Study on induction healing properties of OGFC asphalt mixture with high elasticity and high viscosity modifier

Induction healing is a promising preventive maintenance method of asphalt pavement, but the healing properties of Open-Graded Friction Course (OGFC) asphalt mixture with high elasticity and high viscosity modifier (HEV) were not clear. OGFC asphalt mixture used for induction heating was prepared by adding steel wool fibers and HEV. The effects of HEV and steel wool on the properties of OGFC mixture were studied. The particle loss resistance, water stability, porosity, induction heating and self-healing properties of OGFC-13 asphalt mixture with different steel wool contents were measured. The results showed that HEV slightly improved the properties of resistance to particle loss, fracture strength and water stability of OGFC-13 asphalt mixture, had little effect on the induction heating rate and porosity, but reduced the healing rate by 10%. The addition of steel wool to OGFC-13 can enhance the particle loss resistance, heating rate and healing effect, and the optimal dosage is 8% of the volume fraction of bituminous binder. The healing rate rose steadily as the heating temperature increased. At the optimal healing temperature of 110 ℃, healing depth ratios of the mixtures without and with HEV were 56.3% and 43%, respectively, and the fracture energy healing rates were 72.4% and 63.1%, both at a high healing level. The incorporation of steel fibers and HEV reduced the porosity and water permeability of OGFC very slightly, and the porosity and water permeability of OGFC did not change significantly after induction heating. It is concluded that induction heating has a potential to heal the cracks within OGFC mixture with HEV to prevent surface raveling which is the primary damage of OGFC.