1. US Army Corps of Engineers BUILDING STRONG ® US Army Corps of Engineers BUILDING STRONG ® Airfields and Pavements Research Overview J. Kent Newman, Phd John Rushing Mariely Mejias Jonathon Griffin Greg Norwood Geotechnical and Structures Laboratory November 9, 2011

2. BUILDING STRONG ® Outline  Introduction ► APB Mission and History  Selected Research Project Summaries ► Flowable Fill for Rapid Pavement Repair ► Warm-Mix Asphalt Guide Specifications ► Pavement Preservation ► Geogrid-Reinforced Pavement Designs

3. BUILDING STRONG ® Introduction  APB Mission ► Tri-Service (Army, Navy, Air Force) Lead R&D Agency ► Design, construction, evaluation, rehabilitation, and maintenance of structural systems for pavements, rails, and other transportation facilities to support DOD infrastructure and global force projection. ► Responsibilities - Materials, Design, Models Development, Performance Evaluation and Prediction, Forensic Analyses, Criteria Development, Rehabilitation, and Repair HVS-A

4. BUILDING STRONG ® History of Corps Airfields and Pavements Research 1940 19501960 1980 1990 1970 Design and construction criteria for B-29 Heavy-load (B-52) pavements Landing mats Fuel and blast resistant pavements Airfield evaluations C-5A, B-747 criteria Vietnam Unsurfaced criteria Nondestructive testing procedures PCI Bomb-damage repair FRC pavements Layered-elastic design HVS-A Testing AAF Evaluation program Railroad program RCC, RMP pavements Polymer-Modified Asphalts 3-D finite element modeling Advanced materials characterization Rapid Airfield Construction CBR Design Improvement Rapid Airfield Repair AM-X Mat Program Asphalt Mix Design 20002012

5. BUILDING STRONG ® Flowable Fill for Rapid Pavement Repair  Mixture properties influence performance  Pavements constructed with rapid-setting flowable fill can withstand numerous high load traffic applications  When compared to traditional compacted aggregate, repairs are easily and rapidly completed at reduced in- place cost

6. BUILDING STRONG ® Optimized Flowable Fill Placement  Military Problem ► Optimized tactics, techniques, and procedures (TTP) are required to increase backfill production rate and reduce the time required to repair damaged airfield pavements.  Objective ► To evaluate material, equipment, and process alternatives for increasing efficiency and production rate of rapid-setting flowable fill.

7. BUILDING STRONG ® Optimized Flowable Fill Placement  Approach ► Field examination of technologies increasing production rate when employing traditional wet mixed flowable fill modified dry placement techniques to increase flowable fill performance  Equipment Alternatives ► Rapid Material Loader ► Ready-Mix Transit Truck ► CRATR Simplified Volumetric Mixer  TTP Modification ► Front Load Mix Water ► Mobile Drum Mixer ► Soil Mixing Attachment (CTL) ► Handheld Concrete Mixer

8. BUILDING STRONG ® Optimized Flowable Fill Placement

9. BUILDING STRONG ® Optimized Flowable Fill Placement

10. BUILDING STRONG ® Optimized Flowable Fill Placement  Status ► 18 trials in concrete pavement completed ► 3 trails in asphalt pavement pending ► Water front loading TTP modification successfully exhibited during CRATR Cold-Weather Demonstration, Malmstrom AFB, MT ► Working with AFRL on evaluation of short-term flowable fill performance under compaction equipment

11. BUILDING STRONG ® Warm-Mix Asphalt Guide Specifications  Objective: ► Develop specifications for the use of warm-mix asphalt on military airfield pavements.  Scope: ► Lab study using 24 mixes: 3 WMA technologies and RAP ► Site visits to verify mix production, construction and performance from field projects. HMAWMA NCAT Test Track

12. BUILDING STRONG ® Warm-Mix Asphalt for Airfield Pavements  Current: ► Evaluate field performance of WMA mixtures under military aircraft loading ► Evaluate lab performance of plant-produced mixtures ► Develop a test protocol for product approval 12

13. BUILDING STRONG ® Approach  Accelerated Pavement Testing: ► 3 WMA technologies and HMA ► F-15 Traffic  Laboratory Evaluation: ► 11 WMA technologies and HMA ► Plant-produced and lab-produced mixes  Rutting: ► APA – 250 psi ► APA – 325 psi  Hamburg  Moisture Damage  TSR ► Hamburg ► Recovered Binder PG grade

14. BUILDING STRONG ® 65 ft 130 ft 12 ft 24 ft Item 3 Item 4 Item 1 Item 2 N Accelerated Pavement Testing F-15E HVS Temperature-controlled: ≈ 40 °C Failure Criteria: 1 in. rut depth 100,000 passes ItemDescription 1HMA (Control) 2Sasobit ® 3Evotherm™ 4Foamed Asphalt Asphalt Limestone (100 CBR) Clay Gravel (30 CBR) Subgrade (15 CBR) 4 in. 10 in. 24 in.

15. BUILDING STRONG ® Lawson AAF Wheeler Sack AAF Dover AFB Davis Monthan AFB Robert Gray AAF Hurlburt Field Pavement Preservation Initiatives  Objective ► To provide guidance for preventive maintenance on HMA airfield pavements to reduce rate of environmental degradation.  Scope ► Conduct long-term evaluation of performance of asphalt surface treatments in airfield pavements while ensuring adequate friction and resistance to FOD generation

16. BUILDING STRONG ® Pavement Preservation Initiatives

17. BUILDING STRONG ® Evaluation of Geogrids for Airfield Pavements  OBJECTIVE: ► Quantify the performance benefits of geogrid reinforced aggregate bases under aircraft loading ► Develop specifications to facilitate selection of geogrid products which will provide acceptable performance benefits, ► Develop design guidance with a method of determining the appropriate decrease in base course thickness when geogrid products are used for base reinforcement.

18. BUILDING STRONG ®  APPROACH: ► Full-scale test section ► 4-inch HMA surface course ► 8 CBR subgrade ► Control, 7 different commercially available geogrid products with grid placed at base/subgrade interface ► Flexible pavement ► 14-inch 100 CBR base course ► 9 test items ► One item with a repeat geogrid product placed mid depth in the base course layer Evaluation of Geogrids for Airfield Pavements

19. BUILDING STRONG ® 19 Single Depth Deflectometers Moisture/Temperature Probe Geogrid Strain Gauges Earth Pressure Cells Asphalt Strain Gauges Pore Water Pressure Transducers Instrumentation

20. BUILDING STRONG ® Evaluation of Geogrids for Airfield Pavements  Accelerated Pavement Testing: ► Traffic with the HVS-A ► 45,000 lb wheel load, 142 psi ► Constant pavement temperature of 77° F ► C-17 single wheel ► 48” wander pattern normally distributed ► Evaluate rut depth, surface deformations, and instrumentation response at selected traffic intervals

21. BUILDING STRONG ® Questions?