Anti-stripping agent for asphalt mixture including refined slowly-cooled slag, method for preparing the same, asphalt mixture including the same and method for preparing the same

An anti-stripping agent for an asphalt mixture comprising a refined iron and steel slag, wherein the refined iron and steel slag comprises 55 to 65 mass % of CaO, 5 to 10 mass % of SiO2, 1 to 5 mass % of Al2O3, and 1 to 5 mass % of MgO,

• wherein the anti-stripping agent has a water content of from 0.4 to 0.6 wt % uniformly distributed throughout,
• wherein the refined iron and steel slag is in the form of a powder of particles of less than 70 mm in diameter, and
• wherein the anti-stripping agent exhibits plasticity index of 6 or less, flow index 50% or less, swelling 3% or less, and anti-stripping performance of ¼ or less.