BCRA Poster

1
Subgrade Soil Support and Stabilization
OHARE Airport Modernization Research Project
Research Progress Presentation January 12, 2006
Co-PIs Erol Tutumluer
Marshall R. Thompson RA
H.S. Brar
2
Introduction

• The strength and performance of an airport
  pavement related to the structural design and the
  subgrade soil characteristics

• This project provides testing and analysis to
  establish subgrade support and stabilization
  requirements for OHare airport pavements

3
Introduction (contd)

• The preliminary concrete pavement design for the
  OHare Modernization Program (OMP)
• 15 17 inches of PCC Surface
• 6-inch Hot Mix Asphalt Base
• 6-inch Asphalt Treated Permeable Base (!?)
• Stabilized Subgrade Zone (SSZ)
• Prepared Subgrade
• North Runway (9L-27R, 7,500 ft) paving is
  scheduled first for the Spring 2006
• Stockpiles of local soil on runway centerline
  (excavated from the Deep Pond nearby)
• Primarily fill and cut areas

4
Research Objectives

• Consider pavement design inputs for subgrade
  support
• Modulus of subgrade reaction, k
• Consider/Establish subgrade support and
  stabilization requirements with respect to
• Need for subgrade stabilization
• Selection of lime and other suitable admixture
  stabilization considerations
• Stabilization depth
• Estimate subgrade support for various
  combinations of subgrade stabilization treatments
  and prepared subgrade conditions

5
Progress Made In 2004-05

• Technical Notes have been prepared and submitted
  to the OMP throughout the project duration to
• Establish the Best Demonstrated Available
  Technology (BDAT) for subgrade soil evaluation
  and stabilization
• Communicate specific findings and
  recommendations to OMP
• engineers
• TN5 K-150 Considerations for RW 9-27
• TN6 Subgrade Strength/Stiffness Evaluation
• TN7 Working Platform Requirements for
  Pavement Construction
• TN8 Subgrade Stability Manual (IDOT)
• TM13 Moisture Limitations for Lime
  Stabilization
• TN14 Admixture Stabilization (Lime Treatment of
  Subgrades)

6
Progress Made In 2004-05

• Subgrade test sections constructed in the Fall of
  2003 and the plate load tests conducted in August
  2004 on these test sections indicated that 12-in.
  quicklime and lime kiln dust (LKD) stabilizations
  were satisfactory
• Plate 3 12-inch quicklime fine stabilization (40
  lb/yd2) ?
• Plate 4 12-inch lime kiln dust stabilization (40
  lb/yd2) ?
• For characterizing the treated subgrade, Dynamic
  Cone Penetrometer and Light-Weight Deflectometer
  tests were performed by OMP designated firms
• It was decided not to construct any new field
  test sections for this purpose

7
Progress Made In 2004-05

• Sampling of the R9L-27R stockpiled soils
• Grain size distribution (including hydrometer)
• Atterberg limits (LL and PL for PI)
• PH value carbonate content
• Selecting identifying representative soil
  samples
• Characterizing the representative soil samples by
  conducting tests at the UIUC ATREL for
• Moisture-Density-CBR
• Resilient Modulus
• Unconfined Compressive Strength
• Lime Treatment Effectiveness
• Final Report summarizing Laboratory Soil Test
  Program Year 1 research activities / findings

8
Soil Sampling Dec. 04 Feb. 05
Everest Engineering - Soil sampling testing
from R9L-27R

• The Drilling Program
• Auger borings, 17 boreholes, MT-1 to MT-17
• 10 to 45 depths through fill cut areas
• All reaching down to elev. 640 in the natural
  subgrade
• 3 North of runway, 3 North edge of runway, 4
  under runway, 2 South edge of runway, 2 between
  runway and taxiway, and 3 under taxiway
• SPT and soil sampling at 2.5
• Moisture content, LL, PI, grain size distribution
  (clay)
• Shelby tube samples at each location (638 to
  642)
• At least 1 bucket for each major soil in each
  borehole
• Two 5-gallon buckets (60-70 lbs./bucket) for each
  representative soil (composite sample) to test at
  the University of Illinois

9
62 Buckets of OMP Soils Arrived at ATREL from the
Drilling Program
MARCH 2005
10
62 Buckets of OMP Soils Arrived at ATREL from the
Drilling Program- contd
MARCH 2005
11
Progress Made In 2004-05

