Performance enhancement of asphalt patch repair with innovative heating strategy

Abstract

The advantage of controlled preheating of an excavated asphalt surface prior to hot-mix asphalt patch repair, referred to as ‘dynamic repair’, is presented in this paper. The heating effects are compared with traditional repair, referred to as ‘static repair’. Shear bond and immersion wheel tracking tests were performed to assess the quality of both types of repair. Pothole excavations were created in the laboratory environment. For the static repairs, a tack coat was applied at the interfaces of the excavation prior to laying the hot repair material. For the dynamic repairs, infrared heat was applied in heating–cooling cycles prior to filling the excavation with hot-mix material, without the use of a 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 the dynamic repairs was, respectively, 78·2% and 68·4% higher than that of the static repairs. The immersion wheel tracking test showed that the resistance to water-related damage of the dynamic repairs was higher than that of the static repairs. It is concluded that preheating a pothole excavation with infrared heat prior to filling and compaction increases the repair interface bonding strength and durability.