Co-PIs: Erol Tutumluer Marshall R. Thompson RA: Deb Mishra Subgrade Soil Support and Stabilization O’HARE Airport Modernization Research Project Research Progress and Future Tasks – Sept. 21, 2006

Introduction The strength and performance of an airport pavement related to the structural design and the subgrade soil characteristics 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 O’Hare airport pavements This project provides testing and analysis to establish subgrade support and stabilization requirements for O’Hare airport pavements

Research Objectives Consider/Establish subgrade support and stabilization requirements with respect to: Consider/Establish subgrade support and stabilization requirements with respect to: Need for subgrade stabilization Need for subgrade stabilization Selection of lime and other suitable admixture stabilization considerations Selection of lime and other suitable admixture stabilization considerations Stabilization depth Stabilization depth Estimate “subgrade support” for various combinations of subgrade stabilization treatments and prepared subgrade conditions Estimate “subgrade support” for various combinations of subgrade stabilization treatments and prepared subgrade conditions

A project research paper was presented at the 2006 ASCE Airfield and Highway Pavement Specialty Conference, Atlanta, GA, April 30 – May 3, 2006 A project research paper was presented at the 2006 ASCE Airfield and Highway Pavement Specialty Conference, Atlanta, GA, April 30 – May 3, 2006 Published in the Proceedings book Airfield and Highway Pavements, edited by I.L. Al-Qadi Published in the Proceedings book Airfield and Highway Pavements, edited by I.L. Al-Qadi “Characterizing Subgrade Soils and Establishing Treatment Needs for a New Runway at the Chicago’s O’Hare Airport” by H.S. Brar, E. Tutumluer, M.R. Thompson, L. Gosain, and R. Anderson Progress Made In

On April 5th, 2006, the Co-PIs joined a TEL-CON meeting with the OMP concerning the project findings on subgrade stabilization and additional frost action effects. It was recommended that Dr. Dempsey (a participant in the TEL-CON) conduct a climatic-modelling study of the 9-27 RW. On April 5th, 2006, the Co-PIs joined a TEL-CON meeting with the OMP concerning the project findings on subgrade stabilization and additional frost action effects. It was recommended that Dr. Dempsey (a participant in the TEL-CON) conduct a climatic-modelling study of the 9-27 RW. Both North Runway 9L-27R and South Airfield subgrade soil support and stabilization needs were discussed: Both North Runway 9L-27R and South Airfield subgrade soil support and stabilization needs were discussed: effectiveness of lime stabilization on primarily silty soils with low clay contents (less than 20%), effectiveness of lime stabilization on primarily silty soils with low clay contents (less than 20%), adequate strength gain requirements, adequate strength gain requirements, poor workmanship and inadequate construction quality control, poor workmanship and inadequate construction quality control, construction cut off dates for lime treatment effectiveness, construction cut off dates for lime treatment effectiveness, frost penetration effects, and frost penetration effects, and Cement treatment as an option to include in the construction specifications (and use in certain project locations in case lime treatment becomes unsatisfactory for the primarily silty, low clay contents soils to be encountered during subgrade preparation) Cement treatment as an option to include in the construction specifications (and use in certain project locations in case lime treatment becomes unsatisfactory for the primarily silty, low clay contents soils to be encountered during subgrade preparation) Progress Made In

Marshall Thompson traveled to the OMP office on April 11th and participated in a conference at ORD with OMP staff concerning soil stabilization (lime/cement, frost action effects, and use of fly ash as a stabilization admixture) Marshall Thompson traveled to the OMP office on April 11th and participated in a conference at ORD with OMP staff concerning soil stabilization (lime/cement, frost action effects, and use of fly ash as a stabilization admixture) Erol Tutumluer gave a progress update on July 20 th at the OMP office and found out that fly ash was now used for modification of the North Runway soils Erol Tutumluer gave a progress update on July 20 th at the OMP office and found out that fly ash was now used for modification of the North Runway soils Marshall Thompson traveled to the OMP office on July 28 and participated in a conference with OMP staff and 9-27 Design Staff concerning treatment options for “unstable” subgrades. He participated in the subsequent development of recommendations. Marshall Thompson traveled to the OMP office on July 28 and participated in a conference with OMP staff and 9-27 Design Staff concerning treatment options for “unstable” subgrades. He participated in the subsequent development of recommendations. Progress Made In

