title: Environmental impacts of asphalt mixes with electric arc furnace steel slag.
abstract: Electric arc furnace (EAF) steel slag can be used as an alternative high-quality material in road construction. Although asphalts with slag aggregates have been recognized as environmentally acceptable, there is a lack of data concerning the potential leaching of toxic Cr(VI) due to the highly alkaline media of EAF slag. Leaching of selected water extractable metals from slag indicated elevated concentrations of total chromium and Cr(VI). To estimate the environmental impacts of asphalt mixes with slag, leachability tests based on diffusion were performed using pure water and salt water as leaching agents. Compact and ground asphalt composites with natural aggregates, and asphalt composites in which the natural aggregates were completely replaced by slag were prepared. The concentrations of total chromium and Cr(VI) were determined in leachates over a time period of 6 mo. After 1 and 6 mo, the concentrations of some other metals were also determined in the leachates. The results indicated that chromium in leachates from asphalt composites with the addition of slag was present almost solely in its hexavalent form. However, the concentrations were very low (below 25 μg L) and did not represent an environmental burden. The leaching of other metals from asphalt composites with the addition of slag was negligible. Therefore, the investigated EAF slag can be considered as environmentally safe substitute for natural aggregates in asphalt mixes.
authors.affiliation: Department of Environmental Sciences, Jozef Stefan Institute, Ljubljana, Slovenia. radmila.milacic@ijs.si
authors.forename: Radmila
authors.initials: R
authors.lastname: Milačič
authors.forename: Tea
authors.initials: T
authors.lastname: Zuliani
authors.forename: Tina
authors.initials: T
authors.lastname: Oblak
authors.forename: Ana
authors.initials: A
authors.lastname: Mladenovič
authors.forename: Janez Šč
authors.initials: JŠ
authors.lastname: Ančar
mesh_terms: D002857:Chromium / Q000032:analysis / Q000737:chemistry; D003252:Construction Materials / Q000032:analysis; D004784:Environmental Monitoring; D006838:Hydrocarbons / Q000032:analysis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000032:analysis*; D013232:Steel / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D006838:Hydrocarbons; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D002857:Chromium; D013232:Steel; C006647:asphalt