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

Pavement Selection A brief look at the Proposed Changes to the Pavement 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, & 1995 Revisions were made in 1983, 1995, 1997 and Current Task Force was appointed by Douglas Weiszhaar, Mn/DOT Deputy Commissioner/Chief Engineer on August 23, 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 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 Recommendations Categories 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 Formal Process

Residual Value Current Process = Ignore Proposed = Credit the value of any remaining life for the last rehabilitation. Age Pavement Quality Index End of Analysis Period Residual Value Short Term Recommendations

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. Short Term Recommendations Activity Timing

Activity Timing: Bituminous Pavements, <= 7 Million BESALs AGEACTIVITY 0Initial Construction 6Seal Cracks 10Surface Treatment 20Mill & Overlay 23Seal Cracks 27Surface Treatment 35Mill & Overlay 38Seal Cracks 43Surface Treatment 50End of analysis period, no residual value

Activity Timing: Bituminous Pavements, > 7 Million BESALs AGEACTIVITY 0Initial Construction 7Fill Cracks 15Mill & Overlay 20Fill Cracks 27Mill & Overlay 32Fill Cracks 40Mill & Overlay 45Fill Cracks 50End of analysis period, no residual value

Activity Timing: Concrete Pavements AGEACTIVITY 0Initial Construction 17Joint Reseal (some minor concrete pavement repair, partial depth) 27Minor Concrete Pavement Repair (some full depth repairs) 40Major Concrete Pavement Repair 50End 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 todays 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. Short Term Recommendations

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. Short Term Recommendations

Long 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 Recommendations User 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 ?

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