Experimental evaluation of Shear strength of BOF and EAF steel slag aggregates in dry, submerged and dry-submerged conditions

One of the most important by-products of steelmaking and refining processes is steel slag. It is necessary to determine the geotechnical engineering properties of steel slag and assess their potential use in road and railways embankment constrictions. In this paper, the shear strength properties of steel slag were studied. Two types of steel slag, Blast Oxygen Furnace (BOF) and Electric Arc Furnace (EAF) slags that generated in Esfahan Steel Company and Mobarakeh Steel Company are used in this paper. The grain size distributions range of the test specimens have been selected under the characteristics of the road pavement and the existing laboratory facilities. In this study, two slags (BOF, EAF) with two grain size distribution and two difference compaction energy (standard and modified compaction) and the effect of saturation in California bearing ratio were evaluated. The results of the atterberg limits test showed that the material is none plasticity. The results of the compactions tests showed that dry unit weight varied between 1.94 to 2.74 gr/cm3 and optimum moisture content varied between 8% and 12.5%. Based on the California Bearing Capacity (CBR) tests, the CBR varied between 88 to 199 for BOF slags and 185 to 490 for EAF slags in socked and unsoaked conditions. In this study, direct shear experiments were performed on two types of granulation under four vertical stresses of 25, 50, 100 and 150 kPa in dry, submerged and dry-submerged. Based on the results, the above slags have an internal friction angle between 28 and 68 degrees and the adhesion of these materials was between 0 to 32 kPa. These results showed that steel slag has a much higher shear strength than natural soil and, according to the results of experiments, can be used as a material in engineering embankments.