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Binder Characterizations for High Tire Pressure Project. 04/26/2012 Injun Song , Ph.D., P. E . SRA International, Inc . Federal Aviation Administration Airport Pavement Working Group Meeting Atlantic City Convention Center April 24 – 26, 2012 Atlantic City, NJ. Acknowledgements.
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Binder Characterizationsfor High Tire Pressure Project 04/26/2012 Injun Song, Ph.D., P. E. SRA International, Inc. Federal Aviation Administration Airport Pavement Working Group Meeting Atlantic City Convention Center April 24 – 26, 2012 Atlantic City, NJ
Acknowledgements • Binder Testing; • Yusuf A. Mehta, Rowan University. • APA Testing; • Jeff Stein, SRA International, Inc. • Matthew Wilson, SRA International, Inc. • Roy D. McQueen, Roy D. McQueen & Associates Ltd. • NavneetGarg, Federal Aviation Administration. • Gordon Hayhoe, Federal Aviation Administration.
Background • Needs for New High Tire Pressure Limit; • The advent of new aircraft having tire pressures exceeding 220 psi, • International Civil Aviation Organization (ICAO) Standard. • New Design Procedures; • Concentrating in the surface layers of the pavement structure, • Developing Hot Mix Asphalt (HMA) mix design procedures.
Objectives • Characterizations of the HMA properties affecting the performance of HMA mixes under high pressure aircraft tires; • Full-Scale testing at the National Airport Pavement Test Facility (NAPTF), • Laboratory testing for HMA and asphalt binder. • Conducting researches into the design of HMA to resist damage from high pressure aircraft tires.
Outline • Confirming Performance Grades. • Multi Stress Creep Recovery. • Frequency Sweep Test for Temperature Dependency. • Temperature Susceptibility for HMA.
Materials for Lab Testing • Fifteen Mixtures Combining Three Aggregates with Five Binder Types. • Three Aggregate Types; • NAPTF mix (Argillite & Dolomite), • Lexington mix (Limestone), • JFK (Granite). • Five Binder Types; • Neat PG 64-22, • Neat PG 70-22, • Blend of Neat PG 64-28 + 25% Trinidad Lake Asphalt (TLA), • Polymer modified PG 76-22, • Polymer modified PG 82-22.
NAPTF Mixtures • Used for NAPTF Full-Scale and Asphalt Pavement Analyzer (APA). • Mix Design; • Aggregates: Argillite and Dolomite, • Binder: PG 64-22 and PG 76-22 at 105°F and 119°F. • Loading Conditions; • Inflation pressure for the north wheel=210 psi / south wheel=245 psi, • Simulate Taxiway Traffic Loading: West to East at 1.0 ft/sec. Return East to West at 4.0 ft/sec, • Wander spacing=0 and ±7 inches / Wander sequence: -1, +1, 0.
Tests for Binder Characterization • Dynamic Shear Rheometer (DSR); • G*, d, • Multiple Stress Creep Recovery (MSCR), • AASHTO T 315; Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR), • AASHTO TP 70; Multiple Stress Creep Recovery (MSCR) Test of Asphalt Binder Using a Dynamic Shear Rheometer, • AASHTO M320; Standard Specification for Performance-Graded Asphalt Binder. • Rolling Thin Film Oven (RTFO). • Pressure Aging Vessel (PAV). • Rotational Viscometer. • Softening Point / Elastic Recovery (PG+).
Superpave PG High Temperature • G*/ sin d; • >1.00 kPa for unaged. • >2.20 kPa after RTFO for production process during storing, mixing, transportation, and lay down, • SuperpaveBinder Specification inversely proportional to rutting potential, • Well for conventional speed and moderate traffic volume. • Grade Bumping; • Losing linear viscoelastic behavior with excessive loading time (speed) and heavy traffic (volume),
FAA Grade Bumping • FAA Advisory Circular 150/5370-10F;
AASHTO Grade Bumping • AASHTO MP-2, “Standard Specification for Superpave Volumetric Mix Design”;
Multi Stress Creep Recovery • Eliminate Grade Bumping; • Grade bumping not reflects experiencing high temperature. • Better Characterization of the High Temperature Performance Properties. • Testing; • DSR after Short-Term Aging (RTFO), • 10 cycles per stress level at 0.1kPa and 3.2kPa, • 1 second loading and 9 second resting periods, • Non-Recoverable Creep Compliance ().
MSCR Gradings() • ) / ≤ 0.75
MSCR Gradings (Traffic) • Example; NJ 20mil ESAL, PG 64-22 → PG 64-22V
APA Test Results 2000 600
Summary • Binder Characterizations; • Confirming current binder gradings used for high tire pressure project, • Applications of MSCR for the current binders. • Temperature Susceptibilities for Binder and HMA.