• June 2005 technical report prepared on the
  Laboratory Soil Test Program presented
  preliminary results of the virgin and
  lime-treated soil testing efforts at ATREL
  focused on determining moisture-density-CBR
  relationships, unconfined compressive strengths,
  and resilient modulus properties
• The need for soil stabilization was established
  from these preliminary test results
• A 5 LKD treatment was considered a feasible
  stabilization choice for increasing the strength/
  modulus of the North Runway 9L-27R subgrade soils

12
Progress Made In 2004-05

• A conference paper was submitted accepted for
  presentation and publication in the conference
  proceedings
• Characterizing Subgrade Soils and Establishing
  Treatment Needs for a New Runway at the Chicagos
  OHare Airport
• by H.S. Brar, E. Tutumluer, M.R. Thompson,
  L. Gosain, and R. Anderson
• 2006 ASCE Airfield and Highway Pavement
  Specialty Conference, Atlanta, GA, April 30 May
  3, 2006

13
University of Illinois Laboratory Testing Program
at ATREL
Advanced Transportation Research Engineering
Laboratory (ATREL)
14
Grouping of Soils at ATREL
Boring No. Bucket No. Depth Soil Description Clay () LL () PI () Silt ()
GROUP 1 GROUP 1 GROUP 1 GROUP 1 GROUP 1 GROUP 1 GROUP 1 GROUP 1
MT 14 20 5'-10' Gray SILTY CLAY with Sand 17.6 22 6 54.8
MT 16 17 1'-5' Brown and Gray SANDY LEAN CLAY 19.2 30 17 35.4
MT 4 43 1'-4' Gray LEAN CLAY with sand 22.1 24 8 52.4
MT 3 54 29'-33' Gray SANDY LEAN CLAY 22.1 30 11 39.7
GROUP 2 GROUP 2 GROUP 2 GROUP 2 GROUP 2 GROUP 2 GROUP 2 GROUP 2
MT 3 52 6'-10' Gray SANDY LEAN CLAY 22.8 25 8 44.5
MT 3 51 2'-6' Gray LEAN CLAY with sand 23.5 27 12 49.9
MT 4 44 8'-12' Gray SANDY LEAN CLAY 23.7 24 8 42.9
MT 5 50 33'-36' Gray SANDY LEAN CLAY 25.3 28 10 41.6
Grouping done primarily according to clay
content!..
15
Grouping of Soils at ATREL
Boring No. Bucket No. Depth Soil Description Clay () LL () PI () Silt ()
GROUP 3 GROUP 3 GROUP 3 GROUP 3 GROUP 3 GROUP 3 GROUP 3 GROUP 3
MT 5 47 1'-5' Gray LEAN CLAY with sand 29 33 13 43.2
MT 15 32 1'-5' Gray LEAN CLAY with Sand 29.2 24 9 41.4
MT 10 36 1'-5' Gray LEAN CLAY with Sand 29.4 24 11 39.3
MT 13 3 16'-20' Gray LEAN CLAY with sand 29.7 32 17 50
GROUP 4 GROUP 4 GROUP 4 GROUP 4 GROUP 4 GROUP 4 GROUP 4 GROUP 4
MT 17 24 18'-21' Brown and Gray LEAN CLAY with Sand 39.4 41 24 39.7
MT 8 16 30'-34' Brown and Gray LEAN CLAY with Sand 39.7 38 19 43.3
MT 12 12 30'-35' Brown and Gray LEAN CLAY with Sand 41.9 46 26 42.6
MT 6 27 6'-10' Brown and Gray LEAN CLAY with Sand 43.7 44 18 38
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Test Specimen Preparation
Air Drying
Pulverizing
Mixing
17
Moisture- Density- CBR Results
CBR (ASTM D1883)
Untreated
Proctor Compaction (ASTM D698, D1557)
18
Group 1 Results
Lime Source High Calcium Lime Kiln Dust (LKD)
19
Group 2 Results
Lime Source High Calcium Lime Kiln Dust (LKD)
20
Group 3 Results
Lime Source High Calcium Lime Kiln Dust (LKD)
21
Group 4 Results
Lime Source High Calcium Lime Kiln Dust (LKD)
22
Resilient Modulus (MR) Testing
sd
Unconfined s3 0
2-in. in f
MR resilient modulus sd / er sd
Deviator stress er recoverable strain
Conditioning 200 load applications at s3 0,
sd 41 kPa Testing 100 load applications
sd 14, 28, 41, 55, 69, 83, 96, 110 kPa
23
MR Tests Soil Samples
Cylindrical specimens, 2 in. f by 4 in. high
Undisturbed soil samples Shelby tube (f 2.8,
4 in.)
24
Group 1 MR Test Results
LEDFAA (FAA-AC No. 150/5320-6D, 2004) requires MR
input
Bilinear or Arithmetic Model
Eri
15 to 20 ksi
25
Group 2 MR Test Results
Bilinear or Arithmetic Model
15 to 20 ksi
26
Group 3 MR Test Results
Bilinear or Arithmetic Model
15 to 20 ksi
27
Group 4 MR Test Results
Bilinear or Arithmetic Model
Eri
15 to 20 ksi
28
Unconfined Compressive Strength Test Results
t
sd s1 s3(0)
failure
C (s1f)/2 Qu/2
s1
s1f
s3 0
s

