Chapter 11 Bonded Wearing Course

1
Chapter 11Bonded Wearing Course

• From Maintenance Technical
• Advisory Guide (MTAG)

2
Managers Overview

• From Maintenance Technical
• Advisory Guide (MTAG)

3
Introduction to BondedWearing Course (BWC)

• What is BWC ?
• Why use BWC?
• When to use BWC?
• Where to use BWC?

4
What is BWC?

• A thin Hot Mix Asphalt Overlay placed over an
  emulsion membrane which
• seals the existing pavement
• bonds the two surfaces
• The roadway is open to traffic very quickly
• This process is done in a single machine

5
What is BWC?
Emulsion membrane wicks up around the HMA
aggregates
The emulsion cures, bonding the mix pavement
Existing Pavement
6
BWC Specification SSP 39-700

• High quality aggregate
• Restores retains friction
• Gap-Graded or
• Open Graded Gradation
• Modified PG Binder or
• Rubberized AC
• Mix designed specially for process

7

• 12 year old surface US 281, TX

Why use BWC?
8
Lark Ellen LA County 12/10/98
Performance
Before
After
Lark Ellen LA County 12/10/2005
9
Construction Speed and Quick Return to
Traffic(7- 15 minutes)
Why use BWC
Front Street in Sacramento May 15, 2003
10
When to use?Site Selection Guidelines
I-77 Columbia, SC Dry, Oxidized, Slightly
Rutted Pavement, 60,000 ADT

• Structurally sound pavement
• Rut depth
• Minor to moderate transverse longitudinal
  cracking
• Bleeding minor to moderate
• Raveled

11
When NOT to use! Poor Candidates
High Severity Block Cracking
High Severity Alligator Cracking
Rutting 1/2
High Severity D Cracking
12
Hwy 73 BWC
Hwy 99 RBWC

• Where to use?Noise reductionNight WorkReduced
  BacksprayHigh Volume RoadwaysQuick return to
  traffic

13
Where/Why to usecontinued

• Quick return to traffic- Reduced Work Zone Time
  (Workers Safety)
• Noise Reduction- Open/Gap Graded Mix
• Night Work- Min Temp 45º F (More working days)
• Reduced Backspray- Open/Gap Graded Mix
• High Volume Roadways- Faster Paving Process (Get
  In- Get Out)

14
Bonded Wearing CourseTraining Modules Available

• Design, Materials Specifications
• Construction Inspection

15
End OverviewBegin Project Design, Materials
Specifications
16
Design, Materials Specifications
Module 11-1

• From Maintenance Technical
• Advisory Guide (MTAG)

17
Topics to be covered

• Project Selection
• Distress and Other Application Considerations
• Performance
• Cost
• Design Considerations
• Mobilization
• Typical Materials Items
• Quantity Calculations
• Production Rates
• Roadway Widths
• Roadway Geometry
• Traffic Control
• Miscellaneous Items
• Sample Project
• Materials and Specifications (including SSPs)
• Summary

18
Project Selection

• Distress and Application Considerations
• Performance

19
Factors to Consider When Choosing a Maintenance
Treatment

• Will the treatment address the distresses
  present? (i.e., Will it work?)
• Can the required preparation for the treatment be
  carried out?
• Is the treatment affordable and cost effective?
• Will the treatment be performed before the
  situation being addressed changes?

20
Three Basic Steps In The Selection Process

• Assess the existing conditions.
• Determine the feasible treatment options.
• Analyze and compare the feasible options with
  each other.

21
Initial Site Assessment Distress Identification

• Types of Distresses and Definitions
• Definitions from
• DISTRESS IDENTIFICATION MANUAL for the Long-Term
  Pavement Performance Program
• PUBLICATION NO.
• FHWA-RD-03-031
• JUNE 2003

22
FATIGUE CRACKING
LOW
MODERATE
HIGH
23
BLOCK CRACKING
24
EDGE CRACKING

• Applies only to pavements with unpaved
  shoulders. Crescent-shaped cracks or fairly
  continuous cracks which intersect the pavement
  edge and are located within 0.6 m of the pavement
  edge, adjacent to the shoulder.

