Development of sustainable HPC using rubber powder and waste wire: carbon footprint analysis, mechanical and microstructural properties

This research advances the development of eco-friendly high-performance concrete (HPC) by integrating tire rubber powder and waste wire, focusing on both enhanced mechanical properties and reduced environmental impact. Substituting up to 40% of silica sand with rubber powder helps maintain the compressive strength necessary for high-strength concrete applications. The addition of waste wire is designed to improve ductility. A comprehensive evaluation includes mechanical and microstructural analyses, such as compressive, splitting tensile, and flexural strength assessments, in addition to Scanning Electron Microscopy (SEM) and Differential Thermal Analysis (DTA). Environmental implications are assessed by measuring the embodied carbon footprint. Findings indicate that the absence of rubber powder allows for a compressive strength peak of 95 MPa, while 50% rubber content leads to a decrease to 25 MPa, establishing a 40% rubber threshold for optimal strength. Conversely, 3% waste wire reinforcement enhances the strength to 106 MPa. Microstructural investigations reveal that increased rubber content adversely affects compressive strength by weakening the cement matrix, and reducing calcium-silicate-hydrate (C-S-H) formation. Significantly, the study reveals that replacing silica sand with rubber powder, along with waste wire reinforcement, substantially reduces the carbon footprint of the material, contributing to more sustainable construction methodologies.