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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.

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Presentation on theme: "Long-Life Pavements Concepts and Lab Testing Pre-bid Meeting Solano 80 04-4A0104 James M. Signore Oakland, CA 9/14/2012."— Presentation transcript:

1 Long-Life Pavements Concepts and Lab Testing Pre-bid Meeting Solano A0104 James M. Signore Oakland, CA 9/14/2012

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

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

4 Long Life Pavement – What is it? Repeated Bending Leads to Fatigue Cracking Repeated Deformation Leads to Rutting HMA Base Subgrade

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

6 Long Life Pavements in the US

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

8 Project Considerations Materials Selection & Testing Structural Design Specs tructionConstruction

9 Recent Projects Weed I-5 D2Weed I-5 D2 Red Bluff I-5 D2Red Bluff I-5 D2

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

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

12 What to Anticipate Solano 80

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

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)

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 +/- X Total of 9 specimens per mix (3 x 3BC) SELECT OBC based on SHEAR test results FATIGUE 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 SOBC – 1 Test, 50C, 4 cores If Fail Testing

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

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

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

19 SPECIMEN FABRICATION Shear & Fatigue Beams and Cores cut from HMA Ingot (Example)

20 SPECIMEN FABRICATION Shear & Fatigue Beams and Cores cut from HMA Ingot

21 SPECIMEN FABRICATION Shear & Fatigue

22

23

24 FATIGUE BEAMS

25 Protection of Beams in transit/shipping is essential – no bending or flexing of packaging

26 SPECIMEN FABRICATION Hamburg Superpave Gyratory CompactorSuperpave Gyratory Compactor

27 SPECIMEN FABRICATION Hamburg Hamburg Testing Fixture – cut ‘flat’ on coresHamburg Testing Fixture – cut ‘flat’ on cores

28 LABORATORY TESTING SHEAR TESTINGSHEAR TESTING FATIGUE TESTINGFATIGUE TESTING HAMBURG TESTINGHAMBURG TESTING

29 SHEAR TESTING

30

31 SHEAR CORE – Post Test Note Shear or “Slope” of specimen

32 SHEAR TESTING Permanent Shear Strain (PSS) “Rutting” Cycles Spec Minimum to pass 5% PSS

33 FATIGUE TESTING

34 Flexural Stiffness (FS) Cycles (millions) Spec Minimum to pass 50% FS (typical) Not to scale

35 HAMBURG WHEEL TRACKING (Moisture Sensitivity)

36 Rut Cycles Theoretical “Rut Resistant”

37 HAMBURG WHEEL TRACKING (Moisture Sensitivity)

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 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 (min) 870,000 to 1,000, Fatigue (min. repetitions) At 400x10-6 in./in. strain At 200x10-6 in./in. strain AASHTO T-321 Modified 6% +/- 0.3% 23,000, ,000,000 25, ,000 Moisture Sensitivity (min. repetitions) AASHTO T-324 Modified 7% +/- 1% 12,000 12,000

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

40 Stabilometer Variability Based on these numbers, the 5 th percentile is about 80% of the average (mean)

41 Questions? Acknowledgements: Rita Leahy, Professor Monismith, Caltrans Staff


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