Edge Cracking on Lift Prior to Overlay
25
LONGITUDINAL CRACKING
SEVERITY LEVELS LOW A crack with a mean width 6
mm or a sealed crack with sealant material in
good condition and with a width that cannot be
determined. MODERATE Any crack with a mean width
6 mm and 19 mm or any crack with a mean
width 19 mm and adjacent low severity random
cracking. HIGH Any crack with a mean width 19
mm or any crack with a mean width 19 mm
and adjacent moderate to high severity random
cracking.
Moderate Severity Longitudinal Cracking in the
Wheel Path
26
REFLECTION CRACKING
Severity Levels LOW An unsealed crack with a
mean width 6 mm or a sealed crack with
sealant material in good condition and with a
width that cannot be determined. MODERATE Any
crack with a mean width 6 mm and 19 mm or
any crack with a mean width 19 mm and adjacent
low severity random cracking. HIGH Any crack with
a mean width 19 mm or any crack with a mean
width 19 mm and adjacent moderate to high
severity random cracking.
High Severity Reflection Cracking
27
TRANSVERSE CRACKING
High Severity
Medium Severity
Any crack with a mean width 6 mm and 19 mm
or any crack with a mean width 19 mm and
adjacent low severity random cracking.
Any crack with a mean width 19 mm or any crack
with a mean width 19 mm and adjacent moderate
to high severity random cracking.
28
RUTTING SHOVING
29
Bleeding

• Excess bituminous binder occurring on the
  pavement surface, usually found in the wheel
  paths. May range from a surface discolored
  relative to the remainder of the pavement, to a
  surface that is losing surface texture because of
  excess asphalt, to a condition where the
  aggregate may be obscured by excess asphalt
  possibly with a shiny, glass-like, reflective
  surface that may be tacky to the touch.

30
RAVELING
Wearing away of the pavement surface caused by
the dislodging of aggregate particles and loss of
asphalt binder. Raveling ranges from loss of
fines to loss of some coarse aggregate and
ultimately to a very rough and pitted
surface with obvious loss of aggregate.
31
Caltrans Maintenance Treatment Matrix

• MTAG
• Chapter 2
• Figure 3

32
(No Transcript)
33
Distress Types and Levels that can be addressed
by BWC

• Perform Visual Site Inspection.
• Identify types, quantity and levels of distress
• For example on a 2 lane highway (Route xxx from
  PM 0.0 to PM 10.8)with
• 10 Alligator B Cracking
• Minor Transverse Cracking
• An area of isolated base failure 1000 ft x 4 ft
• Heavy raveling and oxidation
• Rutting

34
DISTRESS AND APPLICATION CONSIDERATIONS
BWC is a viable application for treating
structurally sound, worn pavements
35
Other Application Considerations

• Traffic Control
• Safety
• Night Work
• Returns/Hand Work (NO SETBACKS)
• Turn Pockets
• Milling
• Job Quantities
• Prep Work Required
• Quick return to traffic- Reduced Work Zone Time
  (Workers Safety)
• Noise Reduction- Open/Gap Graded Mix
• Night Work- Min Temp 45º F (More working days)
• Reduced Backspray- Open/Gap Graded Mix
• High Volume Roadways- Faster Paving Process (Get
  In- Get Out)

36
Performance Expectations

• Life and Costing
• Improved skid resistance
• Reduced traffic noise
• Spray Reduction
• Improved ride quality (Smoothness)
• Preventive Maintenance Activities Recommended
• Future Considerations

37
Application Cost and Life Cycle Data (from
Handout)

• Expected Life and
• Cost Data from
• Strategy Selection
• Group

38
Skid Resistance
39
Skid Resistance
40
Spray Reduction
Greater visibility on BWC surface
Backspray from dense graded surface
41
Improved Ride Quality -(Smoothness)

