Laboratory investigation of basic oxygen furnace slag for substitution of aggregate in porous asphalt mixture

The purpose of this study is to investigate the mixture performance and the sound absorption characteristic of porous asphalt mixture with different percentages of basic oxygen furnace (BOF) slag. Mixtures made with 0%, 25%, 50%, 75% and 100% BOF slag by volume as a coarse aggregate substitution were considered. The packing grading mixture design method (PGMDM) was applied in the design of porous asphalt. The test results show that BOF slag has high specific gravity, high absorption, high angularity, low L.A. abrasion, and low soundness compared with crushed stone (CS). The mixtures with BOF slag enhance skid resistance, moisture susceptibility, rutting resistance and sound absorption. Scanning electron microscope (SEM) used for micrograph demonstration shows that the rough surface pores and surface texture of BOF slag have a strong bond characteristic and an excellent interfacial zone for asphalt binder. The Duncan’s multiple range test results indicate that the BOF slag substitution percentage is significantly different in terms of mixture performance. The CS completely replaced by the BOF slag for porous asphalt mixture is recommended to obtain the optimum performance.