Use of a Thermal Camera during Asphalt Pavement Construction

There is a growing concern that thermally segregated hot mix asphalt (HMA) pavements result in lower densities. A study reported herein was conducted to determine whether thermal segregation occurs during asphalt pavement construction in North Dakota. Thermal pictures were acquired from five ongoing asphalt pavement projects during the 2008 construction season, and from one of the projects, areas significantly colder than their surrounding pavement areas were found - observations from further analysis suggested paver operations as one possible cause of the cold areas. If thermal segregation is defined as the fresh HMA mat having an area 25 degrees F colder than adjacent areas. thermal segregation does occur during asphalt pavement construction in North Dakota. However, densities of the observed cold areas are unknown although many previous research efforts found that densities of cold mat areas tended to be lower than their surrounding higher temperature areas. Furthermore, no well-defined relationship thus far exists between temperature differential and pavement density. Therefore, further research is needed to determine threshold mat temperatures below which pavement density is significantly affected and to identify other variables affecting density. A tool could also be developed that can predict pavement density given mat surface temperatures and other influencing variables