• Minor ruts and depressions can be filled with BWC
  to improve ride quality

42
Noise Reduction Data
Data from Acentech Route 85 Noise Mitigation
Study Report No. 184 Dated January 1998 Note
OGAC was the designation for BWC in this study
43
Future Considerations

• The main method of failure is wear the surface
  oxidizes and is abraded
• Future PM applications may include
• Fog Seal
• Microsurfacing
• Additional BWC Application
• Cold in-Place Recycling
• Mill and Replace

44
Future Maintenance Activities Recommended

• Crack Sealing
• Patching
• Re-Striping

45
Design Considerations

• Mobilization
• Typical Materials Items
• Quantity Calculations
• Production Rates
• Roadway Widths
• Roadway Geometry
• Traffic Control
• Miscellaneous Items
• Sample Project

46
Mobilization

• Similar to Typical Asphalt Paving
• On-site Staging Required
• Area for Tanker and Distributor exchange
• Special Permitting - None

47
Typical Materials Items

• Asphalt Concrete Tons
• Use maximum lbs/SY for selected aggregate size
• 3/8 PMA OG or GG (9.5mm) 85 lbs/SY
• ½ PMA OG or GG (12.5mm) 100 lbs/SY
• 3/8 AR OG of GG (9.5mm) 85 lbs/SY
• Emulsion Tons
• Use 0.2 gallons/SY for emulsion application

48
Quantity Calculations

• Lane Mile (LM) (Centerline to Fog Line)
• 5280 ft x 12 ft 63,360 SF 7040 SY
• When calculating quantities, application should
  extend beyond fog line
• Shoulder quantities need to be calculated
  independently
• Shoulder application may vary from mainline
  application
• Typical Shoulder calculation
• 3 ft wide x 5280 ft length 15,840 SF 1760 SY
• Typical 2 Lane Roadway Calculation
• (2 x 7040) (2 x 1760) 17,600 SY

49
Quantity Calculations

• When calculating quantities for each application
  use highest application rate per SY for estimate
  purposes
• Example
• Specification 37-1.06 Spreading of screenings for
  chip seal application. Range is 12-20 lb per SY.
  Use 20 lb for estimating quantities

50
Example of Actual BWC Calculation

• Typical 2 Lane Roadway 1 mile long with 3 foot
  shoulders 17,600 SY
• 10 mile section of roadway 176,000 SY
• AC Tons for Type B (3/8)
• 176,000 SY X 95 lbs/SY / 2000 lb 8,360 Total AC
  Tons
• Emulsion Tons
• 176,000 x 0.2 GAL/SY / 240 Gal/Ton 147 Tons of
  Emulsion

51
Production Rates andPaving Days

• Production Rate
• Mainline Paving - 125 tons per hour
• Returns/Turnpockets - 40-50 tons per hour
• ( of Paving Days)
• Minimum 5 days to make cost effective

52
Roadway Geometry and Widths

• Urban
• Milling
• ¾ - 1 contour edge grind required to match curb
  and gutter and existing pavement
• Drainage
• Minimal water trapped against curb due to
  emulsion filling void structure and thin lift
• Less water intrusion to pavement interface due to
  emulsion membrane
• Rural
• Cross-slopes
• Shoulder
• Generally best used for Travel Lane with 1 foot
  beyond fog line
• For Grade differential greater than 2 from
  Mainline to Shoulder, the shoulder must be paved
  separately in order to maintain the grade
• Edge drop-off will be less than ¾ (consider
  bicycle traffic material can not be feather down
  lower then top size agg.)
• In Contrast to Section 39, the BWC process
  recommends that shoulders and turn-pockets be
  paved first and through lane last. (Note to RE
  file)
• Varying Width
• Typical Paving machine width 8-14 feet variable

53
Traffic Control

• Typical release to traffic 10-20 minutes behind
  paver
• Multi-lane highways, consider moving lane closure
• Two-lane roadways ½ to ¾ mile closure
• Thinner lift allows faster production
• Emulsion Membrane eliminates need for Tack Coat

