Rubber-Modified Self-Compacting Concrete: Mechanical Performance and Cradle-to-Gate Life Cycle Assessment for Low-Load Applications

This study investigates the utilization of recycled tire rubber in self-compacting concrete (SCC) as a sustainable construction technology aligned with circular economy principles and climate change mitigation. Rubber powder (≤150 µm) replaced limestone powder, and rubber granules substituted fine aggregates at 10%, 20%, and 30% by volume. Mechanical testing revealed a 15–25% reduction in compressive and tensile strengths, primarily due to increased porosity and weak interfacial transition zones. However, replacing limestone powder with fine rubber enhanced microstructural densification through a filler effect: the mixture with 30% rubber powder (CRLW3) achieved a 28-day compressive strength of 38 MPa. Life cycle assessment (LCA), conducted using SimaPro and the Ecoinvent 3.8 database, demonstrated a 45% reduction in CO₂ emissions and global warming potential, along with 56% and 40% decreases in acidification and eutrophication potentials, respectively. These results indicate that rubberized SCC, particularly with fine rubber powder, offers a viable and environmentally beneficial alternative for non-structural applications such as pavement base layers, lightweight concrete blocks, and noise-absorbing barriers, where ecological advantages outweigh the need for high mechanical performance.