests at the UIUC ATREL for tests at the UIUC ATREL for

• Moisture-Density-CBR Moisture-Density-CBR • Unconfined Compressive Strength Unconfined Compressive Strength • Resilient Modulus Resilient Modulus

• Permanent Deformation @ 6-psi deviator stress Permanent Deformation @ 6-psi deviator stress

University of Illinois Laboratory Testing Program at ATREL

Advanced Transportation Research & Engineering Laboratory (ATREL)Advanced Transportation Research & Engineering Laboratory (ATREL)

Admixture Types / Sources

Carmeuse (potential supplier)Carmeuse (potential supplier)South Chicago (dolomitic lime)South Chicago (dolomitic lime)Buffington, IN (high calcium lime)Buffington, IN (high calcium lime)

Lime typesLime typesLime Kiln Dust (LKD)Lime Kiln Dust (LKD)Quicklime finesQuicklime fines

Buffington is the primary sourceBuffington is the primary source

(We will work with this & confirm with S. Chicago)(We will work with this & confirm with S. Chicago)

Moisture-

Density-

CBRCBRCBR

(ASTM D1883)(ASTM D1883)

Proctor Proctor Compaction Compaction

(ASTM D698, (ASTM D698, D1557)D1557)

UntreatedUntreated

Moisture-Density-CBR

Lime treatedLime treated

Lime treatedLime treated

Moisture-Density-CBR

TreatedTreated

LKD: Lime Kiln DustLKD: Lime Kiln Dust

Unconfined Compressive Strength

C C = (= (1f1f)/2 )/2

== Q Quu/2/2

11 1f1f3 3 = 0= 0

dd = = 11 – – 33(=0)(=0)

failurefailure

Cohesive Soils (c, Cohesive Soils (c, =0) =0)

(ASTM D2166)(ASTM D2166)

0

10

20

30

40

50

60

0 5 10 15Axial Strain, %

Ax

ial S

tre

ss, p

si

MC = 28.5 % DD = 93.5 pcfCBR = 4

MC = 23 % DD = 103.5 pcfCBR = 14

MC = 26 % DD = 98 pcfCBR = 8

MC = 30.5 % DD = 92.5 pcfCBR = 2.5

Dupont Clay

Typical Unconfined - Data

QQuu = unconfined = unconfined

compressive compressive strengthstrength

= peak = peak 11

Deviator Stress at Failure

Effect of CuringEffect of Curing

Deviator Stress at Failure

Resilient Modulus Testing

MMRR = resilient modulus = resilient modulus

= = dd / / rr

d d : Deviator stress: Deviator stress

rr : recoverable strain : recoverable strain

Conditioning:Conditioning: 200200 load applications at load applications at 33 = 0, = 0, dd = 41 kPa = 41 kPa

Testing:Testing: 100100 load applications load applications dd = 14, 28, 41, 55, 69, 83, 96, 110 kPa = 14, 28, 41, 55, 69, 83, 96, 110 kPa

dd

Unconfined: Unconfined: 3 3 = 0= 0

2-in. in 2-in. in

MR Tests – Soil Samples

Cylindrical specimens, 2 in. Cylindrical specimens, 2 in. by 4 in. high by 4 in. high

Undisturbed soil samplesUndisturbed soil samples – Shelby tube ( – Shelby tube (= 2.8, 4 in.)= 2.8, 4 in.)

0

4

8

12

16

20

24

28

0 2 4 6 8 10 12 14 16 18

APPLIED DEVIATOR STRESS d (psi)

RE

SIL

IEN

T M

OD

UL

US

MR (

ksi) A-4 soil at OMC A-4 soil at OMC

A-4 soil at OMC+3A-4 soil at OMC+3

MR = - 2.21248 d + 29.696

R2 = 0.9497

M R = - 0.6274d + 1820

R2 = 0.6617

M R = - 0.4203 d + 8.351

R2 = 0.8715MR = 0.0408 d + 4.9412

R2 = 0.8796

Typical MR Characterization

Bilinear or Bilinear or Arithmetic Arithmetic ModelModel

Greensboro, NC Airport Greensboro, NC Airport Subgrade SoilsSubgrade Soils

Resilient Modulus Testing

Resilient Modulus Testing

Resilient Modulus Testing

Project Deliverables

Technical NotesTechnical Notes have been / will be prepared and submitted to have been / will be prepared and submitted to the OMP throughout the project duration to communicate specific the OMP throughout the project duration to communicate specific findings and recommendations to OMP engineersfindings and recommendations to OMP engineers

Several of the Several of the Project TasksProject Tasks are being pursued simultaneously, are being pursued simultaneously, and the specific delivery of results will be contingent upon and the specific delivery of results will be contingent upon availability of OMP data and other factors that depend on availability of OMP data and other factors that depend on coordination with OMPcoordination with OMP

A A ReportReport summarizing the laboratory program will be prepared summarizing the laboratory program will be prepared

A A Final ReportFinal Report will be prepared at the end of the one-year study will be prepared at the end of the one-year study (September/October 2005)(September/October 2005)

We will We will continue to work with OMPcontinue to work with OMP on future subgrade soil on future subgrade soil support and stabilization needs for other runways/taxiwayssupport and stabilization needs for other runways/taxiways

Illini Apparently Have Spent A Little Longer At No. 1 This Time!..

GOGO ILLINI !..ILLINI !..