• Cohesive Soils (c, f0)
• (ASTM D2166)

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UCS Without Lime
30
Group 1 with 5 Lime
without lime
Lime Source High Calcium Lime Kiln Dust (LKD)
31
Group 4 with 5 Lime
without lime
Lime Source High Calcium Lime Kiln Dust (LKD)
32
Lime Reactivity
Lime Source High Calcium Lime Kiln Dust (LKD)
Group No. UCS with Lime Qulime (psi) UCS without Lime Qu (psi) Lime Reactivity (Qulime - Qu) (psi)
1 119 80 39
2 184 44 140
3 138 60 78
4 217 74 143
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UCS without Lime After Resilient Modulus (MR)
Testing
Group No. OMC () Sample No. Water Content () Dry Density (pcf) UCS (psi)
1 12.1 1 12.1 122.6 160
1 12.1 2 12.3 122.7 123
2 14.1 1 13.8 118.4 103
2 14.1 2 13.8 119.3 83
3 14.4 1 14.9 116.9 83
3 14.4 2 14.7 118 82
4 18.8 1 19.8 107.5 74
4 18.8 2 19.7 108.2 77
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Summary of Results (1)

• Moisture Density CBR Tests
• Optimum moisture contents of the natural soils
  were always lower those of the same soils treated
  with 5 lime kiln dust (LKD)
• Similarly, maximum dry densities were always
  higher for the natural soils without lime
  treatment
• The unsoaked CBR values obtained from testing the
  compacted specimens tend to drop sharply after
  the optimum moisture contents for the soils
  without lime
• The treated soils with 5 lime always gave much
  higher unsoaked CBR values than the natural soils
  with no lime
• In general, the 5 lime treatment was effective
  for increasing sufficiently the strength of the
  North Runway 9L-37R subgrade soils tested

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Summary of Results (2)

• Resilient Modulus (MR) Tests
• MR decreased with increasing applied deviator
  stresses typical stress-softening fine grained
  soil behavior
• All soil groups tested at the OMC gave high MR
  values at 6 psi deviator stress, in the range of
  Eri 15-20 ksi
• Unconfined Compressive Strength Tests
• Large increases in unconfined compressive
  strengths observed for all groups when 5 lime
  was added
• Lime reactivity (Qu lime treated - Qu natural) is
  greater than 50 psi for all the groups except for
  Group 1
• Minimum lime treated Qu 119 psi was recorded
  for Group 1 soils with the lowest clay contents
  the least reactivity with lime

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Recommendation

• From the results of all tests performed, Green
  Light is given to the 5 lime kiln dust (LKD)
  treatment at the new North Runway 9L-27R of
  OHare International Airport
• seems to be working quite well in increasing the
  soil strengths
• the improvements are sufficient to serve as a
  stabilized subgrade zone and alleviate wet soil
  conditions

37
FY 06 Year 2 Project Tasks

• Task 1
• Conduct additional soil-lime testing in the
  laboratory for soil samples with different lime
  percentages and lime sources
• Establish subgrade support for various
  combinations of subgrade stabilization treatments
  and prepared subgrade conditions
• The data will also be helpful for considering the
  thickness design of the shoulder flexible
  pavements

