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Plant Mix Overview

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Plant Mix Overview MDT Training Conference Billings, Montana March 1 & 2, 2006 Presented By: Matt Strizich and Danny Hood Recent Plant Mix Use Volumetrics Incentives ... – PowerPoint PPT presentation

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Title: Plant Mix Overview


1
Plant Mix Overview
  • MDT Training Conference
  • Billings, Montana
  • March 1 2, 2006

Presented By Matt Strizich and Danny Hood
2
Recent Plant Mix Use
3
Volumetrics Incentives
  • 1.45 million or 2.85 in 2005
  • 0.48 million or 3.16 so far in 2006
  • Percentage of total spent on PMS that year

4
Ride Specification Incentives
  • 0.39 in 2002
  • 1.51 in 2003
  • 0.9 /- from 2004-2006
  • Percentage of total spent on PMS that year

5
Compaction Statistics
6
Compaction Issues
  • Compaction incentives were 1.04 in 2003 and
    1.20 in 2004
  • Dropped to 0.34 in 2005
  • Have a net disincentive of 0.22 so far in 2006

7
Quick Notes
  • Volumetrics and the Ride Specification are not
    included on all projects
  • All end-result specifications

8
Contractors are Earning it!
  • MDT is paying 3-5 of PMS costs in incentives
  • Plant production has been slowed
  • Seeing quality compete with production

9
Purpose
  • Present potential future changes
  • Provide reasoning behind changes
  • Share information from last year
  • Provide the opportunity to ask questions

10
Topics
  • Grade S Grade D Commercial Specification
    Revisions
  • New ½ Grade S Policy
  • Ride Specification Revisions
  • Compaction Issues in 2005
  • Aggregate Surface Treatment Experiment

11
MDT Staff
  • Construction Reviewers
  • Project Staff
  • Internal Audit

12
Contractors
  • Montana Contractors Association (MCA)
  • Non-Uniformity Complaints
  • Claims

13
Specification Change Process
  • All specification revisions go through the
    Specification Section
  • Dan Smith and Ryan Antonovich
  • Defined process
  • Standards Committee coming soon

14
Change Process
  • Ensures thorough review
  • Reviewed by MDT staff and contractors

15
Plant Mix Specifications
  • Grade S and Grade D Commercial

16
Grades of Plant Mix
  • Grade S
  • Volumetrics
  • Non-Volumetrics
  • Grade D Commercial
  • Tested
  • Non-Tested

17
Why two versions?
  • Contract administration
  • Quality of the same grades of mix should be
    equal.
  • Testing and frequency of testing varies

18
Grade S
  • Completely revised mix
  • Grade S has been successful
  • Moved to gyratory compactors
  • Bob Weber and Scott Barnes deserve the credit

19
Volumetrics
  • Volumetrics is how MDT administers and controls
    the plant mix quality
  • True end result specification
  • Successfully encourages contracts to control
    their operations
  • Want quality to be able to compete with production

20
Grade D Commercial
  • Relatively new specification
  • Always used on smaller projects
  • Bill Fogarty leading the committee

21
Grade B
  • Use for bike paths or other features not subject
    to heavy loading
  • Consider using Grade D or S with chip seals
    instead

22
Grade C
  • No longer needed
  • Grade D Commercial should be used instead

23
Change Process
  • Plan to review specifications yearly
  • Will continue to see the same issues if they are
    not identified
  • Anyone can initiate change
  • People doing the work need to identify the issues
  • MDT Project staff
  • Contractors
  • Reviewers

24
Grade S Changes
  • Changes are minimal
  • Changes are the same for volumetrics and
    non-volumetrics versions

25
Mix Designs
  • 50 Gyration mixes have been eliminated
  • SHRP recommendation for low volume roads
  • Created issues with meeting Hamburg testing
    requirements

26
Release Agents Specification
  • a)                  Trucks. Remove trucks from
    service that leak fluids. When directed, cover
    each load with canvas or other approved material
    to protect the mix at Contractor expense. Do not
    use Diesel fuel as a truck bed release agent.
    Use a commercially manufactured release agent
    approved by the Project Manager.

27
Release Agents - Specification
  • b)                  Rollers. Furnish and use
    rollers that compact the plant mix to the
    specified density. Remove rollers that crush the
    paving aggregates or otherwise damage the plant
    mix and replace the damaged plant mix at
    contractor expense.
  • Cleaning Agents. Do not use diesel fuel as a
    cleaning agent or as a release agent for any
    paving equipment or operations. Use a
    commercially manufactured release agent approved
    by the Project Manager.