54
Miscellaneous Items

• Edge grinding
• Crack seal hot applied min one month prior
• Patching - hot mix only, cold mix continues to
  rut
• Utilities Adjustments most likely necessary
• Loops may need to be replaced if doing edge
  grinding
• Dig Outs Prior to paving
• Signing and Striping

55
Sample Design Example

• Item codes
• Item descriptions
• Unit of measure

56
Item code

• Caltrans uses item codes along with estimated
  item quantities to develop project construction
  costs. An item code is a six digit code used to
  describe a specific item or activity in a
  project. For example, the item code 193118 is
  used for concrete backfill and the item code
  066074 is used for traffic control. Each item
  code has a unit of measure. Concrete backfill is
  measured in cubic meters and traffic control is a
  lump sum unit. The engineer must determine what
  work items and/or activities are expected in the
  project and develop estimated quantities for
  bidding purpose. Caltrans Standard Materials and
  Supplemental Work Item Codes can be found at the
  following web site
• http//i80.dot.ca.gov/hq/esc/oe/awards/item_code.
  

57
Example of Item Codes
58
Example of Item Codes required to place Polymer
Modified Open Graded 9.5 mm Mix Project in
District 1
59
Example of Item Codes required to place Polymer
Modified PG Graded Type B Project in District 5
60
Material Specifications

• Binders
• Polymer modified asphalt spec
• Rubberized Asphalt spec
• Aggregates
• Gradations
• Physical Properties
• Mix Design
• Emulsion Membrane
• Application
• Specifications

61
Material Overview

• Bonded Wearing Courses are constructed using
  polymer-modified binders or rubberized asphalt
  and gap graded or open graded aggregates in the
  HMA component which are placed directly on the
  polymer modified emulsion membrane.
• For a copy of the specification SSP 39-700
  contact Office of Pavement Preservation

62
Polymer Modified Binders
Maintenance Technical Advisory Guide Chapter 8
Page 2
63
Polymer Modified Binder Testing
Maintenance Technical Advisory Guide Chapter 8
Page 3
64
Rubberized Binders

• A paving asphalt blended with a crumb rubber
  modifier
• Shall conform to SSP 39-480

65
Aggregate Gradations with PMA

• Aggregate Gradations available for use with the
  GGB grades of Polymer Modified Asphalt.
• 9.5mm (3/8) Fine minimum application thickness
  of 5/8 (typically ¾ recommended).
• 9.5mm (3/8) Coarse - minimum application
  thickness of 3/4 (typically 1 recommended).
• 12.5mm (1/2) minimum application thickness of
  7/8 (typically 1.25 recommended).

66
12.5 mm Gradation Table for PMA Gap Graded
Maintenance Technical Advisory Guide Chapter 8
Page 4
67
9.5mm Coarse Gradation For PMA Gap Graded
Maintenance Technical Advisory Guide Chapter 8
Page 4
68
Aggregate Physical Properties Polymer Modified
Asphalt
Maintenance Technical Advisory Guide Chapter 8
Page 5
69
Aggregate for use with Rubberized Asphalt Concrete

• The aggregate for rubberized asphalt concrete
  (Type O) shall conform to the 9.5 mm maximum
  grading conforming to the provisions in Section
  39-2.02, "Aggregate," of the Standard
  Specifications.
• The aggregate for rubberized asphalt concrete
  (Type O) shall be lime treated in conformance
  with the ??

70
Gap Graded AR
71
Aggregate Physical Properties For Rubberized Gap
Graded Mix

• AGGREGATE
• The aggregate for Type G rubberized asphalt
  concrete shall conform to the following grading
  and shall meet the quality provisions specified
  for Type A asphalt concrete in Section 39-2.02,
  "Aggregate," of the Standard Specifications,
  except as follows
• A. California Test 211, Los Angeles Rattler loss
  at 500 revolutions shall be 40 percent maximum.
• B.California Test 205, Section D, definition of a
  crushed particle is revised as follows "A
  particle having 2 or more fresh mechanically
  fractured faces shall be considered a crushed
  particle."
• C.The swell and moisture vapor susceptibility
  requirements shall not apply.
• The symbol "X" in the following table is the
  gradation which the Contractor proposes to
  furnish for the specific sieve.

