On-ground slabs using carpet fibre-reinforced Concrete: Comparative life cycle environmental and cost assessment with recycling pathways

<p dir="ltr">Carpet fibre reinforced concrete (CFRC) presents an environmentally sustainable alternative to conventional concrete by integrating post-consumer carpet waste, diverting material from landfills while enhancing mechanical performance—particularly by reducing shrinkage cracking and improving durability. Despite this promise, limited research has explored the life cycle environmental and economic performance of CFRC. This study conducts a comprehensive cradle-to-grave Life Cycle Assessment (LCA) with open-loop recycling and Life Cycle Cost Analysis (LCCA) for CFRC in on-ground slab applications under Australian conditions, benchmarked against control concrete and steel fibre reinforced concrete (SFRC). Using a consistent functional unit and system boundary, the results reveal that CFRC has the lowest environmental impact across all midpoint impact categories, including an 8.6 % reduction in Global Warming Potential (GWP) compared to SFRC. Parallel cost analysis shows CFRC also offers the lowest life cycle cost—26.5 % lower than control concrete and 13.2 % lower than SFRC. Although the initial production cost is slightly higher than normal concrete, long-term savings are primarily driven by reduced maintenance needs. The financial feasibility analysis further confirms CFRC's economic potential, with a Net Present Value (NPV) of A$4.01 million and an Internal Rate of Return (IRR) of 87.8 %. While CFRC shows only modest environmental differences from the control mix, it delivers downstream cost savings and diverts carpet waste from landfill. This study presents the first combined LCA and LCCA of CFRC under Australian conditions, demonstrating that even small environmental gains, when coupled with substantial economic benefits, can support the adoption of waste-based concrete. Overall, the results highlight CFRC as a financially attractive option for manufacturers. Advantages stemming largely from reduced maintenance requirements over the service life.</p>