Pennsylvania s Experience with Thin Asphalt Overlays

Transcription

1 Pennsylvania s Experience with Thin Asphalt Overlays Northeast Asphalt User Producer Group Annual Meeting Newark, DE October 20, 2016 Mansour Solaimanian, PhD, PE Penn State University 1

2 Outline 1 THMAO As A Pavement Preservation Strategy 2 Mix Design and Evaluation Construction Quality Control Performance Evaluation 2

3 1 THIN OVERLAYS FOR PAVEMENT PRESERVATION 33

4 PennDOT Research Project on THMAO n Four Year Project: June 2012 June 2016 n Initiated by PAPA/PennDOT n Included Three Demonstration Projects n Research Team: n Penn State (Prime Contractor) n Advanced Infrastructure Design n Quality Engineering Solutions, Inc. n Penetradar Corporation 4

5 Pilot Projects 55

6 Roadway Improvement Activities Activity Reconstruction Major Rehabilitation Minor Rehabilitation Pavement Preservation Preventive Maintenance Routine Maintenance Increase Capacity Increase Structural Strength? Improve Pavement Condition Restore Serviceability Extend Service Life Depends 6

7 How Thick is Thin Asphalt? n Placed up to 1.25 inches in thickness n Ultrathin layers: between 0.5 and 1.0 7

8 Practice in Other States State Term Type Sieve mm IN MI NC Ultrathin Bonded Wearing Course HMA Ultra- Thin Ultrathin Bonded Wearing Course 4.75mm mm %Pass Thickness, in 3/4-1 3/4 1/2 1 Mostly 5/8

9 Practice in Other States State Term Type Sieve mm NY OH TX 6.3 mm Polymer Modified HMA Smoothseal Crack Attenuating Mix (CAM) Type A Type B %Pass (Max) Thickness, in 3/4-1 5/8 3/4 3/4-1

10 Mat Thickness/NMAS Ratio NMAS: Nominal Max. Aggregate Size Aggregate NMAS Mat Thickness 0.5 to 1.25 in 3 Ratio of Thickness to NMAS

11 Importance of NMAS in Thickness Table shown with: Mat Thickness: from 1.5 inches to 0.50 inches, and NMAS: from 12.5 mm to 4.75 mm Good Ok Avoid 111 Mat Thickness In mm NMAS Ratio

12 Significance of Aggregate Skid Resistance Level in Thin Asphalt Two of the Most Important Properties Affecting Friction (Skid Resistance) Are: 1. Aggregate Microtexture 2. Pavement Macrotexture 12

13 Significance of SRL in Thin Asphalt Micro (texture of stone) Macro (texture of road) As thickness gets smaller, harder to develop macro and more demand on micro. 13

14 2 MIX DESIGN AND EVALUATION 1414

15 6.3 mm NMAS Mix Placed at 1 inch thickness Aggregate: Skid Resistance Level (SRL): E Polymer Modified Binder: PG (for heavier traffic) Gyration Level: 75 Design Air Void: 4%, Min. Design VMA: 16.5% Design Binder Content: 6.7%; 7.0%; 6.9% NO RAP/RAS 15

16 Percent Passing (%) SR 0220 SR 0230 SR mm NMAS Mix Aggregate Gradation of Three Pilot Projects # 200 # 50 # 16 # 8 # 4 6.3mm 9.5mm 16 Sieve Size

17 Performance Evaluation - HWTD Specimens under water Test Temperature: 50ºC 20,000 Passes 50 Passes per minute 158-lb load 17

18 Performance Evaluation - HWTD 6 5 Thin Asphalt Overlay Project Hamburg Wheel Tracking Tests - 8/23/ st Pilot Project SR 0022 Rut Depth, mm Right Track Left Track 1 Temperature = 50ºC Number of Wheel Passes (X1000) 18

19 Performance Evaluation Texas Overlay Tester 19

20 Performance Evaluation Overlay Tester Test Temperature: 25ºC # of load cycles: 1000 Or until load reduced to 93% of original Repeated loading (triangular form) under constant deformation Deformation magnitude per load cycle: inches (0.6 mm) Duration of each load cycle: 10 seconds 20 Cycles to failure > 500 Good Performance

21 Tack Coat Evaluation Direct Shear Applied at the Asphalt-Concrete Interface Horizontal Load Asphalt Counterbalancing Moment Tack Coat Horizontal Load Counterbalancing Moment 21 Concrete

22 Tack Coat Evaluation Trimmed Core Tested Specimen in Direct Shear 22

23 Interface Shear Stress, KPa Tack Coat Evaluation Shear Strength = 44.5 psi (307 KPa) - Good Performance THMAO Project Tack Coat Evaluation - Core # 5 Deformation Rate: 1 mm/min Test Temperature: 25.5 C Interface Shear Deformation, mm 23

24 Recommended Requirements for Design of Asphalt Mix for Thin Lifts Asphalt Binder n PG or PG 64E-22 if ESALs > 3M n PG if ESALS 3M n PG or PG 64E-22 if grade 5% regardless of traffic level. Mix Design n 75 Gyrations n Air Void: 4.0% n VMA: 16.5% 2424

