BCRA Poster

1
Subgrade Soil Support and Stabilization
OHARE Airport Modernization Research Project
Research Progress Presentation June 30, 2005
Co-PIs Erol Tutumluer
Marshall R. Thompson RA
H.S. Brar
2
Introduction

• Subgrade performance is a key factor in the
  overall pavement performance

National Airport Pavement Test Facility -
Atlantic City, NJ

• 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 subgrade support and stabilization
  requirements with respect to
• Need for subgrade stabilization
• Stabilization admixture(s) stabilization
• Stabilization depth
• Estimate subgrade support for various
  combinations of subgrade stabilization treatments
  and prepared subgrade conditions

5
Project Tasks

• Task 1
• Establish the Best Demonstrated Available
  Technology (BDAT) for subgrade soil evaluation
  and stabilization (Ongoing)
• Reports and publications collected submitted
  as Technical Notes on
• Subgrade strength/stiffness evaluation techniques
• Subgrade stability requirements IDOT Manual
• Working platform requirements for pavement
  construction

6
Project Tasks

• Task 2
• Evaluate currently available data for the
  subgrade test sections constructed in the Fall of
  2003 and the necessity/usefulness of constructing
  additional subgrade treatment test sections at
  OHare
• (Effort completed)
• Plate load tests conducted (8/04) on the test
  sections
• Plate 1 12-inch stabilization/compaction no
  admixture
• Plate 2 12-inch quicklime fine (40 lb/yd2) fly
  ash (80 lb/yd2) stabilization
• Plate 3 12-inch quicklime fine stabilization (40
  lb/yd2) ?
• Plate 4 12-inch lime kiln dust stabilization (40
  lb/yd2) ?

7
Plate Load Tests
Modulus of Subgrade Reaction, k
8
Project Tasks

• Task 3
• Advise OMP on current and future test section
  monitoring and field test evaluation programs
• (Effort completed)
• Various field tests may be useful to
  characterize the treated subgrade (OMP will
  arrange for testing)
• Dynamic Cone Penetrometer (8/04)
• Light-Weight Deflectometer (8/04)
• Clegg Hammer
• Geogauge
• Heavy Weight Deflectometer (HWD)
• Ground Penetrating Radar (GPR)
• Seismic Pavement Analyzer, SASW, etc.

9
Dynamic Cone Penetrometer
Light-Weight Deflectometer
10
Project Tasks

• Task 4
• Evaluate currently available geotechnical/subgrad
  e data for the North Runway with emphasis on the
  stockpiled Deep Pond soils. Recommend further
  soil sampling testing to be conducted (by an
  OMP designated testing firm) (Ongoing)
• Routine tests to establish representative soils
  existing for the runway subgrade
• Grain size distribution (including hydrometer)
• Atterberg limits (LL and PL for PI)
• Moisture-density-CBR
• PH value calcareous content
• If needed, organic matter content

11
Preliminary Geotechnical Report
Soil sampling testing conducted by Everest
Engineering on OMP Runway 9L-27R - October 2004
Atterberg limits (LL and PL for PI)
Boring Logs
12
Preliminary Geotechnical Report
Soil sampling testing conducted by Everest
Engineering on OMP Runway 9L-27R - October 2004
Grain size distribution (including hydrometer)
13
Preliminary Geotechnical Report
Soil sampling testing conducted by Everest
Engineering on OMP Runway 9L-27R - October 2004
Moisture-density-CBR
14
Preliminary Geotechnical Report
Soil sampling testing conducted by Everest
Engineering on OMP Runway 9L-27R - October 2004
Unconfined Compressive Strength, Qu
15
Soil Sampling Dec. 04 Feb. 05
Current scheduled soil sampling testing from
the 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

16
Project Tasks

• Task 5
• Based on the data and information gathered in
  Task 4, select (in consultation with OMP) the
  identified representative soils and recommend an
  admixture stabilization program (Ongoing)
• Tests to be conducted at the UIUC Advanced
  Transportation Research and Engineering
  Laboratory (ATREL) on both untreated treated
  soils
• Moisture-Density-CBR
• Unconfined Compressive Strength
• Resilient Modulus
• Permanent Deformation _at_ 6-psi deviator stress

17
Project Challenges

• Proper sampling of the R9L-27R stockpiled soils
• Selecting identifying representative soil
  samples
• Adequately characterizing the representative soil
  samples by conducting tests at the UIUC ATREL for
  
• Moisture-Density-CBR
• Unconfined Compressive Strength
• Resilient Modulus
• Permanent Deformation _at_ 6-psi deviator stress

18
University of Illinois Laboratory Testing Program
at ATREL
Advanced Transportation Research Engineering
Laboratory (ATREL)
19
62 Buckets of OMP Soils Arrived at ATREL from the
Drilling Program
MARCH 2005
20
62 Buckets of OMP Soils Arrived at ATREL from the
Drilling Program- contd
MARCH 2005
21
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!..
22
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
23
Admixture Types / Sources

• Carmeuse (potential supplier)
• South Chicago (dolomitic lime)
• Buffington, IN (high calcium lime)
• Lime types
• Lime Kiln Dust (LKD)
• Quicklime fines
• Buffington is the primary source
• (We will work with this confirm with S.
  Chicago)

so far used in lime treatment
24
Test Specimen Preparation
Air Drying
Pulverizing
Mixing
25
Moisture- Density- CBR Results
CBR (ASTM D1883)
Untreated
Proctor Compaction (ASTM D698, D1557)
26
Group 1 Results