72
Open Graded Aggregate Gradations with AR or PMA
Ref Caltrans Standard Specifications 2006
Section 39 Page 282
73
Open Graded Aggregate Gradations with AR or PMA
Ref Caltrans Standard Specifications 2006
Section 39 Page 282
74
Mix Design for Polymer Modified

• The performance of a bonded wearing course
  depends on the quality of the materials and how
  they interact during application, rolling and
  after opening to traffic. The amount of polymer
  modified asphalt binder to be mixed with the
  aggregate for gap-graded polymer modified asphalt
  concrete shall be determined by the Contractor
  using Asphalt Institute MS 2 Table 6.1.

75
Mix Design for Polymer (cont)
Maintenance Technical Advisory Guide Chapter 8
Page 6
Note The optimum binder content is first
established so that the film thickness
requirement is met. This binder content shall
conform to the drain down and film stripping
requirements.
76
Rubberized Type O BWCMix Design

• The amount of asphalt-rubber binder to be mixed
  with the aggregate for rubberized asphalt
  concrete (Type O) shall be determined by
  California Test 368 with the following
  exceptions
• The aggregate shall be mixed with PG 64-10 paving
  asphalt and the optimum bitumen content shall be
  determined in conformance with the test
  procedure.
• The optimum binder content for rubberized asphalt
  concrete Type O shall then be determined using
  the following formula
• OBC2 (OBC1) x 1.20 where
• OBC1 Optimum bitumen content using Pg-64-10
  paving asphalt
• OBC2 Optimum bitumen content using
  asphalt-rubber binder

77
Rubberized Gap -GradedMix Design

• SCOTT METCALF TO SUPPLY!!!!!

78
Emulsion Membrane Application (Used with both
Polymer Modified and AR Mixes)

• The emulsion membrane is designed to give high
  flexibility and bonding in the range of climactic
  conditions in which bonded wearing courses are
  placed (see Section 2.2).
• Application rate is typically .20 gal/SY /- .05
  depending on existing conditions.
• The emulsion is designed to break rapidly after
  spraying to ensure that no water is trapped. The
  gap-graded nature of the mix allows water to
  escape, thus promoting breaking of the emulsion.

79
Emulsion Membrane Spec.
Maintenance Technical Advisory Guide Chapter 8
Page 6
80
End Project Design, Materials
SpecificationsBegin Construction Inspection
81
Construction and Inspection
Module 11-2

• From Maintenance Technical
• Advisory Guide (MTAG)

82
Topics to be covered

• Understand/Review Specifications
• Safety and Traffic Control
• SWPPP
• Surface Preparation
• Equipment Requirements
• Calibrations
• Approved Mix design
• Sampling and Testing
• Binder
• Mix
• Emulsion
• Mix Production and Handling
• Required Application Conditions
• Application of Materials
• Production Rates
• Roadway Geometry and Paving Widths
• Application Problems and Solutions

83
Understand/Review Specifications

• Review Construction Manual Chapter 4
• Section 94 emulsion (emulsion membrane)
• Section 39 Asphalt Concrete (mix and placement)
• Review RE file notes
• Project special provisions

84
Safety and Traffic Control

• Traffic control is required both for the safety
  of the traveling public and the personnel
  performing the work. It is also used to ensure
  the new surface is compacted and allowed to cool
  to below 70C (158F) prior to reopening the
  surface to traffic.
• Traffic control includes placing construction
  signs, construction cones and/or barricades, flag
  personnel, and pilot cars required to direct
  traffic clear of the maintenance operation.

85
Traffic Control

• Typical release to traffic 10-20 minutes behind
  paver
• Multi-lane highways, consider moving lane closure
• Two-lane roadways ½ to ¾ mile closure
• Thinner lift allows faster production
• Emulsion Membrane eliminates need for Tack Coat

86
OPENING TO TRAFFIC

• Traffic can be allowed onto the new surface once
  rolling is completed and the mix temperature has
  fallen below 70C (158F).
• Typically, no post sweeping is required unless
  the mix begins to ravel.

