Title: Plant Mix Overview
1Plant Mix Overview
- MDT Training Conference
- Billings, Montana
- March 1 2, 2006
Presented By Matt Strizich and Danny Hood
2Recent Plant Mix Use
3Volumetrics 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
4Ride Specification Incentives
- 0.39 in 2002
- 1.51 in 2003
- 0.9 /- from 2004-2006
- Percentage of total spent on PMS that year
5Compaction Statistics
6Compaction 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
7Quick Notes
- Volumetrics and the Ride Specification are not
included on all projects - All end-result specifications
8Contractors are Earning it!
- MDT is paying 3-5 of PMS costs in incentives
- Plant production has been slowed
- Seeing quality compete with production
9Purpose
- Present potential future changes
- Provide reasoning behind changes
- Share information from last year
- Provide the opportunity to ask questions
10Topics
- Grade S Grade D Commercial Specification
Revisions - New ½ Grade S Policy
- Ride Specification Revisions
- Compaction Issues in 2005
- Aggregate Surface Treatment Experiment
11MDT Staff
- Construction Reviewers
- Project Staff
- Internal Audit
12Contractors
- Montana Contractors Association (MCA)
- Non-Uniformity Complaints
- Claims
13Specification Change Process
- All specification revisions go through the
Specification Section - Dan Smith and Ryan Antonovich
- Defined process
- Standards Committee coming soon
14Change Process
- Ensures thorough review
- Reviewed by MDT staff and contractors
15Plant Mix Specifications
- Grade S and Grade D Commercial
16Grades of Plant Mix
- Grade S
- Volumetrics
- Non-Volumetrics
- Grade D Commercial
- Tested
- Non-Tested
17Why two versions?
- Contract administration
- Quality of the same grades of mix should be
equal. - Testing and frequency of testing varies
18Grade S
- Completely revised mix
- Grade S has been successful
- Moved to gyratory compactors
- Bob Weber and Scott Barnes deserve the credit
19Volumetrics
- 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
20Grade D Commercial
- Relatively new specification
- Always used on smaller projects
- Bill Fogarty leading the committee
21Grade B
- Use for bike paths or other features not subject
to heavy loading - Consider using Grade D or S with chip seals
instead
22Grade C
- No longer needed
- Grade D Commercial should be used instead
23Change 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
24Grade S Changes
- Changes are minimal
- Changes are the same for volumetrics and
non-volumetrics versions
25Mix Designs
- 50 Gyration mixes have been eliminated
- SHRP recommendation for low volume roads
- Created issues with meeting Hamburg testing
requirements
26Release 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.
27Release 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.
28Release 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
29Release Agents - Justification
- Plant Mix quality
- Employee safety
- Environmental concerns
30Tack
- 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
31Tack
- 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
32Grade 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
33Grade 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.
34Grade 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.
35Grade 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
36Grade 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.
37Grade 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.
38F 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
39Grade 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.
40Grade 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
41Grade 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.
42Contract Administration Tied Projects
- Issue has been identified
- Materials working with construction to develop
guidance
43½ Grade S Policy
44Why?
- Compaction Concerns
- Reduced lift thicknesses
- Lower overall cost
45October 2003 Policy
- ½ Required for all lifts less than 60 mm
- Introduced in response to Grade S compaction
concerns - Followed SHRP recommendations
46Revised Policy April 2005
- Limited use of ½ Grade S to low volume roads
- Reduced the overall use.
47January 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
48Additional 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
49Implementation
- 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
50½ 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
51Ride Specification Revisions
52Meeting Agenda
- Introduction
- Project Background
- Draft Revised Ride Specification
- Discussion of Pay Adjustment Factors
53Project Purpose
- Review Current Specification
- Compare with Current Literature
- Compare with State-of-Practice
- End Products
54Why Is Pavement Roughness Important?
- Ride Quality
- Impacts on Vehicle Maintenance
55Why 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
56Project 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.
57Revised Documents
- Profiler Operations Manual (POM)
- Comprehensive
- MT-422 Document
- Summary of POM
- QC/QA Plan
- Emphasis on field activities
- Draft Revised Ride Specification
58Profiler Operations Manual (POM)
- Calibration of Equipment
- Full Calibration Check of Laser Sensors
- Calibration of Accelerometers
- Bounce Test Profiling System
- Calibration of DMI
59Full Calibration Check of Laser Sensors
- Calibrated and sealed by Manufacturer
60Courtesy 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
61Surface 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
62Surface Smoothness
- Not evaluated
- Climbing and passing lanes less than 0.2 miles
- Turning lanes
- Acceleration and deceleration lanes
- Shoulders and gore areas
- Road approaches
63Surface 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
64Profiling 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.
65Quality 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
66Quality 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
67Surface 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
68Bump Report
- Considered Other Methodologies
- Profilograph Simulation,
- Bumpfinder and Grinding Simulation
- Localized Roughness (TEX-1001-S) Method
- Current System is Satisfactory
69Bump Report
- Bump Report for only first error free profile run
in each lane is presented to EPM - Defect locations should be physically verified
70Expectations
- 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
71File 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
72File Directory
- Two Conventions
- By Control Number
- By Date
D\1022 D\15JUL05
73Current 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
74Data 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
75100
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)
76Category 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
77Category 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
78High 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
79Opportunities
- 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
80Data 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
81100
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)
8265
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)
83Current 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
84Pay 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)
85Pay 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)
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88Testing 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
89Economic 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
90Total for Category 1
91Total for Category 2
92Total 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
93Incentive for Category 1
94Incentive for Category 2
95Incentive 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
96Disincentive for Category 1
97Disincentive Difference
Category Current System New System D of Current System
1 (54,388) (122,411) (68,022) 225
2 - - - -
98Economic 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
99Economic Comparison
- Incentive
- Payment will be similar to current system
- Disincentive
- Penalty will be more rigorous than current system
100Why Is Pavement Roughness Important?
- Ride Quality
- Impacts on Vehicle Maintenance
- User Cost
- Montana Residents
- FHWA Performance Goals
- National Trends
101Concluding Remarks
- Held a seminar for contractors
- Complete Final Report
- Address Comments
- Finalize MDT Ride Specification Document
- First training session Spring 2006
- Implementation June 2006
102Questions
- Draft Revised Ride Specification
103Compaction Issues 2005
104Whats the problem?
- Extensive problems encountered during 2005
- Did not appear to be one specific problem
- Conditions varied between jobs
105Glendive Area Projects
106Potential Contributing Factors
- Binder problems
- ½ PMS
- Aggregate Surface Treatment
- Aggregate Surfacing
- Weather
- Contractor Operations
107Questions?
108Aggregate Surface Treatment
- Proposed Experimental Project
109Whats wrong with MC-70
- High Volatile Organic Compounds or VOCs
- Past prime failures
110Purpose of Surface Treatment
- Dust abatement
- Surface preservation
- Seal
- Plant mix compaction aid
111Current Practice
112Advantages
- Relatively inexpensive
- Effective for dust abatement
- Helps preserve the section in most cases
- Assists with compaction in most cases
113Disadvantages
- Affinity for water
- Needs fines and PI in the gravel for optimum
performance - Corrosion concerns
114New Specification
- Currently working on writing
- Intend to allow more flexibility
- Possibly allow alternate products
115Experimental Project(s)
- Trying alternate emulsified asphalt products
- Pugmilling SS-1 into the top lift of aggregate
surfacing - Control sections
116Objectives
- Try on 2 or 3 projects early in the season
- Evaluate the constructability immediately
- If successful, implement as soon as possible
117Questions?
- Aggregate Surface Treatments