28
Release Agents - Justification
  • Expands the existing restriction on diesel fuel
    to all equipment
  • Need to be uniform in our enforcement.
  • Contractors will include additional cost in bids
  • Will eliminate having the issue every time paving
    starts

29
Release Agents - Justification
  • Plant Mix quality
  • Employee safety
  • Environmental concerns

30
Tack
  • The cost of SS-1 will be incidental to the cost
    of Plant Mix Surfacing
  • Includes tack between lifts of paving and for
    sealing rumble strips
  • Tack is still required in all instances it was
    previously used

31
Tack
  • SS-1 will still be a pay item for some uses
  • Aggregate surface treatment
  • Fog sealing
  • Reasons for change
  • The number of lifts is no longer specified
  • Low cost item

32
Grade D Commercial
  • Mostly Clarifications
  • Extensive revisions last year
  • Previously relied only on compaction to control
  • Not enough control so 5 penalties on specified
    properties was added

33
Grade D Commercial
  • Wording change
  • Material. Provide Grade D Commercial Plant Mix
    Bituminous Surfacing with the specified asphalt
    binder, 1.4 hydrated lime, and meeting
    Table 701-15A requirements. Use fillers or
    additives as necessary.

34
Grade D Commercial
  • Clarification
  • c) Sampling. Sample the PGAB meeting subsection
    402.03.2 (B). A sample is two one-pint (two 500
    ml) containers of PGAB. Sample fillers, hydrated
    lime, additives, aggregate treatment and tack in
    accordance with MT-601.

35
Grade D Commercial
  • Revised target air voids
  • Percent Air Voids
  • changed from 3-5 to 2-4
  • Do not want drier mixes
  • Cost of oil is included in the Grade D Commercial
    bid item

36
Grade D Commercial
  • Reweighing of vehicles is no longer mandatory
  • It should still be done in most cases
  • The Project Manager may randomly designate the
    re-weighing of loaded vehicles.

37
Grade D Commercial
  • Reduced the F factor from 12 to 6
  • a)   Acceptance. Rescind Subsection 401.03.12 (E)
    and replace with the following
  • Plant mix surfacing is evaluated for density on
    a lot-by-lot basis under Subsection105.03.2,
    except as noted in Subsection 401.03.12(B).
    Change the F factor for the Compaction element
    in Table 105-2 Table of Price Reduction Factors
    from 12 to 6 for plant mix furnished under this
    provision.

38
F Factor Change
  • Compaction is no longer the only measure for
    controlling quality
  • Want to be consistent with other mixes
  • Inflated prices due to haul
  • Too much risk for Contractors

39
Grade D Commercial
  • Wording clarification
  • A 5 percent price reduction (15 maximum), in the
    unit bid price for PMS Grade D Commercial will be
    applied for each test not meeting the Mix Design
    Stability, Flow, Percent Air Voids, Asphalt
    Binder Properties, Gradation, or Asphalt content
    specified. Price reductions will be assessed on
    the quantity of material represented by each
    failing sample. The quantity of material
    represented by each sample is the total tons of
    material produced divided by the total number of
    samples representing the material.

40
Grade D Commercial
  • The quantity of material represented by each
    sample is the total tons of material produced
    divided by the total number of samples
    representing the material.
  • Changed to help keep administration uniform
  • Fairer to the contractor

41
Grade D Commercial Non Tested
  • Many of the same changes as the tested version
  • Price reductions are only assessed for obviously
    defective material
  • Added the following Provide the Project Manager
    density testing results upon request.

42
Contract Administration Tied Projects
  • Issue has been identified
  • Materials working with construction to develop
    guidance

43
½ Grade S Policy
44
Why?
  • Compaction Concerns
  • Reduced lift thicknesses
  • Lower overall cost

45
October 2003 Policy
  • ½ Required for all lifts less than 60 mm
  • Introduced in response to Grade S compaction
    concerns
  • Followed SHRP recommendations

46
Revised Policy April 2005
  • Limited use of ½ Grade S to low volume roads
  • Reduced the overall use.

47
January 2006 Revision
  • Construction Memo
  • Requires the use of ¾ PMS whenever 0.15 ft or
    greater is required
  • Requires ½ Grade S only be used for overlays
  • Allows reduced overlay depths if ½ is used

