STEEL SLAG APPLICATION IN CROATIAN ASPHALT MIXTURE PRODUCTION Tahir SOFILIĆ 1 , Alenka RASTOVČAN-MIOČ 2 , Mario ĆOSIĆ 1 , Vesna MERLE 1 , Boro MIOČ 3 , Una SOFILIĆ 4 1 CMC Sisak d.o.o. Braće Kavurić 12, 44010 Sisak, Croatia 2 University of Zagreb, Faculty of Metallurgy Aleja narodnih heroja 3, 44010 Sisak, Croatia 3 Sisak projekti d.o.o. Rimska ulica 26, 44000 Sisak, Croatia 4 Tina Ujevića 25, 44010 Sisak, Croatia Abstract This paper demonstrates the results of examines the possibilities of using steel 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. Within the framework of this work, test fields have recently been constructed. The existing wearing course was replaced by an AC 11 type of asphalt, in one lane with conventional natural carbonate aggregate and in the other two lanes with slag aggregate from CMC Sisak d.o.o. (0/4, 4/8, 8/11). After construction of the test field using EAF slag aggregate it was found that no problems has been encountered in the designing of the mixture or in the placing of the asphalt in the test field. Keywords: steel slag; road construction; asphalt 1. INTRODUCTION Starting from the importance of mineral raw materials for the development of overall economy of the Republic of Croatia, with respect to producers' potentials and growing market needs, a systematic approach to researching alternative sources of these materials with the purpose of creating stable economic growth in the conditions of sustainable development is necessary. At the same time, having in mind that the national environmental strategy of the Republic of Croatia defines waste management as national priority with the so- called no-landfill concept, for the realization of which one should close the circle of avoiding the very creation of waste, reducing the quantity and harmfulness, recycling and reuse, some industrial waste materials have, thanks to their composition and structures, started being used as secondary raw materials in road construction in Croatia as well. Metallurgical slag is waste or by-product formed in metallurgical processes from impurities in the metals or ores being treated. The metallurgical slags are classified in two types: ferrous slag, including iron slag generated in blast furnace process and steel slags and non-ferrous slag generated by production non-ferrous metals (Cu, Zn, Pb, Ni,..). According to chemical composition, steelmaking slag is a complex matrix structure consisting primarily of oxides of calcium, iron, silicon, aluminum, magnesium, and manganese in complexes of calcium silicates, aluminosilicates and aluminoferite. In the past, the application of steel slag was not attractive because vast volumes of blast furnace slag were available. Steelmaking slag has been used commercially since at least the mid-19th century. It is currently used in all industrialized countries, wherever steel is produced. Beginning in the 20th century, many new uses for steelmaking slag were developed in a variety of industries. Now days, due to a relatively high share of electric-furnace steel in the total amount of steel produced throughout the world, thus also the growth of available amounts of this type of waste, steel slag is becoming increasingly important, while the application of steel slag is also rapidly growing in the developed countries. Through awareness of environmental considerations and more recently the concept of sustainable Sustainable Development