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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. 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.

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Plant mix overview

Plant Mix Overview

MDT Training Conference

Billings, Montana

March 1 & 2, 2006

Presented By:

Matt Strizich and Danny Hood

Volumetrics incentives
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

Ride specification incentives
Ride Specification Incentives

  • 0.39% in 2002

  • 1.51% in 2003

  • 0.9% +/- from 2004-2006

  • Percentage of total spent on PMS that year

Compaction issues
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

Quick notes
Quick Notes

  • Volumetrics and the Ride Specification are not included on all projects

  • All end-result specifications

Contractors are earning it
Contractors are Earning it!

  • MDT is paying 3-5% of PMS costs in incentives

  • Plant production has been slowed

  • Seeing quality compete with production


  • Present potential future changes

  • Provide reasoning behind changes

  • Share information from last year

  • Provide the opportunity to ask questions


  • Grade S & Grade D Commercial Specification Revisions

  • New ½” Grade S Policy

  • Ride Specification Revisions

  • Compaction Issues in 2005

  • Aggregate Surface Treatment Experiment

Mdt staff
MDT Staff

  • Construction Reviewers

  • Project Staff

  • Internal Audit


  • Montana Contractors Association (MCA)

  • Non-Uniformity Complaints

  • Claims

Specification change process
Specification Change Process

  • All specification revisions go through the Specification Section

  • Dan Smith and Ryan Antonovich

  • Defined process

  • Standards Committee coming soon

Change process
Change Process

  • Ensures thorough review

  • Reviewed by MDT staff and contractors

Plant mix specifications

Plant Mix Specifications

Grade S and Grade D Commercial

Grades of plant mix

Grade S



Grade D Commercial



Grades of Plant Mix

Why two versions
Why two versions?

  • Contract administration

  • Quality of the same grades of mix should be equal.

  • Testing and frequency of testing varies

Grade s
Grade S

  • Completely revised mix

  • Grade S has been successful

  • Moved to gyratory compactors

  • Bob Weber and Scott Barnes deserve the credit


  • 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

Grade d commercial
Grade D Commercial

  • Relatively new specification

  • Always used on “smaller projects”

  • Bill Fogarty leading the committee

Grade b
Grade B

  • Use for bike paths or other features not subject to heavy loading

  • Consider using Grade D or S with chip seals instead

Grade c
Grade C

  • No longer needed

  • Grade D Commercial should be used instead

Change process1
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

Grade s changes
Grade S Changes

  • Changes are minimal

  • Changes are the same for volumetrics and non-volumetrics versions

Mix designs
Mix Designs

  • 50 Gyration mixes have been eliminated

  • SHRP recommendation for low volume roads

  • Created issues with meeting Hamburg testing requirements

Release agents specification
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.

Release agents specification1
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.

  • Release agents justification
    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

    Release agents justification1
    Release Agents - Justification

    • Plant Mix quality

    • Employee safety

    • Environmental concerns


    • 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


    • 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

    Grade d commercial1
    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

    Grade d commercial2
    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.

    Grade d commercial3
    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.

    Grade d commercial4
    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

    Grade d commercial5
    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.

    Grade d commercial6
    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.

    F factor change
    “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

    Grade d commercial7
    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.

    Grade d commercial8
    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

    Grade d commercial non tested
    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.

    Contract administration tied projects
    Contract Administration – Tied Projects

    • Issue has been identified

    • Materials working with construction to develop guidance


    • Compaction Concerns

    • Reduced lift thicknesses

    • Lower overall cost

    October 2003 policy
    October 2003 Policy

    • ½” Required for all lifts less than 60 mm

    • Introduced in response to Grade S compaction concerns

    • Followed SHRP recommendations

    Revised policy april 2005
    Revised Policy – April 2005

    • Limited use of ½” Grade S to low volume roads

    • Reduced the overall use.

    January 2006 revision
    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

    Additional requirements
    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


    • 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”


    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

    ½” Facts

    Meeting agenda
    Meeting Agenda

    • Introduction

    • Project Background

    • Draft Revised Ride Specification

    • Discussion of Pay Adjustment Factors

    Project purpose
    Project Purpose

    • Review Current Specification

    • Compare with Current Literature

    • Compare with State-of-Practice

    • End Products

    Why is pavement roughness important
    Why Is Pavement Roughness Important?

    • Ride Quality

    • Impacts on Vehicle Maintenance

    Why is pavement roughness important1
    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

    Project background
    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.

