Enhanced heat release and self-healing properties of steel slag filler based asphalt materials under microwave irradiation

This paper aims to study the application feasibility of steel slag filler (SSF) to replace limestone filler (LF) to enhance heat release and self-healing properties of asphalt mastics. LF and SSF were firstly mixed with pure bitumen separately by filler-bitumen volume ratios of 0.2, 0.4 and 0.6. Then heating rates and self-healing properties of different asphalt mastics under microwave irradiation were characterized. Finally, heating mechanism based on the electromagnetic parameters and structure features of filler was analyzed. Results demonstrate that the average heating rates of SSF based asphalt mastics with 0.2, 0.4, 0.6 filler-bitumen volume ratio are 35.89%, 51.22% and 62.83% higher than those of LF asphalt mastics. Moreover, healing indexes of SSF based asphalt mastic are 39.99%, 10.15% and 5.82% higher than those of LF asphalt mastic from the perspectives of complex modulus, fatigue life and dissipated energy. Due to higher electromagnetic parameters and porous structure, SSF based asphalt mastics could convert energy of microwave irradiation into more thermal energy than LF based asphalt mastics. (C) 2018 Elsevier Ltd. All rights reserved.