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In 1999 the Minnesota Department of Transportation (Mn/DOT) joined the California, Texas, and Washington State Departments of Transportation in forming a research partnership. The partnership was named the State Pavement Technology Consortium (SPTC). The consortium was formed to share information on pavement practices including design, rehabilitation, decision-making, and research. Specific to research the consortium is concerned with how pavement orientated studies are identified, conducted, funded, and implemented. The main objective of this paper was to gather infrared temperature and density data on a number of Minnesota Hot Mix Asphalt (HMA) paving projects in the 2000 construction season to investigate the effects, if any, temperature segregation has on the paving process and the resulting pavement compaction. The second objective was to collect specific information related to the construction such as the type of mix, the equipment used in the construction process, and environmental conditions and the effects they may have on the paving process and the resulting pavement compaction. One of the main problems facing the asphalt paving industry is hot mix asphalt segregation. Segregation is generally put into two categories, one is aggregate segregation and the other is temperature segregation. In aggregate segregation there is a concentration of either coarse or fine material in some areas of the paved mat. These areas are often characterized by different surface textures from the surrounding material and can usually be seen by the naked eye. Temperature segregation is the isolated pockets of different temperatures created in the paving process. These areas may or may not produce irregularities in the mat that can be seen. Stroup-Gardiner and Brown (1) have come up with a more thorough definition of segregation: "Segregation is the lack of homogeneity in the hot mix asphalt constituents of the in-place mat of such a magnitude that there is a reasonable expectation of accelerated pavement distress(es)." Previous research from the Washington Department of Transportation (WSDOT), NCAT and others has suggested that there is a correlation between material segregation and temperature differentials created in the paving process. Temperature differentials greater than 25‘F can cause areas of cooler material not to be compacted to the same densities as the surrounding warmer material. These areas can exhibit poor structural and textural characteristics, poor performance and durability, and can have shorter life expectancy and higher maintenance costs. The identification of these temperature differentials is captured with the use of a thermal imaging infrared camera. All objects no matter their temperature emit radiation. Measuring this radiation emitted allows you to determine the temperature of any and all points in the viewing spectrum of the camera. The temperature segregation will show up as different colors representing areas of different temperature. After a maximum predetermined temperature differential has been exceeded additional testing and inspection can be preformed to determine the level of distress that may or may not be present.