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Admixture Types / Sources

• Carmeuse (potential supplier)
• South Chicago (dolomitic lime)
• Buffington, IN (high calcium lime)
• Buffington is the primary source and primarily
• worked with in year 1
• Lime types
• Lime Kiln Dust (LKD)
• Quicklime fines

39
Group 2 with Different of LKD
Lime W Dry Density (pcf) CBR CBR Moisture Content,
3 18.6 109.2 6 18.5
7 17.8 108.8 9 17.8
5 18.9 110.2 10 18.6
40
Group 2 with 5 Lime of Different Types
Lime Type W Dry Density (pcf) CBR CBR Moisture Content,
SCLKD 18.6 108.7 11 18.5
BLKD 18.9 110.2 10 18.6
BQL 17.7 109.2 16 17.5
41
Group 2 4 with 3 7 BLKD
Group No. Lime Sample No. Water Content Dry Density (pcf) UCS (psi) Avg. UCS (psi)
2 3 1 15.5 114.3 273 279
2 3 2 15.8 114.5 289 279
2 3 3 16.2 113.5 275 279
2 7 1 15.3 115.7 367 351
2 7 2 15.3 115.8 320 351
2 7 3 15.2 116.4 365 351
4 7 1 22.2 99.7 228 214
4 7 2 22.2 99.8 190 214
4 7 3 22.4 98.8 223 214
42
Group 2 with 3 BLKD
43
Group 4 with 7 BLKD
44
Group 2 with 5 Lime of Different Types
Lime Type Sample No. Water Content Dry Density (pcf) UCS (psi) Avg. UCS (psi)
SCLKD 1 15.9 114.6 281 287
SCLKD 2 15.5 115.3 307 287
SCLKD 3 15.4 114.9 273 287
BLKD 1 15.3 116.8 202 184
BLKD 2 15 116.1 177 184
BLKD 3 15 115.4 174 184
BQL 1 14.3 116.1 311 318
BQL 2 14.0 117.2 327 318
BQL 3 14.2 117.9 317 318
45
Group 2 with 5 SCLKD
46
Group 2 with 5 BQL
47
FY 06 Year 2 Project Tasks

• Task 2
• Provide OMP with guidelines and support for
  monitoring field soil lime stabilization and
  construction of the 9L-27R subgrades
• The research team will provide recommendations on
  the various field tests such as automated dynamic
  cone penetrometer, Clegg hammer,
  Light-Weight-Deflectometer, etc.

48
FY 06 Year 2 Project Tasks

• Task 3
• Evaluate the 9L-27R runway/taxiway soil lime
  stabilization and modification for meeting the
  subgrade support (k-value) requirements
• The research team will support the activities of
  OMP in the evaluation of completed lime
  stabilization
• Project Staff will cooperate with the OMP Project
  Field Validation of Constructed Subgrade and
  Pavement Layers in this effort

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FY 06 Year 2 Project Tasks

• Task 4
• Evaluate currently available geotechnical/subgrad
  e data for the South airfield of the OHare
  International Airport with particular emphasis on
  the stockpiled soils
• Advise on the soil sampling needs and if
  considered essential, develop recommendations for
  additional soil exploration/sampling activities
• The need to construct additional subgrade
  treatment test sections will be considered
• Provide non-routine laboratory testing, such as
  the resilient modulus test, for the soils
  obtained from drilling and sampling and recommend
  and conduct (as time and budget permit) a
  lime-treatment testing program

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Project Schedule Deliverables

• Technical Notes will be prepared and submitted to
  the OMP throughout the duration of this project
  to communicate specific findings and
  recommendations to OMP engineers as needed
• A Final Report will be prepared at the end of the
  one-year study
• Several of the Project Tasks are already pursued
  simultaneously, and the specific delivery of
  results will be contingent upon availability of
  OMP data and other factors that depend on
  coordination with OMP
• Continue to work with OMP on current and future
  subgrade soil support and stabilization needs for
  all OHare runways/taxiways. This will be in the
  form of sustained support for working with OMP on
  subgrade soil support issues

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Any Questions?