Sustainable engineered cementitious composites incorporating recycled materials: Experimental validation and life cycle assessment

The use of recycled constituents in engineering cementitious composites (ECC) offers a promising pathway to reduce the environmental burden of cement-based materials while maintaining high mechanical performance. In this study, recycled concrete powder (RCP) and waste tire steel fiber (WTSF) were incorporated into ECC, and their mechanical and environmental performance was evaluated through experimental testing, Digital Image Correlation (DIC), Scanning Electron Microscopy (SEM) and life cycle assessment (LCA). DIC was used during flexural testing to quantify surface deformation and characterize crack initiation and propagation, while SEM was employed to evaluate fiber-matrix interaction, microstructural features, and crack-bridging mechanisms. A cradle-to-gate LCA was compare the environmental impacts of cement, RCP, industrial steel fibers, WTSF, and sustainable ECC mixtures. The experimental results show that the sustainable ECC mixtures maintained competitive flexural performance, with the highest flexural strengths reaching 44.5 MPa for a mixture containing 2% WTSF and 43.5 MPa with 2% polyethylene fiber. The LCA results for the complete sustainable ECC mixtures demonstrated reductions in climate change potential and fossil resource consumption compared with conventional ECC mixtures. These findings demonstrate the potential of recycled-material-based ECC to support sustainable, low-carbon, and circular construction practices without compromising structural performance. Overall, the findings support RCP and WTSF as effective low-carbon alternatives for ECC, enabling improved sustainability without compromising structural performance.