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Co-PIs: Erol Tutumluer Marshall R. Thompson

Subgrade Soil Support and Stabilization. O’HARE Airport Modernization Research Project. Co-PIs: Erol Tutumluer Marshall R. Thompson RA: H.S. Brar. P209. P154. Introduction.

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Co-PIs: Erol Tutumluer Marshall R. Thompson

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  1. Subgrade Soil Support and Stabilization O’HARE Airport Modernization Research Project Co-PIs: Erol Tutumluer Marshall R. Thompson RA: H.S. Brar

  2. P209 P154 Introduction • Subgrade performanceis 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 O’Hare airport pavements

  3. Introduction (cont’d) • The preliminary concrete pavement design for the O’Hare 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 O’Hare (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/subgrade 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. Soil Sampling: Dec. 04 – Feb. 05 University of Illinois input/review – The Drilling Program Laboratory Testing Needs • Check the pH of the soil samples • Check the samples for “free carbonates” by squirting with 10% HCl solution • How are the SPT samples handled? • “N” counts will be helpful in assessing the mobility characteristics (sinkage/rolling resistance) of the stockpiled soils • What tests are conducted with the Shelby tube samples? • Undisturbed samples obtained from the natural subgrade (finished subgrade elevation) will be best utilized to run unconfined compressive strength and resilient modulus tests

  17. 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 @ 6-psi deviator stress

  18. Project Challenges • Proper sampling of the R9L-27R stockpiled soils • Selecting & identifying representative soil samples • Adequately characterizing the representative soil samples by conductingtests at the UIUC ATREL for • Moisture-Density-CBR • Unconfined Compressive Strength • Resilient Modulus • Permanent Deformation @ 6-psi deviator stress

  19. University of Illinois Laboratory Testing Program at ATREL Advanced Transportation Research & Engineering Laboratory (ATREL)

  20. 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)

  21. Moisture- Density- CBR CBR (ASTM D1883) Untreated Proctor Compaction (ASTM D698, D1557)

  22. Moisture-Density-CBR Lime treated Lime treated

  23. Moisture-Density-CBR Treated LKD: Lime Kiln Dust

  24. Unconfined Compressive Strength t Cohesive Soils (c, f=0) (ASTM D2166) sd = s1 – s3(=0) failure C = (s1f)/2 = Qu/2 s3 = 0 s1f s1 s

  25. 40 30 20 10 0 Typical Unconfined s-e Data 60 Dupont Clay MC = 23 % 50 DD = 103.5 pcf CBR = 14 Qu = unconfined compressive strength = peak s1 MC = 26 % DD = 98 pcf CBR = 8 Axial Stress, psi MC = 28.5 % DD = 93.5 pcf CBR = 4 MC = 30.5 % DD = 92.5 pcf CBR = 2.5 0 5 10 15 Axial Strain, %

  26. Deviator Stress at Failure

  27. Deviator Stress at Failure Effect of Curing

  28. Resilient Modulus 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

  29. MR Tests – Soil Samples Cylindrical specimens, 2 in. f by 4 in. high Undisturbed soil samples – Shelby tube (f = 2.8, 4 in.)

  30. s M = - 2.21248 + 29.696 R d 2 R = 0.9497 (ksi) R RESILIENT MODULUS M Typical MR Characterization Greensboro, NC Airport Subgrade Soils 28 24 A-4 soil at OMC A-4 soil at OMC+3 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

  31. Resilient Modulus Testing

  32. Resilient Modulus Testing

  33. Resilient Modulus Testing

  34. Project Deliverables • Technical Notes have been / will be prepared and submitted to the OMP throughout the project duration to communicate specific findings and recommendations to OMP engineers • Several of the Project Tasks are being 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 • A Reportsummarizing the laboratory program will be prepared • 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

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

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