Engineering performance evaluation of mortar with EOS (electric arc furnace oxidizing slag) as fine aggregate

Electric arc furnace oxidizing slag (EOS), in the fine aggregate form, can effectively be utilized as a construction material. However, its engineering properties vary with the manufacturing processes employed and the producing district, thereby causing observed differences in material performance. In this study, EOS was obtained from steel manufacturing plants in South Korea, and engineering properties of standalone EOS, as well as in combination with cement mortar were separately evaluated. Test results demonstrate that EOS primarily comprises CaO, SiO₂, and FeO in combination with 18.2% larnite, which possesses β-C₂S crystal structure with a similar cement mineral. The EOS mortar combination demonstrated increasing compressive strength with an increase in EOS content due to the effect of a considerable amount of β-C₂S present in EOS. The EOS-based mortar with electric arc furnace reduction slag (ERS) demonstrated unsatisfactory results in accordance with a criterion set for the length rate of change. This implies that more consideration is required toward the use of mixed ERS and EOS in cement mortars due to the swelling effect of ERS on dimensional stability.