87
SWPPP

• Review the storm water requirements for the
  project. Any questions should be directed to the
  construction storm water coordinator.

88
Surface Preparation

• Cracks greater than 6 mm wide (1/4 in) should be
  filled or sealed prior to application
• The use of over-banding methods of crack sealing
  is not recommended for this treatment
• Manhole covers, drains, grates, catch basins, and
  other utility services must be covered prior to
  application with roofing paper or equivalent
• Any surface irregularities deeper than 25 mm (1
  in) should be filled with dense graded hot mix
  before applying the BWC.
• Prior to application, the pavement should be
  swept with a rotary broom equipped with metal or
  nylon broom stock.
• Grinding???

89
CRACK PREPARATION MATERIAL APPLICATION PROCESS

• Sterilize Weeds 3 weeks prior

• Remove Weeds

• Grind out weeds

• Blow out Cracks

• (If moisture exists) Heat Lance
• cracks to remove moisture

• Material Application

• Apply sealer in cracks

90
CRACK PREPARATION
91
Prep Work Needed
Results of not sealing joint
92
Minimum one month ahead of paving
93
Preparation

• Milled Joints
• Beware of Quarter Crown Issues
• transverse cuts should be 2X paving depth
• Consider hot-mix tapers

94
Roadway Cleanliness
95
Construction Entrance NotSwept Prior to BWC
Application
96
Miscellaneous Items

• Edge grinding
• Crack seal hot applied min one month prior
• Patching - hot mix only, cold mix continues to
  rut
• Utilities Adjustments ?
• Loops -
• Dig Outs Prior to paving
• Signing and Striping

97
Equipment Requirements

• The most significant requirement is that the
  binder application and hot mix spreading function
  are combined into a single unit.

HMA
Membrane
98
Spray PaverCalibration Procedure

• 1. Once proper nozzles sizes have been selected,
  make sure all nozzles are clean and working.
• 2. Measure pad width and length to the nearest
  0.1 of an inch and record.
• 3. Weigh calibration pads to the nearest 0.1g and
  record.
• 4. Place plastic container on balance. Either
  record the weight of the plastic container or
  zero out the weight of the plastic container.
• 5. Place calibration pads a minimum of 5 feet in
  front of the emulsion spray bar in the direction
  of travel. Use two calibration pads to get an
  average representative distribution. Place the
  second pad a minimum of 1 foot behind the first
  pad.
• 6. Make sure the emulsion pump and bar pressure
  is set to optimal manufactures operating range.

99
Spray PaverCalibration Procedure (Cont.)

• 7. Engage the paver in automatic mode and allow
  the paver to come up to full paving speed before
  passing over the calibration pads.
• 8. Once the spray bars has passed over the
  calibration pads, carefully fold the edges of the
  calibration pads towards the center and roll the
  pad up so no emulsion will be lost when picked
  up.
• 9. Bring the plastic container to the calibration
  pad and place the pad in the container.
• 10. Record weight of the calibration pads.
• 11. It will be necessary to clean the plastic
  container before the second calibration pad is
  weighed or the weight of the plastic container
  will have to be re-zeroed as emulsion from the
  first pad will increase the weight of the
  container.

