Figure 19: Temperature segregation identified with thermal imaging [47

temperature differential [47]. These cold spots can be seen in Figure 19 where they identified areas of temperature segregation at 212°F (100°C) where the surrounding areas were 285°F (140°C).

Figure 19: Temperature segregation identified with thermal imaging [47]

Temperature segregation has numerous causes but generally it is a result of differential cooling within the asphalt. There are many typical construction activities that can result in temperature differentials [48]: • Asphalt mix cooling during transport • Lack of remixing before paving • Night paving with an ambient temperature lower than 70°F • Haul times of greater than 70 minutes • Accidental asphalt mix discharge on the base that is later paved over • Incidents that lead to paver stoppage

Temperature segregation can occur in transport through loss of heat through the truck sides and insulating cover [46,48,49]. The combination of improper insulation, long haul time, and low ambient temperature can cause significant temperature differences in transport [49]. Generally, any exposure to different environments for portions of the asphalt mix can cause

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