Engineered cementitious composites (ECCs) have been established as a feasible option for repairing structures that no longer meet safety and serviceability standards. However, the large quantities of cement used in the composite resulting in a high carbon footprint and the high material cost associated with polyvinyl alcohol (PVA) fibers make improvements essential for a broader application. In this study, modified mix designs of ECCs were investigated using supplementary cementitious materials (limestone and metakaolin) to replace up to 70% of OPC and 100% of fly ash in combination with substituting PVA fibers with polypropylene (PP) fibers. As part of a broader study, the mechanical behavior of these mixes was examined by four-point bending tests and uniaxial tension tests and compared to the standard M45-ECC. It could be observed that as cement content is reduced, there is no significant additional loss of mechanical properties by simultaneously replacing PVA fibers with more cost-efficient PP fibers. The developed mix designs retain a high tensile strain capacity and tensile strength while enhancing sustainability and lowering the cost of the material. The results of this study present a promising approach to promote a broader application of ECCs in infrastructure repair.