Professor Barry Dempsey, a UIUC expert on climatic effects has completed a study of frost penetration and freeze-thaw cycle activity for the various 9-27 pavement configurations. The study considered ORD climatic data for the period 1996 – The report has been published as CEAT TN 26. Professor Barry Dempsey, a UIUC expert on climatic effects has completed a study of frost penetration and freeze-thaw cycle activity for the various 9-27 pavement configurations. The study considered ORD climatic data for the period 1996 – The report has been published as CEAT TN 26. Progress Made In

TECHNICAL NOTES 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 Establish the Best Demonstrated Available Technology (BDAT) for subgrade soil evaluation and stabilization Communicate specific findings and recommendations to OMP Communicate specific findings and recommendations to OMPengineers TN5: K-150 Considerations for RW 9-27 TN5: K-150 Considerations for RW 9-27 TN6: Subgrade Strength/Stiffness Evaluation TN6: Subgrade Strength/Stiffness Evaluation TN7: “Working Platform” Requirements for Pavement Construction TN7: “Working Platform” Requirements for Pavement Construction TN8: Subgrade Stability Manual (IDOT) TN8: Subgrade Stability Manual (IDOT) TN13: Moisture Limitations for Lime Stabilization TN13: Moisture Limitations for Lime Stabilization TN14: Admixture Stabilization (Lime Treatment of Subgrades) TN14: Admixture Stabilization (Lime Treatment of Subgrades) TN19: Progress Report on Laboratory Soil Test Results TN19: Progress Report on Laboratory Soil Test Results (March 2006) (March 2006)

DEMPSEY STUDY FINDINGS

TOTAL PVT THICKNESS – 40 INCHES

FROST LINE 46 INCHES 9-27 PAVEMENT

DATEFROST DEPTH (INCHES) DATEFROST DEPTH (INCHES ) AVERAGE 39 INS 9-27 PAVEMENT SECTION

FY 07 Year 3 Project Tasks

Task 1: Cooperate with OMP in the reviewing (and modifying if appropriate) Section P-152 (Excavation and Embankment) and Section P-159 (Lime Modified Soils) or Fly Ash Modified Soil Specs? Experiences (problems/successes) from the current 9-27 contract should be considered Experiences (problems/successes) from the current 9-27 contract should be considered The “modified” versions should be included in future contracts The “modified” versions should be included in future contracts

FY 07 Year 3 Project Tasks Task 2: Cooperate with OMP in the reviewing and modifying Section P-158 (Lime Stabilized Subgrade) for inclusion in the upcoming paving contract Current version cites “latest edition” of IDOT Specs. Should reference the IDOT 2002 version Current version cites “latest edition” of IDOT Specs. Should reference the IDOT 2002 version Modify Spec. (as needed) to include cement as a possible admixture Modify Spec. (as needed) to include cement as a possible admixture Incorporate frost action and freeze-thaw potentials from Dempsey’s study (TN 26) as guidelines Incorporate frost action and freeze-thaw potentials from Dempsey’s study (TN 26) as guidelines Will construction be permitted outside the current April 15 – Sept 15 window? Will construction be permitted outside the current April 15 – Sept 15 window? Other issues?? Other issues??

FY 07 Year 3 Project Tasks Task 3: Evaluate the 9L-27R runway/taxiway soil lime stabilization and (fly ash) modification for meeting the subgrade support (k-value) requirements The research team will support the activities of OMP in: * Characterizing finish grade elevation for “stabilization admixture selection.” * Characterizing finish grade elevation for “stabilization admixture selection.” * Evaluating completed modification/stabilization effort. * Evaluating completed modification/stabilization effort. * Field Validation of completed pavement structure. * Field Validation of completed pavement structure.

FY 07 Year 3 Project Tasks Task 4: Evaluate currently available geotechnical/subgrade data for the South Airfield of the O’Hare Airport with particular emphasis on the stockpiled soils Summarize technology and experiences from North Runway (9-27) and apply to the South Airfield Summarize technology and experiences from North Runway (9-27) and apply to the South Airfield Advise on the soil sampling needs and if considered essential, develop recommendations for additional soil exploration/sampling activities Advise on the soil sampling needs and if considered essential, develop recommendations for additional soil exploration/sampling activities Develop/conduct a laboratory testing program for soil treatment and subgrade support for the South Airfield Develop/conduct a laboratory testing program for soil treatment and subgrade support for the South Airfield

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 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 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 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 O’Hare runways/taxiways. This will be in the form of sustained support for working with OMP on subgrade soil support issues Continue to work with OMP on current and future subgrade soil support and stabilization needs for all O’Hare runways/taxiways. This will be in the form of sustained support for working with OMP on subgrade soil support issues

Any Questions?