6th China Asphalt Summit Engineered Ground Tire Rubber (GTR) Modified Binders and GTR Binder Performance Specifications Presented by: Gaylon L. Baumgardner Ergon, Inc. 6th China Asphalt Summit Shanghai, China 26-28 October 2011

6th China Asphalt Summit GLB 10-18-11 Introduction and Background Production of Quality GTR Modified Asphalt Binders Important Parameters Source Evaluation/Asphalt Binder Selection Asphalt Binder Compositional Analysis Ground Tire Rubber Loading Processing Temperature Optimization Ground Tire Rubber Particle Size Optimization Asphalt/Modified Asphalt Specifcations Summary and Conclusions 6th China Asphalt Summit GLB 10-18-11

Introduction and Background

6th China Asphalt Summit GLB 10-18-11 Rubber Reclamation Today markets exist for approximately 80% of scrap tires generated in areas such as recycling into new tires, tire derived fuel and oil products, civil engineering products, recycling into molded/engineered rubber products, agricultural uses, athletic and recreation applications and rubber modified asphalt among others. Presently estimates are less that 10% of scrap tires are disposed of in landfills. 6th China Asphalt Summit GLB 10-18-11

Rubber Modified Asphalt Ground Tire Rubber (GTR) is a post consumer polymer fractionally beneficial in modification of asphalt binders. Benefits of modification of asphalt with GTR are similar to those achieved with virgin synthetic polymers with the exception GTR loadings are typically higher. Knowledge and technology for processing GTR modified binders are just as critical as with synthetic polymer modified binders e.g. SBS In the US, Asphalt Rubber or rubber modified bitumen/asphalt is the largest single market for recycled tires and consumes an estimated 12 million tires annually. 6th China Asphalt Summit GLB 10-18-11

Rubber Modified Asphalt In the US Ground Tire Rubber (GTR) is separated into two particle sizes by class “ground” (2000μm and less) and “coarse” (greater that 2000μm) 6th China Asphalt Summit GLB 10-18-11

Rubber Modified Asphalt Rubber produced from ground whole tires contains ~ 30% reactive material for asphalt modification. Functional yield is dependent of tire composition and asphalt and is directly proportional to rubber particle size and asphalt source. Terminal blending can be an operations challenge without adequate knowledge of asphalt chemistry, GTR source and processing. 6th China Asphalt Summit GLB 10-18-11

Production of Quality GTR Modified Asphalt Binders

6th China Asphalt Summit GLB 10-18-11 Important Parameters Asphalt Binder Source Asphalt Binder Composition GTR Loading/Special Additives Processing Temperatures GTR Source/Particle Size 6th China Asphalt Summit GLB 10-18-11

Asphalt Binder Selection Source Evaluation/ Asphalt Binder Selection

Binder Compositional Analysis

True Grade Range vs. Composition 6th China Asphalt Summit GLB 10-18-11

Effect of Ground Tire Rubber Loading

Typical GTR Loading for PG76-22 in Respect to Asphalt/Source Chemistry 6th China Asphalt Summit GLB 10-18-11

6th China Asphalt Summit GLB 10-18-11 Effect of GTR Loading on Modified Asphalt Properties 6th China Asphalt Summit GLB 10-18-11

Temperature Optimization

6th China Asphalt Summit GLB 10-18-11 Processing Temperature Optimization – Phase Angle 6th China Asphalt Summit GLB 10-18-11

Ground Tire Rubber Particle Size Optimization

6th China Asphalt Summit GLB 10-18-11 GTR Particle Size Optimization – Phase Angle 6th China Asphalt Summit GLB 10-18-11

6th China Asphalt Summit GLB 10-18-11 GTR Particle Size Optimization – Phase Angle 6th China Asphalt Summit GLB 10-18-11

Asphalt/Asphalt Specifications

Grading of Asphalt Binders Prior to 1970 asphalts were specified as penetration grades. 5/9, 50/60, 60/70, 85/100,140/160 and >300 pen Beginning in 1970, asphalts were specified as viscosity grades. AC-5, AC-10, AC-20, AC-30 and AC-40 6th China Asphalt Summit GLB 10-18-11

Grading of Asphalt Binders Continued In the 1990’s State DOT’s began to specify SHRP or Performance Grades of Asphalts. SuperPave™. PG 58-28, PG 64-22, PG 70-22, PG 76-22, etc Though asphalt specifications have been upgraded through time, any of the are previous grading systems are subject to use. 6th China Asphalt Summit GLB 10-18-11