48
Additional Requirements
  • ½ Grade S can only be used if
  • Ave. Rut 0.20 inches or less
  • Ave Ride 80 in/mile or less
  • An isolation lift is required
  • Surfacing Design must approve

49
Implementation
  • Surfacing Design will review existing design
    projects and make recommendations
  • Projects will not be changed from ¾ to ½ Grade
    S
  • Change orders will be considered Should not be
    no cost

50
½ Facts
  • ½ Gr. S is more difficult to compact
  • ½ Gr. S is more expensive
  • ½ Gr. S is equal to or better than ¾
    structurally

51
Ride Specification Revisions
52
Meeting Agenda
  • Introduction
  • Project Background
  • Draft Revised Ride Specification
  • Discussion of Pay Adjustment Factors

53
Project Purpose
  • Review Current Specification
  • Compare with Current Literature
  • Compare with State-of-Practice
  • End Products

54
Why Is Pavement Roughness Important?
  • Ride Quality
  • Impacts on Vehicle Maintenance

55
Why Is Pavement Roughness Important?
  • User Cost
  • WesTrack Experiment


Approx. 10 Drop in IRI
4.5 Increase in Fuel Efficiency Savings of
10,257 gal of fuel per 1,000,000 veh miles
56
Project Background
  • Montana Residents Survey in 1998
  • Attention resources in the following order
  • Winter maintenance
  • Surface smoothness
  • Highway striping, debris removal, highway
    signage, winter roadway information, roadway
    maintenance, rest stop maintenance
  • Etc.

57
Revised Documents
  • Profiler Operations Manual (POM)
  • Comprehensive
  • MT-422 Document
  • Summary of POM
  • QC/QA Plan
  • Emphasis on field activities
  • Draft Revised Ride Specification

58
Profiler Operations Manual (POM)
  • Calibration of Equipment
  • Full Calibration Check of Laser Sensors
  • Calibration of Accelerometers
  • Bounce Test Profiling System
  • Calibration of DMI

59
Full Calibration Check of Laser Sensors
  • Calibrated and sealed by Manufacturer

60
Courtesy Testing
  • At least 7 calendar day notice to EPM
  • MDT will provide once per project
  • Not less than 2 and not more than 3 miles of
    continuous pavement
  • Contractor interprets results

61
Surface Smoothness
  • All mainline travel lanes including climbing
    lanes, passing lanes and ramps that are 0.2 miles
    or longer
  • Bridge decks included only if paved as part of
    project

62
Surface Smoothness
  • Not evaluated
  • Climbing and passing lanes less than 0.2 miles
  • Turning lanes
  • Acceleration and deceleration lanes
  • Shoulders and gore areas
  • Road approaches

63
Surface Smoothness
  • Not evaluated
  • Horizontal curves 900 feet or less in centerline
    radius
  • Pavement within 50 feet of bridge decks (only for
    bridges not paved as part of project)
  • Pavement within 50 feet of approach slabs and
    terminal paving points of project

64
Profiling Test Section
  • Procedures
  • Minimum of Two Runs

Beginning of Project (BOP)
End of Project (EOP)
Exclude Area (e.g., Bridge) With F5 Key
Start of Data Collection With F3 Key
End of Data Collection With F3 Key
Approx. 500 ft.
Approx. 500 ft.
65
Quality Control Report
  • Acceptability
  • For each interval, the average IRI for each run
    is within 5.7 of the mean IRI for both runs
  • If a run has an interval that is outside the
    acceptable limit, additional runs (up to three)
    should be made on that lane

66
Quality Control Report
Interval Run 1 Run 2 Mean Avg-5.7 Avg5.7 Does Run 1 Meet Criteria? Does Run 2 Meet Criteria?
1 67 67 67 63 71 okay okay
2 72 72 72 68 76 okay okay
3 68 67 68 64 71 okay okay
4 57 57 57 54 60 okay okay
5 67 66 67 63 70 okay okay
6 61 62 62 58 65 okay okay
7 59 60 60 56 63 okay okay
Meets Criteria So Use Run 1for Roughness Report
67
Surface Profile
  • Correct surface profile defects that fail bump
    criteria
  • 0.40 inches in a distance of 25 feet
  • Correct surface profile defects
  • Milling and filling
  • Diamond grinding

