Choosing the Right Preservation Treatment for Flexible Pavements

Transcription

1 Choosing the Right Preservation Treatment for Flexible Pavements JAMES S. MOULTHROP, P.E. EX. DIRECTOR, FP 2 INC. AND DAVID PESHKIN, P.E., APPLIED PAVEMENT TECHNOLOGY

2 Presentation Outline Part One (Moulthrop): Pavement Preservation-what is it? Flexible preservation treatments Part Two (Peshkin): Preservation related to Pavement Management Treatment Selection

3 What is FP 2 Inc. An Industry supported trade association Purpose of FP 2 Inc? Promoting the importance of protecting and preserving the huge investment in our nation s pavement infrastructure

4 Supporters Who supports FP 2 Inc? Associations Contractors Material Suppliers Chemical suppliers Equipment manufactures Consultants

5 FP2 Contributors Corporate Sponsors Sponsoring Associations

6 Pavement Preservation-what is it? A program employing a network level, long-term strategy that enhances pavement performance by using an integrated, costeffective set of practices that extend pavement life, improve safety and meet motorist expectations - FHWA Pavement Preservation Expert Task Group

7 Life of Pavement 100 $1 of preventive maintenance here PCI (Pavement Condition Index) 40% Drop in Quality 75% of Life 40% Drop in Quality eliminates or delays spending $8 - $10 on rehabilitation here. 0 Years 12% of Life

8 Pavement Preservation Life Extension Very Good Good Measured Life Extension Fair Poor Very Poor PMS Data Point Time (Years)

9 Distress Index (DI) Remaining Service Life 100 RSL = 9 years RSL = 4 years 80 Treatment A 5 year life ext. Treatment B RSL = 12 years RSL = 2 years 10 year life extension 60 Terminal Threshold 15 yrs 30 yrs Time (Years) 15 20

10 Benefits of Preservation Treatments Retard future deterioration Maintain or improve the functional condition of the pavement system Preserve the pavement system and extend the life Without providing structural improvement Keep Good Roads Good

11 Treatments for Flexible Surfaces 1 Seals Crack Sealing Thin Cold Seals Fog Seal Chip Seal Slurry Seal Scrub Seal Microsurfacing Cape Seal CIR-HIR Plant Mixes Thin/Ultra Thin Hot Mix Asphalt Overlays Warm Mix Dense Graded mixes Porous Friction Courses Bonded wearing course AR modified RAP-RAS Polymers 1 SHRP 2 Report S2-R-26

12 Treatment Options vs. Condition Flexible Pavement Deterioration Curve

13 Flexible Pavement Treatments

14 Treatment of Cracks Crack Filling Lower quality sealant Little preparation For non-working cracks Crack Sealing Higher quality sealant More preparation Working cracks

15 Placement Configurations Flush-Fill Overband Reservoir Combination

16 Performance of Crack Filling Performance life of 2-5 years Timing Temperature not as critical Often conducted prior to surface remediation

17 Performance of Crack Sealing Performance life of 3 to 8 years Timing Moderate temperatures (spring or fall) Most effective if performed right after cracks develop

18 Surface Treatments Fog Seals Slurry Seals Scrub Seals Microsurfacing Seal Coats (Chip Seals)

19 Fog Seals Light application of diluted slow-setting emulsion without aggregate cover Purpose Seal the pavement Inhibit raveling Enrich oxidized asphalt For pavements in good condition Not recommended on high-speed roadways

20 Performance of Fog Seals Most effective on pavements in good condition Minor cracks Some raveling or oxidation Performance life is typically 1 to 2 years Effectiveness improves with repeated applications

21 Slurry Seals Mixture of materials Well-graded fine aggregate Mineral filler (if needed) Slow-setting asphalt emulsion Some systems may contain polymer Thicknesses of 0.12 to 0.5 in. Purpose Reduce moisture damage Improve surface friction

22 Slurry Seal Equipment

23 Performance of Slurry Seals Typical life of 3 to 5 years depending on traffic Reduce development of cracking and raveling Perform better in warmer climates Perform best on pavements in good condition Reflective cracks appear after 1 year

