Rubber Pavement Association Technical Advisory Board Meeting 11 July 2002San Diego, California Asphalt Rubber Research Kamil E. Kaloush Arizona State University
AR Research Background at ASU • Started July 2001 • Obtain Typical Engineering Material Properties for AR Mixtures and Binders • >>> 2002 Design Guide • Compare the Laboratory Performance of AR Mixtures To Conventional ADOT Mixtures • Special Studies: Field - Laboratory Comparison
Research Partners Arizona State University
Completed 2nd Project: Nov 01 – Nov 03 I-17 Frontage Rd. AR Demonstration Program On-Going Current Projects 1st Project: Jul 01 – Jun 02 I-40 Buffalo Range Sections
Satisfy Research Needs • Project 2: PG Binder Specifications for AR Binders. • Project 8: Database of Asphalt Rubber Projects. • Project 10: Evaluate AR Using 2002 Design Guide Test Protocols. • Project 11: Laboratory and Field Evaluation
Current Projects 3rd Project: Jul 02 – Jan 03 Alberta AR Test Section Starting Soon! 4th Project: ALF Test Section
On Going Asphalt-Rubber Technology Research Center (ARTIC) Library Update • Project 3: Document Merits of Asphalt Rubber Products • Project 5: Individual Technical Merit Documents Research Needs
I-40 Buffalo Range • One Stock Binder (58-22). • Gap / Open Graded Mixes. • Binder Tests. • Mixture Tests on HMA. • In-situ Air Voids I-40 MP 229
AR Demonstration Program • Acting as a Catalyst to Expand the Environmental Responsible Use of Crumb Rubber • Demonstrate the Use of Ground Tire Rubber in Asphalt Pavement Construction • >> Nationwide Implementation.
Project Ends Pinnacle Peak Rd. Project Start
Mainly PG 64-16 / (Test Section 58-22). Gap Graded Mix Binder and HMA Testing Lab Experimental Design on HMA 3 Compaction Levels 2 Aging Levels Field Specimens Reflective Cracking Model Verification (CONSULPAV: Dr. Jorge Sousa) AR Demonstration Program
Binder Tests • Conventional Tests • Penetration AASHTO T49-93 • Softening Point AASHTO T53-92 • Rotational Viscosity AASHTO TP48 • Superpave / SHRP Tests • Dynamic Shear Rheometer (DSR): AASHTO PP1 • Bending Beam Rheometer (BBR): AASHTO TP1-98
ASU Experience in AR Binder Handling / Testing • Heating: Needs Additional 15 to 20 min • Use Continuous & Rigorous Stirring • RTFO : Spill Over (~ 20%) • Brookfield: Select Proper Spindle
Pen 59, 77oF Soft. Point 139oF Brookfield Viscosity 200-350oF Buffalo Range (PG58-22 + R)
Comparison With PG 76-16 Binder RTFO PAV
Mixture Tests: NCHRP 9-19 SPT Candidates Triaxial Compression • Dynamic Modulus (E*) • Flow Time (FT) – (Static Creep Test) • Flow Number of Repetitions (FN) – (Repeated Load Test)
Phase Lag in Dynamic Loading 3 to 200 psi Confinement E* Dynamic Modulus Testing
Secondary Tertiary FT Defines Time When Shear Deformation Begins Primary Creep Test - Rutting Stress s Time
ep = N b a 2 2 14 14 16 16 FN (Flow Number) Repeated Load Test - Rutting Load Number of Cycles (N) 0.9 s 0.1 s er MR Permanent Strain (in/in) N
Cracking Tests Indirect Tensile Creep Test • Creep Compliance • Strength
Cracking Tests Flexural Fatigue Tests SHRP M-009
εt E Nf 2002 Design Guide Generalized fatigue equation for mixed loading mode:
Thermal Cracking As Tensile Strain Indirect Tensile Strength Tests
Thermal Cracking As Fracture Energy Indirect Tensile Strength Tests
Summary • The Conventional Binder Tests are Adequate in Describing the Viscosity-Temperature Susceptibility (A-VTS) of Crumb Rubber Modified Binders. • This A-VTS Relationship Also Appears to Relate to Observed Field Performance Behavior. • Less Low-Temperature Cracking • Good Resistance to Rutting at High Temperatures.
Summary • Corelok is a Useful Device for Measuring Mixture Air Voids, Especially ACFC Mixes • E*AR Mixes ~ E* Conv. Mixes(Note Va %) • Permanent Deformation (PD)Tests: > ARAC Good Resistance to Deformation
Summary • Tensile Strength: No Advantages of AR Mixes • Strain at Failure • Fracture Energy were Better Indicators of Field Performance • Fatigue Relationships: AR-ACFC and ARAC Mixtures Provides Much Better Fatigue Life Than Dense Graded PG 76-16 Mix.
Acknowledgment • George Way, Julie Nodes, Doug Forstie, ADOT • Mark Belshe, FNF Construction • Donna Carlson, Doug Carlson, RPA • Andy Acho, Ford Motor Company • Matthew Witczak, ASU • ASU Advanced Pavement Laboratory Staff / GRA’s • Kenny Witczak, Javed Bari, Mohammad Abojaradeh, Aleksander Zborowski, Andres Sotil Thank you !