Volume 39, Issue 6 (November 2011)
Laboratory Evaluation of Microwave Heating Method for Hot In-Place Recycling
Gradual increasing pavement distresses need an efficient heating method for hot in-place recycling or rehabilitation maintenance. Microwave radiation could provide a quick and environmentally friendly heating measure for field heating on asphalt pavement. A 2450 MHz microwave heater was applied to study its heating performance on a dense gradation asphalt mixture in the laboratory. Eight temperature sensors were embedded into each layer in the specialized wheel tracking mixture slab to study the temperature status during the microwave heating process. The heating uniformity, optimal heating depth, and water’s influence on heating performance are discussed in this paper. Most of the standard temperature deviations on each layer are less than 7°C a nd present a good uniformity of temperature distribution in the mixture. The proper heating depth is around 10 cm for the dense gradation mixture by the microwave heater in this research. The water on the pavement surface will decrease the heating effect of microwave radiation and should be removed before field rehabilitation.