STEEL SLAG INSTEAD NATURAL AGGREGATE IN ASPHALT MIXTURE

摘要

Even though electric arc furnace (EAF) steel slag has been classified as non-hazardous waste by its physical and chemical characteristics, and is possible to be disposed of at provided disposal sites without danger to the environment, this is rarely applied, because the permanent disposal of steel slag is highly expensive and requires a great area, and the valuable ingredients of steel slag are lost forever.The purpose of this paper was to improve the management of this type of non-hazardous industrial waste. Alongside with reducing the area intended for its disposal and increasing the technological benefit of re-using waste material, the final results of these tests should ensure the economic profit of producers, as well as achieve a sociological-ecological benefit due to the reduction of expenditure of natural mineral aggregates, simultaneously enhancing the sustainable development policies in metallurgy.A part of this research examines the possibilities of using EAF slag in other industries, with a special focus on using the slag as substitute for natural mineral aggregates in the production of asphalt mixtures in road construction. The paper presents the results of testing physical and mechanical properties of EAF slag coming from the regular production of unalloyed carbon steel in CMC Sisak, Croatia with the application of prior processing encompassing cooling the liquid slag by air, as well as quenching by water, grinding, magnetic separation, fragmentation and granulometric fractioning for the purpose of its application in technologies of producing asphalt mixtures.Comparison of test results between specimens of water- and air-cooled EAF slag and natural aggregates used in asphalt mixtures on highways and other top-class traffic load roads has demonstrated that the examined slag has equally good physical and mechanical properties, while it is significantly better in terms of resistance to polishing.