Characteristics and properties of asphalt mortar containing FO filler: Fid-Bau Portal

Characteristics and properties of asphalt mortar containing FO filler

Liu, Jianan / Wang, Zhenjun / Jia, Hongyao / Jing, Haosen / Chen, Hao / Zhou, Liang / Yuan, Linjian / Hoff, Inge

Highlights • FO can significantly improve the microwave sensitivity of asphalt mixes. • The microwave characteristics of FO are dominated by magnetic loss. • Microwave heating uniformity of mixture with FO has been significantly improved. • The high temperature flow of asphalt mortar is the essence of microwave healing.

Abstract As a preventive maintenance method, microwave self-healing is an effective method for early repairing small cracks in asphalt mixture, reducing maintenance costs and prolonging service life. However, asphalt mixtures containing aggregate-type wave-absorbing agents have a common problem of uneven heating. Asphalt mixture was prepared by partially replacing the limestone filler with ferroferric oxide (Fe3O4, FO), and the healing performance under microwave heating was studied. The rheological properties of asphalt mortars with FO and the fluidity of conventional asphalt mortars were studied by dynamic shear rheometer (DSR). Then, the magnetostatic properties and electromagnetic parameters of FO fillers were analyzed by vibrating sample magnetometer (VSM) and vector network analyzer (VNA). Finally, the semicircular bending (SCB) samples were studied by the breaking-microwave healing experiment. The results show that FO fillers have obvious ferromagnetism, and they mainly rely on magnetic loss for energy conversion. FO is beneficial to the improvement of high temperature rheological properties of asphalt mortar but not to low temperature rheological parameters; the replacement ratio of FO to limestone filler should not exceed 50%. The flow healing behavior of asphalt mortar is greatly affected by temperature, which is the fundamental reason for the self-healing of asphalt mixture. The heating efficiency of the asphalt mixture containing FO filler is significantly improved under microwave irradiation; the FO filler has a slightly negative effect on the initial strength of SCB samples but can significantly improve the healing rate after microwave.