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Chapter 6 Chip Seals From… Maintenance Technical Advisory Guide (MTAG)

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Presentation on theme: "Chapter 6 Chip Seals From… Maintenance Technical Advisory Guide (MTAG)"— Presentation transcript:

1 Chapter 6 Chip Seals From… Maintenance Technical Advisory Guide (MTAG)

2 Manager’s Overview From… Maintenance Technical Advisory Guide (MTAG)

3 Introduction to Chip Seal What is Chip Seal? Why use Chip Seal? When to use Chip Seal? Where to use Chip Seal? Chip Seal Variations

4 What Is Chip Seal Description Application of asphalt binder on existing pavement followed by a layer of aggregate chips. The treatment is then rolled to embed the aggregate into the binder.

5 Performance and Cost -Why to Use Performance Proper application of binder and aggregate Proper embedment Typical treatment life: 4 to 7 years Average cost $0.96/m 2 to $1.32/m 2 ($0.80 to $1.10/yd 2 )

6 Surface for light to medium traffic Waterproof layer Skid resistant surface Restore weathered surface Address bleeding Temporary base course cover Define shoulders Where and When to Use

7 When NOT to Use! Structurally deficient pavements Cracks >6 mm (0.25 in) wide Medium- to high-severity alligator cracking Large number of potholes Rutting >25 mm (1 in) Very rough surface

8 Keys for Success Proper surface preparation Use the right emulsion and clean aggregates Determine the appropriate spread rates for the emulsion and the aggregate Follow the construction specs, including the need for traffic control Chip seal in good weather conditions CHIP SEALS

9 Sweeping (before and after) Rolling Aggregate Application Binder Application

10 Proper Application

11 Loose Chips BleedingStreaking

12 Chip Seal Variations Single chip seals Double or triple chip seals Cape Seals Sand seals Fabric and chip seals

13 Chip Seal Variations Single Chip Seals Existing Pavement Pneumatic- Tired Roller Binder

14 Chip Seal Variations Double Chip Seals Existing Pavement Binder Pneumatic- Tired Roller Second Binder Application Pneumatic- Tired Roller

15 Chip Seal Variations Cape Seals Existing Pavement Pneumatic- Tired Roller Binder Slurry Seal Brooming

16 Chip Seal Variations Sand Seals Existing Pavement Pneumatic- Tired Roller Binder

17 Chip Seal Variations Fabric and Chip Seals Existing Pavement Tack Coat Paving Fabric Binder Application Pneumatic- Tired Roller

18 Chip Seal Variations Fabric and Chip Seals

19 Chip Seal Course Training Modules Available 1. Design, Materials & Specifications 2. Construction, QC & Trouble Shootings

20 End Overview Begin Project Design, Materials & Specifications

21 Design, Materials & Specifications From… Maintenance Technical Advisory Guide (MTAG) Module 6-1

22 Design, Materials & Specifications 22 Topics to be covered Chip Seal Design Process Design Considerations -Quantity Selection Chip Seal Design Methods Material Selection – Binder and Aggregate

23 Chip Seal Design Process Assess existing pavement Select chip seal variation Select compatible binder and aggregate Quantity selection

24 Design Considerations Quantity Selection Residual asphalt content Asphalt cement factor = 1.0 Emulsion factors range = 0.55 to 0.65 Aggregate application rate Single chip layer No more than 10% excess chips 70% embedment recommended

25 Chip Seal Design Methods McLeod procedure Asphalt Institute method

26 Asphalt Institute Method 1. Determine aggregate size and specific gravity 2. Aggregate and asphalt emulsion quantities from table 3. Adjust aggregate (if necessary) 4. Adjust asphalt content based on condition of road (if necessary)

27 Workshop Chip Seal Design Problem Break into groups Work design problem in Participant’s Workbook Present findings to class

28 Material Selection Binder

29 Material Selection Binder Rapid setting emulsions Polymer-modified emulsions Asphalt cement Rubberized asphalt

30 Asphalt Water Emulsifying agent (surfactant) Material Selection Emulsion Ingredients

31 Material Selection Emulsion Classification Electrical charge (+ or – ) Speed of break: slow (SS), medium (MS), and rapid set (RS) Asphalt relative viscosity: hard (h) or soft (s) Polymer-modified asphalt (P or L) High float (HF)

32 Emulsion Type Slow Setting Medium Setting Rapid Setting AnionicSS-1 SS-1h MS-1 MS-2 MS-2h HFMS-1 HFMS-2 HFMS-2h HFMS-2s RS-1 RS-2 HFRS-2 CationicCSS-1 CSS-1h CMS-2 CMS-2h CRS-1 CRS-2 Material Selection Emulsion Classification

33 Material Selection Rubberized Asphalt Chip Seal

34 Binder Material Field Blended using hot asphalt, extender oil and crumb rubber.  Oil application is usually.60 gal / square yard through an agitated distributor truck attached with a vapor recovery system. Aggregate Chip  Chips are always hot pre-coated, and applied at lbs. per square yard Hot Rubber Chip Seals

