AN ANALYSIS OF THE IMPACTS OF TEMPERATURE SEGREGATION ON HOT MIX ASPHALT

This research was conducted to produce a more realistic picture of how variables are created and dealt with during hot mix asphalt (HMA) paving construction. Several paving projects across the State of Nebraska have been visited where sensing devices were used to test how the selected variables contribute to temperature differentials. These variables include density, moisture content within the asphalt, material surface temperature, internal temperature, wind speed, haul time, and equipment type. Areas of high temperature differentials are identified using an infrared camera whose usefulness was initially confirmed with a penetrating thermometer. A non-nuclear density device was also used to record how the lower temperature asphalt density compares to the more consistent high temperature area. After all variables were recorded, the locations were marked digitally via a handheld global positioning system (GPS) to aid in locating points of interest for future site inspections in order to verify research findings. In addition to the location-based database system using Google Earth, an extensive database query system was built which contains all data collected and analyzed during the period of this study. These research findings indicate that previously assumed variables thought to contribute to decreased density due to temperature differentials, such as haul time and air temperature, have little impact on overall pavement quality. Data analysis results also indicate a significant correlation between material temperature differentials and premature distress one to three freeze thaw seasons after roadway construction. Advisor: Yong K. Ch