LTPP Seasonal Asphalt Concrete (Ac) Pavement Temperature Models

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Abstract

SUPERPAVE binders are selected based on the lowest and highest pavement temperatures expected at a job. The original SUPERPAVE specifications were developed with limited data for validating the low-temperature algorithm for pavement temperatures. The 10WEJst air temperature was assumed for the lowest pavement temperature. In areas with extremely low temperatures, this conservative approach has led to the selection of more restrictive binder grades than may be necessary. These binder grades usually require that modifiers be added to the asphalt, which increases the cost of the project.

The initial round (Loop-1) of the Long Term Pavement Performance study's Seasonal Monitoring Program (LTPP-SMP) - the collection of pavement and air temperatures at 30 test sites throughout North America - was completed in 1995. The availability ofthese data makes it possible to evaluate and refine existing pavement temperature algorithms.

Two new temperature data bases that combine the SMP data with weather station data from the original SUPERPAVE binder specifications were developed under this study. These data bases are used as tools throughout the study to further refine the existing low- and high-temperature models.

This report proposes revisions to the Strategic Highway Research Program (SHRP) Performance Grading System for asphalt binder selection. Revised models for determining the low- and high-temperature component of SUPERPAVE performance-based binders are presented and compared with existing models and resulting performance grades.