A Look to the Future By: Pat Hughes, Dave Holt, and Ron Bumann

A Look to the Future

By: Pat Hughes,

Dave Holt, and

Ron Bumann

Pavement Selection

A brief look at the Proposed Changes to thePavement Selection Process

Pavement Selection refers to the process used by Mn/DOT to determine the surface type (asphalt or concrete) of major construction/reconstruction projects.

What is Pavement Selection?

History of Pavement Selection

• Mn/DOT has had a formal procedure since 1959• Procedures were reviewed by Task Forces in

1977, 1981-1982 & 1995• Revisions were made in 1983, 1995, 1997 and

2001.• Current Task Force was appointed by Douglas

Weiszhaar, Mn/DOT Deputy Commissioner/Chief Engineer on August 23, 2002. Charge was to “fully evaluate” the existing process.

Task Force Members• Mn/DOT Members

– Richard Stehr, Chair, Director of Engineering Services Division– Robert Winter, Director of District Operations Division– Patrick Hughes, District Engineer, Metro Division– Keith Shannon, Director of Office of Materials– Nelrae Succio, District Engineer, Rochester– Abby McKenzie, Director of Statewide Planning and Analysis Section– Joseph Meade, Manager of Pavement Engineering Section– David Van Deusen, Pavement Engineer

• Other Members– Jeff Blue, Waseca County Engineer– William Lohr, FHWA Division Pavement and Materials Engineer– David Levinson, University of Minnesota, Department of Civil Engineering– Mark Snyder, Executive Director, Concrete Paving Association of Minnesota– Richard Wolters, Executive Director, Minnesota Asphalt Pavement Association– Dave Holt, Executive Director, MAPA, Retired.

Short Term RecommendationsShort Term Recommendations

• Service Life– Current Process = 35 years

– Proposed = 50 years

• Discount Rate– Current Process = 4.5%

– Proposed = Use 5-year running average of the Federal Office of Management and Budget real interest rate on a 30-year Treasury Note (for 2003 the rate is 3.5%).

Short Term RecommendationsShort Term RecommendationsCategories

Rename the “Exempt” Category to the “District” Category for small projects (less than 2-miles long or 30,000 sq.yds). District will be required to do Life Cycle Cost Analysis but not held to the low cost option provided there is a good reason not to do so.

Unbonded concrete overlays will no longer be required to go through the Pavement Selection Process. They will be treated as a rehabilitation activity.

The Informal and Formal criteria will remain unchanged for the time being.

Informal Bituminous Informal Concrete

FormalProcess

Residual Value Current Process = Ignore Proposed = Credit the value of any remaining life for the

last rehabilitation.

Age

Pav

emen

t Q

ual

ity

Ind

ex

End of Analysis Period

ResidualValue


Current Process Concrete: Joint reseal in year 17.5 Bituminous: Overlay in year 20

Recommended Process Use realistic timing and activities, including

preventive maintenance.

Have different strategies for bituminous roads with Low –vs- High Equivalent Standard Axle Loads.


Activity Timing

Activity Timing:Bituminous Pavements, <= 7 Million BESALs

AGE ACTIVITY

0 Initial Construction

6 Seal Cracks

10 Surface Treatment

20 Mill & Overlay

23 Seal Cracks


35 Mill & Overlay

38 Seal Cracks


50 End of analysis period, no residual value

Activity Timing:Bituminous Pavements, > 7 Million BESALs

AGE ACTIVITY


7 Fill Cracks

15 Mill & Overlay

20 Fill Cracks

27 Mill & Overlay

32 Fill Cracks

40 Mill & Overlay

45 Fill Cracks

50 End of analysis period, no residual value

Activity Timing:Concrete Pavements

AGE ACTIVITY


17 Joint Reseal(some minor concrete pavement repair, partial depth)

27 Minor Concrete Pavement Repair(some full depth repairs)

40 Major Concrete Pavement Repair

50 End of analysis period (5-years of residual value)

Activity Costs will be based on the median cost of

actual project costs built over the last 10-years.

Reduce the median cost by 10% to account for

today’s use of better quality materials and

improved specifications.

Adjust the activity costs by the difference

between highway construction and general

inflation rate, currently +0.21%.

Cost will be updated every year.


Flexibility Current Process

If the District does not like the resulting low cost option they may request a meeting of the Pavement Selection Committee, although changes are extremely rare.

Recommended Process Omit the Pavement Selection Committee…any

variance from the low cost option must be approved by the Chief Engineer.

If an error is discovered or additional information becomes available that was not know initially, the district can request a new estimate.


Long Term RecommendationsLong Term Recommendations

Use of Recycled Materials– Investigate the feasibility of incorporating salvage

aggregate into the cost estimate.

Formal/Informal Process– Have all projects go through the formal process for a

period of time once the new design guide is implemented and establish new criteria.

Aggregate Haul Distance– Investigate the current process, as well as alternatives

such as average bid prices and regional costs.

Long Term RecommendationsLong Term RecommendationsUser Costs (currently not considered)

– Users costs, defined as user delay and increased vehicle operating costs incurred during the initial construction and subsequent maintenance & rehabilitation activities, will be calculated on projects over a 12-month period. Recommendations will then be made on how to incorporate them into the pavement selection process.

Pavement Design– Further discussions are needed after the new design guide is implemented to

see what the impact will be on the current standard designs used in pavement selection.

– Current Design – Based on historical performance

– Mechanistic Design – Based on mechanical properties of materials (stress/strain/deflection).

Any Questions ?

Thank You!

http://mnroad.dot.state.mn.us/

pavement/bituminous/

bituminous.asp

Documents

A Look to the Future By: Pat Hughes, Dave Holt, and Ron Bumann