Application of electric arc furnace slag as an alternative precursor to blast furnace slag in alkaline cements

Abstract

In steel manufacturing, electric arc furnaces are increasingly common, as they use mostly scrap metal as ore source. Thus, blast furnace slag (BFS) is decreasing, while electric arc slag (EAFS) is proportionally increasing. This study focuses on the potential of EAFS in alkaline cements, as precursor or aggregate. Different EAFS/BFS mixtures, some including fly ash (FA), were activated with a NaOH solution, and characterized from a mechanical and microstructural perspective. Selected pastes were used to prepare mortars, using EAFS as aggregate. Results showed that EAFS alone doesn’t deliver an adequate strength. However, when combined with BFS and FA, it formed compact matrices with significant mechanical strength and lower hydration heat. The use of EAFS as aggregate produced higher strength than obtained with silica sand. EAFS showed the potential to be applied as a precursor in alkaline cements, and the combination of BFS/EAFS yielded higher compressive strengths than obtained with BFS alone.