Grading of GTR Modified Asphalt Binders Due to inherent difficulties of testing GTR modified asphalt binders with, penetration, viscosity and performance grading methods, GTR modified binders have been mostly tested with rotational or vane shear viscosity measurements 6th China Asphalt Summit GLB 10-18-11

6th China Asphalt Summit GLB 10-18-11 Modified Bitumen Binder Testing Source:Baumgardner/Anderson-Trans-Polyoctenamer Reactive Polymer/Recycled Tire Rubber Modified Asphalt: Processing, Compatibility and Binder Properties 5th Internatioinal Transporttion Conference Wuppertal DE 2008 6th China Asphalt Summit GLB 10-18-11

6th China Asphalt Summit GLB 10-18-11 Parallel Plate 6th China Asphalt Summit GLB 10-18-11

How to Handle Larger GTR Particle Size? 60 mesh and smaller material is easily handled with 1mm gap 30 to 60 mesh material would require larger, 2mm gap 20 mesh and larger may require larger gaps What is the limit to gap size? Are other geometries available to test larger particles? 6th China Asphalt Summit GLB 10-18-11

Comparison of Measurments at 1 and 2 mm gaps 6th China Asphalt Summit GLB 10-18-11

Parallel Plate DSR Testing 6th China Asphalt Summit GLB 10-18-11

6th China Asphalt Summit GLB 10-18-11 Concerns Large gap requirements due to larger particles Trimming of parallel plates Sedimentation of particulates Deformation of asphalt at geometry surface, rather than entire volume of GTR sample 6th China Asphalt Summit GLB 10-18-11

6th China Asphalt Summit GLB 10-18-11 Cup & Bob Top View 6th China Asphalt Summit GLB 10-18-11

6th China Asphalt Summit GLB 10-18-11 Conventional DSRs Malvern Instruments Kinexus Pro Rheometer Active Heated Chamber Used with 25mm parallel plates Peltier Cylinder Cartridge Used with Cup & Bob and Cup & Vane 6th China Asphalt Summit GLB 10-18-11

New Geometry Evaluation Preliminary testing indicates that new geometry may give similar results Plate/Plate provides similar results to cup and bob Trimming of samples is not required when using cup and bob geometries Accurate measurements can be generated if sedimentation of particulates occurs during the tests using cup and bog geometry 6th China Asphalt Summit GLB 10-18-11

PG Continuous grading for blends using different Geometries BBR PP1 PP2 C&B PAV DSR 6th China Asphalt Summit GLB 10-18-11

MSCR Jnr 0.1kPa Data for various blends 6th China Asphalt Summit GLB 10-18-11

MSCR Jnr 3.2kPa Data for various blends 6th China Asphalt Summit GLB 10-18-11

New CRM spec to match MSCR Binder Spec Original DSR G*/sinδ Min 1.0 64 RTFOT 64 Standard MSCR3.2 <4.0 64 Heavy MSCR 3.2<2.0 64 Very heavy MSCR3.2 <1.0 PAV S grade DSR G*sinδ Max 5000 28 25 22 19 16 H & V grade DSR G*sinδ Max 6000 [(MSCR3.2 – MSCR 0.1)/ MSCR 0.1] < .75 Low temp BBR and DTT remain unchanged

6th China Asphalt Summit GLB 10-18-11 Summary Rubber produced from ground whole tires contains ~ 30% reactive material for asphalt modification. There is nothing to GTR modified asphalt production, that makes it any better or worse than other modifiers, 100% – improved performance modified asphalt can be produced with most all modifiers as long as proper engineering and evaluation is performed. Careful formulation is needed to meet all specifications. Asphalt source and chemistry directly effect rubber loading and the end properties of GTR modified asphalt. Processing parameters Time/Temperature/Processing are important factors. GTR particle size and source greatly effects the efficiency of modification as well as long term performance. 6th China Asphalt Summit GLB 10-18-11

6th China Asphalt Summit GLB 10-18-11 Summary Testing of GTR binders is difficult with standard and perfomance grade methods. Geometries are available for testing of GTR modified binders for performance grade specifications, cup and bob. There may be some differences for GTR modified binders vs. PMA binder specifications. Continued evaluation is underway to evaluate new geometry and develop performance grade specifications for GTR modified asphalt binders. 6th China Asphalt Summit GLB 10-18-11

Thank You!