24 Scrub Seals Materials Used Emulsified Asphalt with polymers, crumb rubber or rejuvenating oils Fine aggregate Seal coat aggregate Purpose Mass crack treatment to seal low to moderate severity cracks Eliminate crack sealing Stop raveling Provide surface friction

25 Scrub Seals Crack-filling, sealing, & rejuvenating seal in a series of steps Emulsified asphalt is sprayed and swept with a drag broom into cracks and other surface imperfections Chip spreader applies a layer of fine aggregate, broomed into the surface, followed by a standard chip seal Designed for structurally sound pavements with minor to moderate surface defects Have been used on city streets and highways

26 Scrub Seal Equipment

27 Scrub Seal Performance Estimated life is 4-6 years over pavements in fair to good condition

28 Micro surfacing Mixture of materials Polymer-modified emulsion binder High-quality aggregates Thicknesses 0.4 to 0.8 inches Purpose Improve surface friction Fill ruts/minor surface irregularities Seal pavement surface Open to traffic in 1 hour

29 Micro surfacing Equipment Emulsion and Water Pumps Mix Rate Valve Flow Rate Meters Fines Feeder Secondary Strike-Off Material Feeds Operator Station Spreader Box

30 Performance of Micro surfacing Typically provides service life of 4 to 7 years Effective in rut filling applications Provides high initial friction values Delays development of reflection cracking When underlying cracks are inactive Effective on high & low volume roadways

31 Seal Coats (Chip Seals) Application of binder and aggregate chips rolled into pavement Purpose Seal the pavement Improve surface friction Wearing course

32 Types of Seal Coats Conventional chip seals Rubberized asphalt chip seals Sand seals Sandwich seals Cape seals Can be placed in two or more consecutive layers

33 Seal Coat Operation

34 Performance of Chip Seals Typical performance life of 4 to 7 years Multiple chip seals can increase life (may provide up to 10 years of service)

35 Newer Pavement Preservation Treatments Ultrathin Bonded Wearing Course Fiber reinforced microsurfacing

36 Ultrathin Bonded Wearing Course Ultrathin Bonded Wearing Course Gap-graded polymer-modified HMA placed on a heavy polymer-modified emulsified asphalt membrane Thicknesses of 0.4 to 0.8 in Benefits: Addresses surface distress Reduces noise Increases surface friction

37 Ultrathin Bonded Wearing Course

38 Performance of UTBWC Little long-term performance data (+10 years) Short-term performance promising TX, PA, NH, VT others report pavements in excellent condition after +5 years NCAT Test track Noticeable increase in surface friction No raveling or stripping

39 Recycling Treatments Cold In-Place Recycling Hot In-Place Recycling

40 CIR Equipment Train 40

41 Performance of CIR Typical life of 5 10 years Performance concerns typically associated with: Poor or excessive binder distribution Excessive moisture in the material Improper project selection

42 Available HIR Techniques Heater-scarification Repaving Remixing

43 Heater-Scarifier Heater Scarifier

44 Repaving Equipment

45 Surface Remixing Equipment

46 Remixing Project 46

47 Performance of HIR Typical life depends on the operation Heater-scarification: 3 to 5 years Repaving: 8 to 12 years Remixing: not yet established Pavement must be at least 3 in thick and must have stable base and subgrade

48 Cold Milling Removal of pavement surface using carbide-tipped cutting bits Purpose Restore profiles and slopes Re-establish surface friction Remove layer for recycling Prepare for an overlay

49 Cold Milling

50 Surface After Milling

51 Plant Mix Treatments

52 Thin Lays Thin (0.75 to 1.5 in) plant mixtures of binder and aggregate Dense Graded Porous Friction Course (PFC) Warm Mix Asphalt Stone Matrix Asphalt (SMA) Ultrathin Bonded Wearing Course Purpose Restore rideability Improve surface friction Reduce hydroplaning and tire splash (OGFC)

53 Thin HMA Overlays

54 Q & A

55 4 Thanks for your Participation Please complete the evaluation to provide your feedback on this session and suggest topics for future events. Remember to mark these upcoming events on your calendar! March 7-11,