100
Spray Bar Calculation Procedure
101
Spray Bar Calculation Sheet for Spray Paver
102
Spray Bar Shot Rate Calculation
103
Approved Mix Design
104
Sampling and Testing Required

• California Test 125 July 2002
• METHODS FOR SAMPLING HIGHWAY MATERIALS AND
  PRODUCTS USED IN THE ROADWAY STRUCTURAL SECTIONS
• ASPHALT CONCRETE
• Aggregates . . . Part 1, Sections 1-2
• Asphalt . . . . . Part 6, Sections 1-3
• Modified Asphalt Concrete . . . . Part 7, Section
  4
• BITUMINOUS SEAL
• Polymer Modified Asphalt Emulsion . Part 6,
  Section 4

105
Mix Production and Handling

• The only special requirements are that the mixing
  temperatures for a BWC shall not exceed 177C
  (351F)
• Storage time shall not exceed 12 hours. A drain
  down test should be performed to ensure binder
  does not drain out of the mixture.
• All mixing plants must be calibrated to
  California Test Method CT 109.
• BWC mixes may be treated with an anti-stripping
  agent or lime if required, but the District
  Materials Engineer must approve this.

106
Required Application Conditions

• May be applied on damp, but not wet, surfaces.
• Minimum air and pavement temperature requirements
  are 7C (45F) and rising, although it is
  recommended that the surface temperature be above
  15C (59F).
• No freezing conditions are allowed in the first
  24 hours, the emulsion-based tack coat requires
  about one day to fully cure.

107
Application of BWC - Emulsion

• The polymer modified emulsion membrane at a
  temperature between 40 and 85C (104 and 185F)
  at a rate of 0.6 to 1.2 liter/m2 (0.13 to 0.3
  gal/yd2).
• The application rate should be adjusted according
  to the surface being covered.

108
Application of BWC - HMA

• Good paving practice should always be followed
  when constructing a BWC. Windrowing and pick up
  machines are not allowed for constructing bonded
  wearing courses.
• Paving Depth
• 9.5mm (3/8) Fine minimum application thickness
  of 5/8 (typically ¾ recommended).
• 9.5mm (3/8) Coarse - minimum application
  thickness of 3/4 (typically 7/8 recommended).
• 12.5mm (1/2) minimum application thickness of
  7/8 (typically 1 recommended).

109
Application of BWC HMA

• The minimum delivery temperature for a BWC is
  135C (275F), with an upper temperature limit of
  177C (351F).
• Longitudinal joints should be straight or
  correctly aligned to the curvature of the
  roadway, and should occur only at the edge or
  center of a traffic lane and never in the wheel
  paths.
• At the start and finish of the work, the existing
  flexible pavement should be cut out to a depth of
  30 mm (1.2 in) and tapered back a distance of 3m
  (10 ft) to provide a key for the new surfacing.

110
Construction
Pictures from MTAG Bonded Wearing Course for
Pilot Projects pg 11
111
Construction
Rolling operation showing traffic control.
Trimming necessary. No overlap during
construction due to emulsion membrane.
112
Application

• A minimum of one steel drum tandem roller is
  required for compacting a BWC.
• Rollers must be operated in static mode only.
• Usually two passes using a 12 to 15 ton roller is
  sufficient to properly seat the aggregates.
• Rolling must be carried out before the
  temperature, at mid layer of the mix, falls below
  90C (194F).

113
Production Rates andPaving Days

• Production Rate
• Mainline Paving - 125 tons per hour
• Returns/Turnpockets - 40-50 tons per hour

114
Roadway Geometry and Widths

• Urban
• Milling
• ¾ - 1 contour edge grind required to match curb
  and gutter and existing pavement
• Drainage
• Minimal water trapped against curb due to
  emulsion filling void structure and thin lift
• Less water intrusion to pavement interface due to
  emulsion membrane
• Rural
• Cross-slopes
• Shoulder
• Generally best used for Travel Lane with 1 foot
  beyond fog line
• For Grade differential greater than 2 from
  Mainline to Shoulder, the shoulder must be paved
  separately in order to maintain the grade
• Edge drop-off will be less than ¾ (consider
  bicycle traffic material cant not be feather down
  lower then top size agg.)
• In Contrast to Section 39, the BWC process
  recommends that shoulders and turn-pockets be
  paved first and through lane last. (Note to RE
  file)
• Varying Width
• Typical Paving machine width 8-14 feet variable

115
Application Problems and Solutions
116
Application Problems and Solutions
117
Application Problems and Solutions
118
Application Problems and Solutions
119
Application Problems and Solutions