This project will be divided into 2 phases.
In Phase 1 the researchers will:
Conduct a literature review to summarize existing long-life
pavement design methodologies and research.
Summarize documented long-life flexible pavements within and
outside the US. The summary will include
identifying the pavement structure, materials used, performance history,
traffic data and climatic data.
Perform a series of site visits to long-life flexible
pavements. This will include a scanning
tour type visit to at least 6 States.
The actual locations will be based on the literature survey completed in
Step a, and identification of long-life pavements in Step b. The site visits
will provide detailed project information and performance history that will be
used to better document the range of pavement thicknesses that are providing
long life, as well as their engineering properties for a range of traffic
loadings and environments.
Prepare an interim report documenting the findings from the
literature review and the field visits and a detailed work plan for conducting
phase 2 of the project.
Phase 2 the researchers will use the information collected in Phase 1 to provide
adjustments to current M-E based design procedures like the AASHTO MEPDG,
PerRoad, or similar programs for optimum pavement designs, and to the extent
possible quantify the benefits of improved engineered asphalt materials.
for consideration are:
Relationship of lab limiting strain to field limiting strain with
impact on overall pavement thickness using in-service pavements
Properties of newer, engineered asphalt materials in a flexible
pavement design procedure (i.e., high-modulus high binder, SMA).
the MEPDG and pavement performance prediction of in-service pavements (back-casting
procédures should apply to new construction and rehabilitation designs
It is anticipated a maximum pavement structure will be developed
to provide long-life. This structure
could be used as a cap for new construction designs or rehabilitation designs,
independent of the traffic loadings.
Long-life pavement structures will be recommended for various categories
of road use (i.e., interstate, primary, secondary, urban streets), subgrade
support and climate. A design catalog
for new construction and rehabilitation projects along with recommended paving
materials and specifications will be a deliverable. The framework for a long-life flexible
pavement design tool or recommended changes/modifications to the AASHTO MEPDG
will be a deliverable.
All the findings from Phases 1 and 2 will be included in the study’s
final report. Phase 1 report must be
completed and submitted to the project panel for review and approval prior to
initiating Phase 2.