NYSDOT Pavement Models
Modeling Mechanistic Properties of Unbound Materials for New York State
The Cornell Local Roads Program is conducting research on the seasonal variation of unbound pavement materials properties in New York State. This project will increase the applicability of the seasonal pavement materials models that were developed for the New York State Department of Transportation (NYSDOT) in an earlier research project Seasonal Variations of In Situ Materials Properties.
The models from that project were designed to help NYSDOT implement the new AASHTO mechanistic-empirical pavement design guide (DARWin-ME™) while still being applicable with the existing NYSDOT Comprehensive Pavement Design Manual (CPDM). This project will expand on earlier research results, creating models of seasonal change in unbound (subbase and subgrade) layer moduli applicable across approximately 90 percent of the area of New York State.
Cornell Spring Thaw Predictor for Local Highway Agencies in New York StateNew York State suffers from freeze-thaw cycles in the spring that cause significant damage to local pavements. Across the United States, spring load restriction periods (SLR's) restrict traffic and impose weight limits during the thaw-weakening season in order to reduce damage and better preserve pavements.
Some of the common SLR methods that have been used to determine the critical periods when the pavement is weak are either too simple or too complicated. The use of fixed dates determined by weather data, or simply waiting until after thawing has started, leads to preventable damage. Other, more complicated methods, can be very accurate, but require a large amount of detailed data which can be hard to obtain.
Spring freeze-thaw periods change from year to year both by location within NYS, and in response to the composition of a pavement.
The CSTP tool uses the Cornell Pavement Frost Model (CPFM) as the engine behind the calculations used to predict freeze-thaw cycles in pavements. A 10-day spring thaw forecast using publically available temperature data allow for accurate predictions of thawing and gives users sufficient warning time to plan for, and implement SLRs.
Seasonal Maps Currently Available
Map. 1 Average number of days of thawing (1987-2016)
Map 2. New York State Last Thaw Day (1986-2016)
Map 3. Average depth of frost 1987-2016
Map 4. Lifespan of low-volume pavement due to differences in climate in New York State