Effect of Jordanian Steel Blast Furnace Slag on Asphalt Concrete Hot Mixes

Significant quantities of slag are generated as waste materials or by-product from steel industries. They usually contain considerable quantities of metals. In this study, steel slag obtained from a steel factory in Jordan was used in Asphalt Concrete Hot Mixes (ACHM). Marshall specimens were prepared with 100% lime stone dense graded aggregates at 4.5, 5, 5.5 and 6% bitumen contents by weight of aggregate to serve as control specimens. Another set of Marshall specimens with 100% Steel Slag Aggregates (SSA) and another set with a combination of limestone and (SSA) were prepared using the same grading and bitumen contents. Test results showed a reduction in the Optimum Bitumen Content (OBC) and an increase in density and stability values for specimens prepared with 100% (SSA). A decrease in the flow, Percentage of air voids (Pav), and Voids in Mineral Aggregates (VMA) values - but in compliance with the recommended values by the Asphalt Institute- was observed in specimens prepared with 100% (SSA).