    Revised documents
    Revised Documents

    • Profiler Operations Manual (POM)

      • Comprehensive

    • MT-422 Document

      • Summary of POM

    • QC/QA Plan

      • Emphasis on field activities

    • Draft Revised Ride Specification

    Profiler operations manual pom
    Profiler Operations Manual (POM)

    • Calibration of Equipment

      • Full Calibration Check of Laser Sensors

      • Calibration of Accelerometers

      • Bounce Test Profiling System

      • Calibration of DMI

    Full calibration check of laser sensors
    Full Calibration Check of Laser Sensors

    • Calibrated and sealed by Manufacturer

    Courtesy testing
    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

    Surface smoothness
    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

    Surface smoothness1
    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

    Surface smoothness2
    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

    Profiling test section
    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.

    Quality control report
    Quality Control Report


    • 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

    Quality control report1
    Quality Control Report

    Meets Criteria So Use Run 1…for Roughness Report

    Surface profile
    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

    Bump report
    Bump Report

    • Considered Other Methodologies

      • Profilograph Simulation,

      • Bumpfinder and Grinding Simulation

      • Localized Roughness (TEX-1001-S) Method

    • Current System is Satisfactory

    Bump report1
    Bump Report

    • Bump Report for only first error free profile run in each lane is presented to EPM

    • Defect locations should be physically verified

    File naming convention
    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

    File directory
    File Directory

    • Two Conventions

      • By Control Number

      • By Date



    Avg MDT Class I

    Avg MDT Class II

    Avg MDT Class III

    Avg MDT Class IV



    Class IV Target


    Class III Target

    Post-Pave IRI (in/mi)



    Class II Target


    Class I Target









    Post-Pave IRI (in/mi)

    Category 1
    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 < 110 in/mile

    • Maximum post-pave IRI should not be greater than 90 in/mi

    Category 2
    Category 2

    • Target IRI set at 55 to 60 in/mi

    • Single lift overlays with pre-pave IRI value ³ 110 in/mi and < 190 in/mi

    • Maximum post-pave IRI should not be greater than 95 in/mi

    High pre pave iri roadways
    High Pre-Pave IRI Roadways

    • Exception for roadways with pre-pave IRI >190 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


    • 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

    Avg MDT Class I

    Avg MDT Class II

    Avg MDT Class III

    Avg MDT Class IV



    Class IV Target


    Class III Target

    Post-Pave IRI (in/mi)


    Category 2 Target


    Class II Target

    Category 1 Target


    Class I Target









    Post-Pave IRI (in/mi)


    Avg Category 1

    Avg Category 2


    Category 2 Target


    Category 1 Target

    Post-Pave IRI (in/mi)










    Post-Pave IRI (in/mi)

    Testing acceptance
    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

    Economic comparison
    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

    Economic comparison1
    Economic Comparison

    • Incentive

      • Payment will be similar to current system

    • Disincentive

      • Penalty will be more rigorous than current system

    Why is pavement roughness important2
    Why Is Pavement Roughness Important?

    • Ride Quality

    • Impacts on Vehicle Maintenance

    • User Cost

    • Montana Residents

    • FHWA Performance Goals

    • National Trends

    Concluding remarks
    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



    Draft Revised Ride Specification

    What s the problem
    What’s the problem?

    • Extensive problems encountered during 2005

    • Did not appear to be one specific problem

    • Conditions varied between jobs

    Potential contributing factors
    Potential Contributing Factors

    • Binder problems

    • ½” PMS

    • Aggregate Surface Treatment

    • Aggregate Surfacing

    • Weather

    • Contractor Operations



    Compaction Issues – 2005

    Aggregate surface treatment

    Aggregate Surface Treatment

    Proposed Experimental Project

    What s wrong with mc 70
    What’s wrong with MC-70

    • High Volatile Organic Compounds or VOC’s

    • Past “prime” failures

    Purpose of surface treatment
    Purpose of Surface Treatment

    • Dust abatement

    • Surface preservation

    • Seal

    • Plant mix compaction aid

    Current practice

    Magnesium Chloride

    SS-1 or CSS-1

    Current Practice


    • Relatively inexpensive

    • Effective for dust abatement

    • Helps preserve the section in most cases

    • Assists with compaction in most cases


    • Affinity for water

    • Needs “fines” and PI in the gravel for optimum performance

    • Corrosion concerns

    New specification
    New Specification

    • Currently working on writing

    • Intend to allow more flexibility

    • Possibly allow alternate products

    Experimental project s
    Experimental Project(s)

    • Trying alternate emulsified asphalt products

    • Pugmilling SS-1 into the top lift of aggregate surfacing

    • Control sections


    • Try on 2 or 3 projects early in the season

    • Evaluate the constructability immediately

    • If successful, implement as soon as possible



    Aggregate Surface Treatments