Thermal influence in the performance of static and dynamic hot mix asphalt pothole repairs

The advantage of controlled preheating of excavated asphalt surface prior to hot mix asphalt patch repair, referred as “dynamic repair”, is presented in this paper. The heating effects are compared against traditional hot mix repair, referred as “static repair”. Shear bond tests and immersion wheel tracking tests were performed to asses the quality of both types of repair. Pothole excavations were created in the laboratory environment. For static repairs, tack coat was applied at the interfaces of the excavation, prior to laying hot repair material. For dynamic repairs, infrared heat was applied in heating-cooling cycles prior to filling the excavation with hot mix material, without use of tack coat. Heat was applied using an experimental infrared heater set at 6.6 kW with a 230 mm offset from the excavation. The results showed that the shear strength at the bottom and vertical interfaces of dynamic repairs was 78.2% and 68.4% higher respectively than that of static repairs. The immersion wheel tracking test showed that the resistance to water-related damage of dynamic repairs was higher than that of static repairs. It has been concluded that preheating a pothole excavation with infrared heat prior to filling and compaction increases the repair interface bonding strength and durability.