IGGA and ACPA recently used drone technology to conduct infrared testing of diamond ground concrete and asphalt rubber surfaced pavements in the Phoenix area to evaluate if the asphalt rubber ever achieves a cooler temperature throughout the day.

Larry Scofield, P.E., IGGA’s Director of Engineering and ACPA’s Director of Pavement Innovation, organized and executed the project to evaluate two sections of the Phoenix freeway system. Utilizing drone technology allowed for the infrared imaging to be performed during live traffic and evaluate the impact of convection cooling from the moving vehicles. The study found that even with the cooling impact of the traffic, the asphalt rubber surface remained hotter than the concrete pavement throughout the course of the entire day. The asphalt was found to range from 2 to 6 °F hotter than the adjacent concrete pavement travel lanes throughout the day.

The higher temperatures of the asphalt rubber contribute to the urban heat island in the valley area. An MIT case study recently found that the Phoenix area freeway system could reduce over 2.7 million tons of CO2-eq emissions by having an exposed concrete surface. Mr. Scofield’s full report on the infrared drone testing can be found here.