35

36 Asphalt Rubber Chip Seal

37 Binder Terminal Blended using hot asphalt, polymer and can use crumb rubber.  Application rate is gals/sy depending on size of chip Chips  Chips can be 3/8” up to 1/2” (25-35 lbs. / sy)  Chips can also be pre-coated but not required Polymer Modified Chip Seals

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39 Polymer Modified Emulsion Chip Seals Crack Seal before PM Emulsion Seal

40 Binder Polymer modified emulsion with a solvent free rejuvenating agent additive  Application rate is gals/sy depending on size of chip and degree of cracking. Chips  Chips can be 1/4” up to 1/2” (18-35 lbs. / sy)  Can be applied at temperatures down to 40 o F  Crack filling is not required PM Emulsion Rejuvenating Chip Seals

41 Material Selection Aggregates Clean and durable One size : 6 to 16 mm (0.25 to 0.6 in) Cubical shape Flat and elongated particles limited to 25 to 30 percent Fines limited to 1 to 2 percent

42 Existing Pavement Pneumatic- Tired Roller Binder Material Selection Problem With Flat Aggregates

43 Design, Materials & Specifications 43 End Project Design, Materials & Specifications Begin Construction, QC, and Trouble Shooting

44 Construction and Inspection From… Maintenance Technical Advisory Guide (MTAG) Module 6-2

45 Construction & Inspection 45 Construction Procedures Quality Control Inspection Troubleshooting Topics to be covered

46 Construction

47 Construction Conventional Chip Seal Procedure 1. Clean existing pavement 2. Apply binder 3. Spread aggregate 4. Roll 5. Allow binder to cure 6. Broom loose aggregate

48 Construction Cleaning Existing Pavement

49 Construction Start and Stop Application on Mat

50 Construction Binder Application

51 Spray Bar and Nozzles Single Overlap Construction Binder Overlap h h Roadway Surface Double Overlap Roadway Surface Triple Overlap Roadway Surface h

52 Construction Binder Application Overlap Triple Overlap

53 Construction Binder Application

54 Construction Aggregate Application

55

56 Immediate rolling of aggregate Pneumatic-tired rollers No fewer than three passes Full coverage necessary before asphalt hardening Construction Rolling

57

58

59 Time depends on temperature and relative humidity Emulsion break should begin just after first roller pass Open to traffic in about 2 hours Construction Curing of Binder

60 Construction Brooming Loose Aggregate

61 Project review Document review Material checks Quality Control Preliminary Responsibilities

62 Surface preparation Equipment inspection Asphalt distributor Chip spreader Haul trucks Rollers Brooms Quality Control Pre-Application Inspection

63 Weather requirements Determining application rates Checking application rates Traffic control plan and setup Quality Control Pre-Application Inspection (continued)

64 Asphalt application Aggregate application Truck operation Rolling Longitudinal joints Transverse joints Brooming Quality Control Project Inspection

65 Cleanup Opening to traffic Quality Control Post-Application Inspection

66 Project review Document review Material checks Quality Control Preliminary Responsibilities

67 Surface preparation Equipment inspection Asphalt distributor Chip spreader Haul trucks Rollers Brooms Quality Control Pre-Application Inspection

68 Weather requirements Determining application rates Checking application rates Traffic control plan and setup Quality Control Pre-Application Inspection (continued)

69 Asphalt application Aggregate application Truck operation Rolling Longitudinal joints Transverse joints Brooming Quality Control Project Inspection

70 Cleanup Opening to traffic Quality Control Post-Application Inspection

71 Project review Document review Material checks Quality Control Preliminary Responsibilities

72 Surface preparation Equipment inspection Asphalt distributor Chip spreader Haul trucks Rollers Brooms Quality Control Pre-Application Inspection

73 Weather requirements Determining application rates Checking application rates Traffic control plan and setup Quality Control Pre-Application Inspection (continued)

74 Asphalt application Aggregate application Truck operation Rolling Longitudinal joints Transverse joints Brooming Quality Control Project Inspection

75 Cleanup Opening to traffic Quality Control Post-Application Inspection

76 Troubleshooting

77 Troubleshooting What is wrong here? Streaking

78 Troubleshooting What is wrong here? Poor Longitudinal Joint

79 Troubleshooting What is wrong here? Bleeding

80 Troubleshooting What is wrong here? Loss of Cover Aggregate

81 Troubleshooting What is wrong here? Inadequate Aggregate Coverage

82 Problem: Troubleshooting Possible Construction Problems Aggregate embedment > 80 percent Potential causes?

83 Problem: Troubleshooting Possible Construction Problems Aggregate embedment < 50 percent Potential causes?

84 Troubleshooting What is wrong here? Loss of aggregate due to inadequate curing

85 Troubleshooting What is wrong here? Single Overlap

86 Troubleshooting What happened here?

87 Questions?


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