25 Recommended Requirements for Design of Asphalt Mix for Thin Lifts Aggregate, SRL E AGGREGATE GRADATION REQUIREMENTS, PERCENT PASSING Sieve Size Min. Max. 3/8 100 Min. 1/ No Max No No No Pilot Projects %Pass#

26 Recommended Requirements for Design of Asphalt Mix for Thin Lifts Tack Coat, CSS-1h Surface Type Residual Application Rate (Gallons/Square Yard) New Asphalt Mixture 0.03 to 0.04 Oxidized Asphalt Mixture 0.04 to 0.06 Milled Asphalt Mixture 0.05 to 0.07 Milled PCC 0.05 to 0.07 Portland Cement Concrete to 0.07

27 3 CONSTRUCTION OF THIN OVERLAYS 2727

28 Repair/Prepare the Base 2828

29 Repair/Prepare the Base 2929

30 Repair/Clean before Tacking 30

31 Emulsion Tack Coat Application 31

32 Rollers Follow Paver Closely Concern with Mat Temperature 3232

33 Mat Temperature 33

34 Finished Overlay SR

35 SR 230 Finished Overlay 35

36 SR 220 Finished Overlay 36

37 4 QUALITY CONTROL OF THIN OVERLAYS 3737

38 Mat Temperature Infrared Measurements 38

39 Thermal Segregation DT 25 ºF 25<DT 50 ºF DT> 50 ºF Mild Moderate Severe Less Temp. Variation More Uniformity More Temp. Variation More Variability 3939

40 Pave-IR TM for thermal profiling n Continuous Temperature Measurement Using Infrared Sensor Bars n Gives Paver Speed, Idle Time, Position 40

41 Pave-IR TM for thermal profiling 41

42 Coring for Density & Lab Testing 42

43 Ground Penetrating Radar AID Integrated Testing Vehicle Courtesy of Advanced Infrastructure Design, Inc. Can GPR provide a reliable estimate of mat density? 43

44 Air Coupled GPR 44

45 Dielectric Distribution Map Distance from Edge (ft) Distance from Start (ft) LOW dielectric area (estimated HIGH air voids) HIGH dielectric area (estimated LOW air voids) 45

46 GPR Dielectric-Air Void Relationship 46

47 5 PERFORMANCE OF THIN OVERLAYS 4747

48 Performance SR 0022 Before paving Nov., months afer paving 48

49 Performance SR months after paving 4949

50 45 months after paving Performance SR

51 Performance SR months after paving 5151

52 SR 230 Before THMAO 52

53 SR 230 Performance 34 months after paving 5353

54 SR 230 Performance 34 months after paving 5454

55 SR 220 Performance 32 months after paving 555

56 SR 220 Performance 32 months after paving 5656

57 Skid Resistance Results 57

58 Friction Improvement SR Average Skid Number vs. Month of Service Constructed in July Skid Number Data: Courtesy of PennDOT BOMO Months from Construction 5858

59 Friction Improvement SR Average Skid Number vs. Month of Service Constructed in June Skid Number Data: Courtesy of PennDOT BOMO Months from Construction 5959

60 SR Friction Improvement Average Skid Number vs. Month of Service Constructed in September Skid Number Months from Construction Data: Courtesy of PennDOT BOMO 6060

61 Rutting 6161

62 SR Rutting Average Rut Depth vs. Month of Service SR22 Constructed in July 2012 Rut Depth (in.) Average Travel Average Passing Data: Courtesy of PennDOT BOMO Months from Construction 6262

63 SR Rutting Average Rut Depth vs. Month of Service SR230 Constructed in June 2013 Travel Lane Passing Lane Rut Depth (in.) Data: Courtesy of PennDOT BOMO Months from Construction 6363

64 SR Rutting Average Rut Depth vs. Month of Service SR220 Constructed in September 2013 Average Travel Avearage Passing Rut Depth (in.) Data: Courtesy of PennDOT BOMO Months from Construction 6464

65 Ride Quality & Smoothness 65

66 Ride Quality (Smoothness) Improvement SR Average IRI vs. Month of Service SR 0022 Constructed in July IRI (in./mile) Average Travel Average Passing Months from Construction Data: Courtesy of PennDOT BOMO 66

67 Ride Quality (Smoothness) Improvement SR IRI vs. Month of Service SR230-Seg 290 East Travel Lane Constructed in June 2013 Left WP Right WP IRI (in./mile) Months from Construction Data: Courtesy of PennDOT BOMO 67

68 Ride Quality (Smoothness) Improvement SR IRI vs. Month of Service SR220-Seg 10 North Passing Lane Constructed in September 2013 Left WP Right WP IRI (in./mile) Months from Construction Data: Courtesy of PennDOT BOMO 68

69 Summary Thin Asphalt A Good Tool for Surface Treatment Proper Base Repair is a MUST Improved Ride and Friction Improved Ride and Friction Maintained Minimal Rutting Observed 69

70 Summary Concerns: Rapid Mat Cooling Reflection of cracks is a challenge on jointed or cracked pavement Advanced Tech for Quality Control: GPR-Density results are promising Thermal Imaging Good Mix Lab Performance: Rutting and Moisture Resistance (HWTD) Crack Resistance (Texas Overly Test) 70

71 Thank You! 71 71