Feasibility study of developing green ECC using iron ore tailings powder as cement replacement

This paper reports the results of an initial attempt of using iron ore tailings (IOTs) to develop greener engineered cementitious composites (ECCs). ECC is a unique class of high-performance fiber-reinforced cementitious composites featuring high tensile ductility and durability. However, the high cement usage in ECC limits the material greenness and increases the material cost compared with normal concrete. In this paper, IOTs in powder form are used to partially replace cement to enhance the environmental sustainability of ECC. Mechanical properties and material greenness of ECC containing various proportions of IOTs are investigated. The newly developed versions of ECC in this paper, with a cement content of 117.2-350.2 kg/m³, exhibit a tensile ductility of 2.3-3.3%, tensile strength of 5.1-6.0 MPa, and compressive strength of 46-57 MPa at 28 days. The replacement of cement with IOTs results in 10-32% reduction in energy consumption and 29-63% reduction in carbon dioxide emissions in green ECC compared with typical ECC. Thus, the feasibility of producing greener ECC with significantly reduced environmental impact using IOTs, and maintaining the mechanical properties of typical ECC, is experimentally demonstrated in this paper.