Sustainable 3D printed engineered cementitious composites incorporating recycled ceramic materials: Rheology and mechanical behavior

Developing sustainable engineered cementitious composites (ECC) for additive manufacturing is essential to reducing resource consumption and environmental impact in the construction sector. This study presents a green ECC system where fly ash and quartz sand are partially replaced with ceramic polishing powder (CPP) and recycled ceramic sand (RCS), while polyethylene (PE) fibers are partially substituted with basalt fibers (BF). The effects of these replacements on rheology, printability, mechanical behavior, interlayer bonding, cost, and carbon footprint were comprehensively evaluated. Results show that moderate incorporation of CPP and RCS enhances slurry stability and printing quality by improving particle packing and inducing secondary pozzolanic reactions. Mechanical performance, including compressive and tensile strength as well as ultimate strain, reaches optimal levels at intermediate replacement ratios (50 %). The compressive strength of printed ECC reached 54.02 MPa, and the tensile strength and ultimate strain increased by 29.9 % and 33.2 %, respectively. CPP also strengthens interlayer bonding and mitigates mechanical anisotropy in printed specimens. Conversely, replacing PE fibers with BF reduces carbon emissions and cost but compromises tensile performance and interfacial toughness due to limited fiber bridging. Therefore, when partially replacing fibers with basalt fibers (BF), the replacement ratio should not exceed 25 % to enhance environmental performance while avoiding significant reductions in tensile strength and interfacial toughness. • CPP and RCS improve rheology and printability of ECC for 3D printing. • Optimal CPP/RCS content (25–50 %) enhances strength and ductility. • CPP and RCS enhance interlayer bonding and reduce anisotropy. • Basalt fiber lowers cost but reduces tensile and interfacial strength.