Experimental and numerical investigation of magnetic converge effect of magnetically conductive asphalt mixture

Nowadays, although the technical bottleneck of the poor self-healing effect of the inductive healing asphalt mixture (IHAM) caused by uneven temperature distribution in the lower part has been found, it has not been properly solved until now. Given that, this paper innovatively proposes to design the magnetically conductive asphalt mixture (MCAM) containing waste ferrites, and use its magnetic converge effect to improve the temperature field distribution of the lower part of the IHAM. Firstly, four kinds of MCAMs were designed based on the magnetic circuit model. Then the magnetic permeability tests, volumetric and mechanical performance tests of the MCAMs were conducted. Finally, the 2D electro-magneto-thermal coupling model of the MCAM composite IHAM at different heating frequencies and power was established. Test results show that the relative magnetic permeability of the MCAM is close to 60 when all aggregates and fillers are substituted by waste ferrites. Further, simulation results show that MCAM's magnetic converge effect can guide and concentrate the magnetic field to greatly improve the temperature of the lower part of IHAM, and the higher the heating power or frequency, the better the temperature improvement effect of the lower part of the IHAM. Finally, the optimal scheme for substituting coarse aggregate with waste ferrites is recommended for MCAM preparation based on the simulation and experimental results.