490 likes | 638 Views
Full-scale Reflective Cracking Test Update. Presented to: FAA Airport Pavement Working Group Meeting By: Hao Yin, Ph.D., P.E. Gemini Technologies, Inc. Date: April 24, 2012. Acknowledgement. SRA Chuck Teubert Jerry Connelly Renaldo Aponte Jeff Stein
E N D
Full-scale Reflective Cracking Test Update Presented to: FAA Airport Pavement Working Group Meeting By: Hao Yin, Ph.D., P.E. Gemini Technologies, Inc. Date: April 24, 2012
Acknowledgement • SRA • Chuck Teubert • Jerry Connelly • Renaldo Aponte • Jeff Stein • Gupta Durgesh • David Traverzo • Pochtar Daniel • Bing Xiao • Henry Fermin • FAA • Dr. Satish Agrawal • Dr. Gordon Hayhoe • Donald Babargallo • Ryan Rutter • Frank Petch • Murphy Flynn • RMD • Roy McQueen • Christopher Deker
Objective Generate information from full-scale tests (NAPTF) to assist in the improvement of current design procedures for AC overlay on rigid airport pavements.
Scope Evaluate the initiation and propagation of bottom-up reflection cracks due to temperature effect acting alone (thermally induced fatigue), assuming intact PCC slabs. Nunn, M., 1st RILEM 1989
Key Parameters 1. Pavement Temperature: T=32oF, DT=17oF
Key Parameters 2. Horizontal Displacement at Joint: 15 mils
Key Parameters 3. Loading Rate ? 4. AC-PCC Interface Bond ?
Progress Since 2011 • Laboratory tests • Construction, instrumentation, and data collection • Temperature Effect Simulation System (TESS) tune-up and enhancements • Trial test
Determination of Loading Rate Texas Overlay Tester Temp: 32 oF Max Hori Dip: 15 mils Loading Rate: 0.25, 0.50, 1.0 mil/sec
Straight Asphalt steel rake heavy broom Emulsion Interface Bond Experiment
Bond Strength Test Temp: 32 oF Loading Rate: 0.05 mil/sec
PG 64-22 Straight Asphalt and Heavy Broom Bond Strength Test
Pavement Construction P-401 (PG 64-22) 5” P-501 12” 8” P-501 P-209 (Dense Graded Aggregate) 6” Subgrade
Instrumentation Layout South 1.5’ ASG/CSG L ASG/CSG T L L 12.0’ Surface SG T ASG/CSG ASG/CSG L L T L ASG/CSG ASG/CSG T T T T 1.5’ North
Mishap Before Overlay North South
Mishap After Overlay E Force, 92,000 lb Force -85,000 lb Ten Com N S 56 mil -46 mil W
Mishap After Overlay E Com N S Ten W
Trial Test • Feb 27 – March 15 • AC/PCC interface temperature: 32oF • Max Hori Dis: 0.015 in • 600 sec per cycle • 144 cycles per day • Total of 2641 cycles
Hori Dis Along Joint North South
Dynamic Modulus 430,000
Tensile Strength: Field vs. Lab Tensile Strength Field = 200 psi Temperature: 14oF Loading Rate: 8 mil/sec (0.5 in/min) Tensile Strength Lab = 500 psi Buttlar et al. 2011
Crack Development2641 Cycles 37.5” 17”
Future Activities • Experiment instrumentation • Mill existing AC and overlay • Full-scale test • Laboratory tests • Fracture energy of AC • Creep compliance of AC • Tensile strength of AC • Thermal Coefficient of PCC