68
Bump Report
  • Considered Other Methodologies
  • Profilograph Simulation,
  • Bumpfinder and Grinding Simulation
  • Localized Roughness (TEX-1001-S) Method
  • Current System is Satisfactory

69
Bump Report
  • Bump Report for only first error free profile run
    in each lane is presented to EPM
  • Defect locations should be physically verified

70
Expectations
  • MDT profiles finished surface
  • 2 times
  • One run is the run
  • Second run is for quality control
  • After QC activities and acceptance
  • Operator delivers IRI Report and Bump Report to
    EPM
  • Potential defects will be physically examined

71
File Naming Convention
  • 7 Characters
  • 1 to 4 is Control Number
  • 5 to 6 is Direction
  • 7 is Lane
  • Example

1022NBT Control Number 1022, northbound
direction, travel lane
72
File Directory
  • Two Conventions
  • By Control Number
  • By Date

D\1022 D\15JUL05
73
Current Ride Specification
Class Target (in/mi) Other Criteria Other Criteria Other Criteria
I 46-65 3 or more opportunities Pre-Pave IRI lt 140 in/mi 2 Opportunities Pre-Pave IRI lt90 in/mi Single Lift Overlay
II 55-75 Pre-Pave IRI ³ 140 in/mi 2 Opportunities Pre-Pave IRI gt90 in/mi and lt140 in/mi Single Opportunity
III 56-80 Pre-Pave IRI ³ 140 in/mi and lt190 in/mi Single Opportunity
IV 61-90 Pre-Pave IRI gt190 in/mi Single Opportunity
74
Data Set
Class Count Post-Pave IRI Avg (in/mi) Min IRI (in/mi) Maxi IRI (in/mi) Std Dev (in/mi)
I 63 50 38 66 7
II 13 51 44 58 4
III 2 46 45 47 1
IV 2 61 59 63 3
75
100
90
Class IV Target
80
Class III Target
Post-Pave IRI (in/mi)
70
60
Class II Target
50
Class I Target
40
40
50
60
70
80
90
100
Post-Pave IRI (in/mi)
76
Category 1
  • Target IRI set at 50 to 55 in/mi
  • Project with two or more opportunities to improve
    the ride
  • Single lift overlays with pre-pave IRI lt 110
    in/mile
  • Maximum post-pave IRI should not be greater than
    90 in/mi

77
Category 2
  • Target IRI set at 55 to 60 in/mi
  • Single lift overlays with pre-pave IRI value ³
    110 in/mi and lt 190 in/mi
  • Maximum post-pave IRI should not be greater than
    95 in/mi

78
High Pre-Pave IRI Roadways
  • Exception for roadways with pre-pave IRI gt190
    in/mi
  • Treat as Category 1
  • 2 or more opportunities
  • Other
  • Budget, functionality, etc.
  • Specify a maximum post-pave IRI NOT be more than
    50 of pre-pave IRI

79
Opportunities
  • Placing a gravel base or surfacing course
  • Placing plant mix bituminous base
  • Placing cement treated base
  • Placing pulverized plant mix surfacing
  • Milling
  • Cold recycling (milling and laydown)
  • Each full 0.15 ft increment of new plant mix
    surfacing

80
Data Set
Class Count Post-Pave IRI Avg (in/mi) Min IRI (in/mi) Maxi IRI (in/mi) Std Dev (in/mi)
I 63 50 38 66 7
II 13 51 44 58 4
III 2 46 45 47 1
IV 2 61 59 63 3
Cate gory Count Post-Pave IRI Avg (in/mi) Min IRI (in/mi) Maxi IRI (in/mi) Std Dev (in/mi)
1 73 51 38 66 7
2 7 51 47 58 5
81
100
90
Class IV Target
80
Class III Target
Post-Pave IRI (in/mi)
70
Category 2 Target
60
Class II Target
Category 1 Target
50
Class I Target
40
40
50
60
70
80
90
100
Post-Pave IRI (in/mi)
82
65
Avg Category 1
Avg Category 2
60
Category 2 Target
55
Category 1 Target
Post-Pave IRI (in/mi)
50
45
40
40
45
50
55
60
65
Post-Pave IRI (in/mi)
83
Current Pay Adjustment Factor
Class Actual IRI (in/mi) Pay Factor
I lt40 1.25
I 40-45 1.10
I 46-65 1.00
I gt65 0.80
II lt45 1.25
II 45-55 1.10
II 56-75 1.00
II gt75 0.80
III lt56 1.10
III 56-80 1.00
III gt80 0.90
IV lt61 1.10
IV 61-90 1.00
IV gt90 0.90
84
Pay Adjustment Factor Category 1
IRI (in/mi) Pay Adjustment Factor
lt 35 1.25
35 - 50 1.845 17/1000 IRI
50 lt IRI lt55 1.00
55 - 75 1.825 3/200 IRI
75 lt IRI lt90 0.70
gt 90 Corrective Action Required (Initially Assumed as a Zero Pay)
85
Pay Adjustment Factor Category 2
IRI (in/mi) Pay Adjustment Factor
lt 50 1.10
50 - 55 2.100 1/50 IRI
55 lt IRI lt60 1.00
60 - 95 1.343 1/175 IRI
gt 95 Corrective Action Required (Initially Assumed as a Zero Pay)
86
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88
Testing Acceptance
  • Prior to seal and cover
  • Performed with 3 working days of completion
  • Contractor must ensure entire finished lane width
    can be tested and not impeded
  • Test results within 2 working days

