Characteristics of bonding behavior between basic oxygen furnace slag and asphalt binder

• Basic oxygen furnace slag was used as aggregates in asphalt mixture.
• Chemical components on BOF slag surface have vital influence on bonding strength.
• BOF is covered with hydration layer to provide better asphalt stripping resistance.
• BOF slag shows higher adhesive strength to asphalt binder than basalt and granite.

Basic Oxygen Furnace (BOF) slag is one of the steel slags, which are by-products in steel industry. Currently there is lack of effective ways to reuse it. It has caused various environmental issues such as water pollution, soil pollution and shortage of storage spaces. Therefore, research on using BOF slag as a novel aggregate in asphalt pavement has benefits both in environment and economics. The bonding behavior between slags and asphalt binder is one of the most important properties to ensure a durable BOF slag based asphalt pavement.In this research, the bonding behavior between BOF slag and asphalt binder was studied. X-ray diffraction (XRD) was first conducted to understand the physical and hydration characteristics of BOF slag. Modified boiling water test and self-designed tensile test were than used to quantify the bonding behavior. Moisture resistance of bonding behavior can be also investigated with modified boiling water test. The results of boiling water test indicated that the BOF slag, firmly coved with hydration products, has the potential to protect the asphalt binder from being stripped by boiling water. Self-designed tensile test result illustrated that BOF slag had better bonding strength than the values of basalt and granite aggregates.