The Effect of Steel Slag Powder on HMA Stability

The goal of the study is to evaluate the improvements of the stability of the hot mix asphalt (HMA) after the addition of ground steel slag. Steel slag was grounded into finer 75µm particles at Bangladesh Road Research Laboratory (BRRL). Then the ground steel slag powder was added to asphalt binder for penetration and softening point tests. Three modified HMA mixes were prepared with 20%, 30% and 40% of steel slag powder and 2% of cement for the Marshall test with a control mix containing 2% of cement only. The Marshall stability result shows increased stability and decreased flow. Marshall stability reached to maximum at the level of 30% of steel slag powder. The flow values obtained showed a slightly decreasing pattern with the increase in steel slag. The density of the mixes slightly decreases with the increase of steel slag content in the asphalt binder. It was found that the ground steel slag has a negligible effect on air voids (Va), voids in mineral aggregate (VMA), and voids filled with asphalt (VFA). A designed mix was also achieved the best possible result for all parameters in this experiment setup. Ground steel slag can be used in HMA and asphalt pavement construction, which can result in reduced maintenance work and minimize the frequency of rehabilitation and contributes to economic and environmental development.