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Long-Life Pavements Concepts and Lab Testing Pre-bid Meeting Solano 80 04-4A0104 James M. Signore Oakland, CA 9/14/2012 Slide 2 Presentation Overview Long Life Pavement (LLP) What it is? What are the benefits? Recent California Experience I-5 in Red Bluff and Weed What to Anticipate Specimen Preparation & Lab Testing Slide 3 Long Life Pavement What is it? Design Life 40+ years Bottom-Up Design and ConstructionBottom-Up Design and Construction Renewable Pavement Surface High Rutting and Cracking ResistanceHigh Rutting and Cracking Resistance Smooth and Safe Driving SurfaceSmooth and Safe Driving Surface Slide 4 Long Life Pavement What is it? Repeated Bending Leads to Fatigue Cracking Repeated Deformation Leads to Rutting HMA Base Subgrade Slide 5 Long Life Pavement What are the Benefits? Lower Life Cycle Cost Better Use of Resources Low Incremental Costs for Surface Renewal Lower User Delay Cost Fewer or Shorter Work Zone Periods for Future Maintenance Slide 6 Long Life Pavements in the US Slide 7 Structural Section SOLANO 80OGFC HMA w/ 15% Max. RAP (PG 64-28PM) HMA w/ 25% RAP (PG 64-10) Geosynthetic Interlayer Existing Pavement 2 Mix Designs!!! Leveling Course Slide 8 Project Considerations Materials Selection & Testing Structural Design Specs tructionConstruction Slide 9 Recent Projects Weed I-5 D2Weed I-5 D2 Red Bluff I-5 D2Red Bluff I-5 D2 Slide 10 Structural Section Weed HMA w/ 15% Max. RAP (PG 64-28PM) HMA w/ 25% RAP (PG 64-16) HMA w/ 25% RAP (PG 64-16) (leveling course) 2 Mix Designs!!! NTS Existing Cracked & Seated PCC or HMA SAMI* * Asphalt Rubber Seal Coat Slide 11 Structural Section Red BluffOGFC HMA w/ 15% Max. RAP (PG 64-28PM) HMA w/ 25% RAP (PG 64-10) HMA-Rich Bottom (PG 64-10) CTB-Existing Agg Subbase & Subgrade 3 Mix Designs!!! NTS Slide 12 What to Anticipate Solano 80 Slide 13 Mix Design based on Mechanistic Lab Testing Hveem (CT 366)Hveem (CT 366) Shear Testing (T-320)Shear Testing (T-320) Fatigue Testing (T-321)Fatigue Testing (T-321) Hamburg WT (T-324)Hamburg WT (T-324) Mix must meet performance requirements in Special ProvisionsMix must meet performance requirements in Special Provisions Slide 14 Modified (Mechanistic) Mix Design Process Establish target binder content with Hveem (CT 366) Performance Testing 1.Shear testing at target binder content X 2.Select design binder content based on shear test results 3.At design binder content Fatigue Hamburg Wheel Track (HWT) Slide 15 M odified Mix Design Flow Chart HVEEM Mix Design for Target OBC H SHEAR Testing to determine OBC S 3 specimens prepared and tested at HBC + 3 more each @ +/- X Total of 9 specimens per mix (3 x 3BC) SELECT OBC based on SHEAR test results FATIGUE Testing @ OBC S Flexural Fatigue 20C, 2 levels of strain (bending) 6 Total (6 x 1BC) Flexural Stiffness - 20C & 30C 6 Total (6 x 1BC) Spare beams recommended 14 Total if possible HWTD testing @ SOBC 1 Test, 50C, 4 cores If Fail Testing Slide 16 M odified Mix Design Materials and Time HVEEM to determine target BC SHEAR Cores are prepared first Testing performed to determine OBC S Requires 3 x 3BC Cores (6 in. diameter x 2 in. tall) Cores are prepared with Rolling Wheel Compaction (RW) OBC based