89
Economic Comparison
  • Compared current classification pay versus
    category pay
  • Evaluated a total of 53 lanes
  • Category 1 would have 47 lanes
  • Category 2 would have 6 lanes

90
Total for Category 1
91
Total for Category 2
92
Total Difference
Category Current System New System D of Current System
1 307,684 179,083 (128,601) 58
2 43,120 22,389 (20,731) 52
93
Incentive for Category 1
94
Incentive for Category 2
95
Incentive Difference
Category Current System New System D of Current System
1 362,072 301,494 (60,578) 83
2 43,120 22,389 (20,731) 52
96
Disincentive for Category 1
97
Disincentive Difference
Category Current System New System D of Current System
1 (54,388) (122,411) (68,022) 225
2 - - - -
98
Economic Impact Example
Control Number Direction Current Class Current Pay () Category New Pay () Post-Pave IRI (in/mi)
2945 EB I 8,407 1 9,393 43
2945 WB I 6,409 1 6,527 45
4821 NB II 8,096 2 4,226 47
4821 SB II 7,569 2 3,482 47
99
Economic Comparison
  • Incentive
  • Payment will be similar to current system
  • Disincentive
  • Penalty will be more rigorous than current system

100
Why Is Pavement Roughness Important?
  • Ride Quality
  • Impacts on Vehicle Maintenance
  • User Cost
  • Montana Residents
  • FHWA Performance Goals
  • National Trends

101
Concluding Remarks
  • Held a seminar for contractors
  • Complete Final Report
  • Address Comments
  • Finalize MDT Ride Specification Document
  • First training session Spring 2006
  • Implementation June 2006

102
Questions
  • Draft Revised Ride Specification

103
Compaction Issues 2005
104
Whats the problem?
  • Extensive problems encountered during 2005
  • Did not appear to be one specific problem
  • Conditions varied between jobs

105
Glendive Area Projects
106
Potential Contributing Factors
  • Binder problems
  • ½ PMS
  • Aggregate Surface Treatment
  • Aggregate Surfacing
  • Weather
  • Contractor Operations

107
Questions?
  • Compaction Issues 2005

108
Aggregate Surface Treatment
  • Proposed Experimental Project

109
Whats wrong with MC-70
  • High Volatile Organic Compounds or VOCs
  • Past prime failures

110
Purpose of Surface Treatment
  • Dust abatement
  • Surface preservation
  • Seal
  • Plant mix compaction aid

111
Current Practice
  • Magnesium Chloride
  • SS-1 or CSS-1

112
Advantages
  • Relatively inexpensive
  • Effective for dust abatement
  • Helps preserve the section in most cases
  • Assists with compaction in most cases

113
Disadvantages
  • Affinity for water
  • Needs fines and PI in the gravel for optimum
    performance
  • Corrosion concerns

114
New Specification
  • Currently working on writing
  • Intend to allow more flexibility
  • Possibly allow alternate products

115
Experimental Project(s)
  • Trying alternate emulsified asphalt products
  • Pugmilling SS-1 into the top lift of aggregate
    surfacing
  • Control sections

116
Objectives
  • Try on 2 or 3 projects early in the season
  • Evaluate the constructability immediately
  • If successful, implement as soon as possible

117
Questions?
  • Aggregate Surface Treatments
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