Abstract: With the accelerated development of China’s stainless steel industry，the stock of stainless steel slag pile increases year by year and is difficult to use. Using stainless steel slag to prepare cement filler is an effective way to absorb a large amount of it. In this paper，the composition of AOD slag was modified by adding fly ash，and the cementitious properties of cement filler prepared by fly ash modified AOD slag were studied. The results showed that after high temperature modification of AOD slag with fly ash，it could form glassy matter after water quenching and quenching. With the increase of fly ash content，the content of glassy matter in modified AOD slag increased. When the mixing ratio of fly ash reached 35 %，the modified AOD slag was glassy matter. The analysis of mechanical properties and Cr leaching concentration of cementitious material showed that when the content of modified AOD slag was 20 %, the 28 day compressive strength of composite cement cementitious material was 54.4 MPa, which met the standard of P.C 52.5 cement. The Cr leaching concentration decreased with the decrease of modified AOD slag content, which was lower than 0.15 mg/L. The modified AOD slag could be safely applied to the field of building materials to realize the resource utilization of waste.

Key words: AOD slag, fly ash, cementitious property, leaching of Cr