Effect of EAF carbon steel slag grain size on the properties of asphalt concrete

In this study, EAF carbon steel slag was divided into four range of grain sizes (25 ~ 12.5 mm, 12.5 ~ 4.75 mm, 4.75 ~ 0.6 mm, and 0.6 ~ 0.075 mm), and the replacement amount of EAF carbon steel slag was fixed at 24%. Asphalt concrete specimens with different grain sizes of EAF carbon steel slag were prepared, and the effects of different grain sizes of EAF carbon steel slag on the engineering properties of asphalt concrete were investigated by resilience modulus, static creep, indirect tensile strength, residual strength of water immersion, Cantabro test, boiling, thermal image analysis, and thermal conductivity tests. The results of the study show that different grain sizes of EAF carbon steel slag have a significant effect on the mechanical properties of asphalt concrete, the best resilience modulus can be achieved by replacing the grain size with 25 ~ 12.5 mm or 12.5 ~ 4.75 mm EAF carbon steel slag. The replacement of 0.6 ~ 0.075 mm and 4.75 ~ 0.6 mm EAF carbon steel slag has better effect on the indirect tensile strength and stripping resistance of asphalt concrete than 25 ~ 12.5 mm and 12.5 ~ 4.75 mm, with 0.6 ~ 0.075 mm being the best. From the thermal image analysis results, it was found that different grain sizes of EAF carbon steel slag had no significant effect on the temperature uniformity of asphalt concrete, but replacing EAF carbon steel slag with grain sizes of 0.6 ~ 0.07 mm significantly improves the thermal diffusivity rate of asphalt concrete. © 2022, Chinese Institute of Civil and Hydraulic Engineering. All right reserved.