Analysis of Temperature Data for the National Center for Asphalt Technology Test Track

Abstract

Several combinations of mix type, aggregate type, asphalt binder type, and layer thickness are in place at the National Center for Asphalt Technology (NCAT) test track. It was desirable to examine the effects these various combinations may have on temperatures within the pavement. The purpose of this study was to evaluate measured versus predicted temperatures, evaluate the effect of mix type on pavement temperature, and compare the effect of surface layer thickness on pavement temperatures. On the basis of temperature data from the NCAT test track, some of the general conclusions are that ( a) both the Strategic Highway Research Program (SHRP) and Long-Term Pavement Performance (LTPP) temperature models slightly underpredicted high pavement temperatures at 50% reliability and slightly overpredicted temperatures at 98% reliability and ( b) the low-temperature models for SHRP overpredicteded low pavement temperatures for both 50% and 98% reliability. The LTPP models were also overly conservative at 98% reliability. These results indicate that asphalt binders may not need to be as soft as specified in the Superpaver; performance grading system for low-temperature performance.