• Moisture-Density

0 Lime 0 Lime 5 Lime   5 Lime  
W () Dry Density ( pcf ) W () Dry Density ( pcf )
10.2 117.89 10.7 110.44
11.9 121.72 13.2 114.30
14.3 118.84 16.3 112.97
16.1 113.27 19.3 107.57
27
Group 1 Results
California Bearing Ratio (CBR)
0 Lime   0 Lime   5 Lime   5 Lime  
W () CBR W () CBR
10.1 44 10.5 77
11.4 22 13.1 61
13.8 5 15.8 16
15.8 2 19.1 5
28
Group 1 Results
29
Group 2 Results

• Moisture-Density

0 Lime   0 Lime   5 Lime   5 Lime  
W () Dry Density ( pcf ) W () Dry Density ( pcf )
12.4 115.36 14 109.81
14.1 119.06 16 114.98
15.8 114.84 18.9 110.23
18.3 108.74 22.4 102.34
30
Group 2 Results
California Bearing Ratio (CBR)
0 Lime   0 Lime   5 Lime   5 Lime  
W () CBR W () CBR
11.7 26 13.2 55
13.4 15 15.9 39
15.7 4 18.6 10
17.6 1 22 4
31
Group 2 Results
32
Group 3 Results

• Moisture-Density

0 Lime 0 Lime 5 Lime   5 Lime  
W () Dry Density ( pcf ) W () Dry Density ( pcf )
12.3 112.85 13.6 107.00
14.4 117.61 17.1 107.65
16.4 113.21 19.8 107.53
18.1 108.75 22.7 102.39
33
Group 3 Results
California Bearing Ratio (CBR)
0 Lime   0 Lime   5 Lime   5 Lime  
W () CBR W () CBR
11.9 27 13.3 55
13.9 13 16.1 35
15.8 4 19.2 13
18 1 22.2 6
34
Group 3 Results
35
Group 4 Results

• Moisture-Density

0 Lime 0 Lime 5 Lime   5 Lime  
W () Dry Density ( pcf ) W () Dry Density ( pcf )
17.2 102.97 16.9 96.91
18.7 105.26 20.0 97.38
21.2 103.77 23.4 98.00
22.9 100.39 26.5 94.30
36
Group 4 Results
California Bearing Ratio (CBR)
0 Lime   0 Lime   5 Lime   5 Lime  
W () CBR W () CBR
16.0 26 16.7 41
18.7 19 19.6 34
20.6 10 22.4 25
22.3 6 26.3 12
37
Group 4 Results
38
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)

39
UCS without Lime
Group No. OMC () Water Content () Dry Density (pcf) UCS (psi)
1 12.1 12.3 122.5 80
2 14.1 14 118.7 44
3 14.4 14.2 118.7 60
4 18.8 19.5 108.2 74
40
UCS Without Lime
41
UCS with 5 Lime
Group No. OMC () Sample No. Water Content () Dry Density ( pcf ) UCS (psi) Avg. UCS (psi)
1 13.8 1 13.3 106.64 109 119
1 13.8 2 13.7 108.5 120 119
1 13.8 3 13.8 109.49 128 119
2 16 1 15.3 116.82 202 184
2 16 2 15 116.11 177 184
2 16 3 15 115.36 174 184
3 18.8 1 17.5 110.43 129 138
3 18.8 2 17.9 110.48 146 138
3 18.8 3 17.9 110.50 138 138
4 22.8 1 22.1 98.2 197 217
4 22.8 2 22.2 98.4 233 217
4 22.8 3 22.1 97.7 221 217
42
Group 1 with 5 Lime
43
Group 4 with 5 Lime
44
Lime Reactivity
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
45
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
46
MR Tests Soil Samples
Cylindrical specimens, 2 in. f by 4 in. high
Undisturbed soil samples Shelby tube (f 2.8,
4 in.)
47
Typical MR Characterization
Greensboro, NC Airport Subgrade Soils
28
24
A-4 soil at OMC
A-4 soil at OMC3
20
Bilinear or Arithmetic Model
16
s
M
- 0.6274
1820

R
d
2
R
0.6617
12
8
4
s
M
- 0.4203
8.351


s
R
d
M
0.0408
4.9412

R
d

2
R
0.8715
2
R
0.8796
0
0
2
4
6
8
10
12
14
16
18
s
APPLIED DEVIATOR STRESS
(psi)
d
48
Group 1 MR Test Results
Eri
49
Group 2 MR Test Results
50
Group 3 MR Test Results
Eri
51
Group 3 MR Test Results
52
Group 4 MR Test Results
Eri
53
Group 4 MR Test Results
Eri
54
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

55
Summary of Results (2)

• 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
• 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

56
Conclusion
From the results of all tests performed, Green
Light is given to the 5 lime kiln dust
treatment which seems to be working quite well in
increasing the soil strengths and, therefore, is
suggested as the stabilization choice for the
subgrade soils at the new North Runway 9L-27R of
OHare International Airport
57
Project Deliverables

• Technical Notes have been prepared and submitted
  to the OMP throughout the project duration to
  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)
• Several of the Project Tasks have been pursued
  simultaneously and coordinated with OMP
• A Report summarizing Laboratory Soil Test Program
  has been prepared. More soil-lime testing will be
  conducted with different lime sources
• A Final Report will be prepared at the end of the
  one-year study (September/October 2005)
• We will continue to work with OMP on future
  subgrade soil support and stabilization needs for
  other runways/taxiways