on SHEAR test results FATIGUE Beams prepared after OBC S determined 6 Flexural Fatigue (2 in. tall x 2.5 in. wide x 15 in. long) 6 Flexural Stiffness (2 in. tall x 2.5 in. wide x 15 in. long) Beams are prepared with Rolling Wheel Compaction (RW) HWTD Testing Cores are 6 in. diameter x 2.5 in. tall 1 Test with 4 cores prepared with Superpave Gyratory (SGC) Time Per Mix 3 wks 6 wks 1 wk Slide 17 Quantity of Materials Per Mix Design Caltrans Project TypicalLong Life Hveem Mix Design (includes CT 371) 5 gal binder ~500 lb aggregate 5 gal binder ~500 lb aggregate Performance Testing (includes specimen fabrication) 10 gal binder ~ 1,200 lb aggregate (Plant Mix Equivalent) Shear Fatigue Hamburg Slide 18 SPECIMEN FABRICATION Shear & Fatigue Caltrans LLP AC2 Sample Preparation Design and Testing for Long Life Hot Mix Asphalt Pavements AASHTO PP3-94 Rolling Wheel Compaction Slide 19 SPECIMEN FABRICATION Shear & Fatigue Beams and Cores cut from HMA Ingot (Example) Slide 20 SPECIMEN FABRICATION Shear & Fatigue Beams and Cores cut from HMA Ingot Slide 21 SPECIMEN FABRICATION Shear & Fatigue Slide 22 Slide 23 Slide 24 FATIGUE BEAMS Slide 25 Protection of Beams in transit/shipping is essential no bending or flexing of packaging Slide 26 SPECIMEN FABRICATION Hamburg Superpave Gyratory CompactorSuperpave Gyratory Compactor Slide 27 SPECIMEN FABRICATION Hamburg Hamburg Testing Fixture cut flat on coresHamburg Testing Fixture cut flat on cores Slide 28 LABORATORY TESTING SHEAR TESTINGSHEAR TESTING FATIGUE TESTINGFATIGUE TESTING HAMBURG TESTINGHAMBURG TESTING Slide 29 SHEAR TESTING Slide 30 Slide 31 SHEAR CORE Post Test Note Shear or Slope of specimen Slide 32 SHEAR TESTING Permanent Shear Strain (PSS) Rutting Cycles Spec Minimum to pass 5% PSS Slide 33 FATIGUE TESTING Slide 34 Flexural Stiffness (FS) Cycles (millions) Spec Minimum to pass 50% FS (typical) Not to scale Slide 35 HAMBURG WHEEL TRACKING (Moisture Sensitivity) Slide 36 Rut Cycles Theoretical Rut Resistant Slide 37 HAMBURG WHEEL TRACKING (Moisture Sensitivity) Slide 38 SPECIFICATIONS and Testing Variability Design Parameters Test Method Sample Air Voids Requirement HMA (15% Max RAP, Long Life) HMA (25% RAP, Long Life) Permanent deformation (min. stress repetitions) AASHTO T-320 Modified 3% +/- 0.3% 360,000 360,000 Beam Stiffness (psi) At 20 C and 10 Hz At 30 C and 10 Hz AASHTO T-321 Modified 6% +/- 0.3% 415,000 to 486,000 220,000 (min) 870,000 to 1,000,000 -- Fatigue (min. repetitions) At 400x10-6 in./in. strain At 200x10-6 in./in. strain AASHTO T-321 Modified 6% +/- 0.3% 23,000,000 345,000,000 25,000 950,000 Moisture Sensitivity (min. repetitions) AASHTO T-324 Modified 7% +/- 1% 12,000 12,000 Slide 39 SPECIFICATIONS and Testing Variability Specifications for Shear and Fatigue are statistically based The specifications are based on the lowest 5 percentile expected from testing Comparable mixes should pass this specification 95 out of 100 times Limits are set low to accommodate large testing variability present in Shear and Fatigue Testing Slide 40 Stabilometer Variability Based on these numbers, the 5 th percentile is about 80% of the average (mean) Slide 41 Questions? Acknowledgements: Rita Leahy, Professor Monismith, Caltrans Staff