Synergistic optimization: A comprehensive life cycle assessment for high-performance concrete with recycled aggregates and Next-Gen nylon waste fibers

The increasing use of natural resources and pollution caused by construction industries has spurred interest in eco-friendly materials such as recycled aggregates and recycled fibers. This research focuses on evaluating the effects of incorporating varying proportions of RCA and NWFs into HPC on its engineering characteristics and emissions. The environmental effects of the formulated blends on the HPC mixes were evaluated. The system boundary was determined based on cradle-to-gate theory, and Ecoinvent 3.10 was used as the background database for assessing the impacts of concrete mixes. Life cycle Impact assessment was carried out with the help of SimaPro software using CML baseline method. The findings reveal that introducing 0.25–0.5 % NWFs optimizes STS for all RCA percentages. NWFs also effectively mitigate the negative influence of RCA on CS. Incorporating 0.25 % NWFs enhances durability aspects related to permeability. Emissions related to CS are minimized in concrete mixes with 0.25 % NWF, particularly at 75 % RCA substitution levels. Portland cement dominates emissions in concrete, constituting 84.03 % without RCA and escalating to 91.35 % at complete substitution. It significantly influences the GWP, ETP and ADP. NCA exerts the highest environmental impact on FAETP 18.53 % without RCA and notably affects ODP and HTP, while RCA proves more sustainable, with a 66 % reduction in GWP compared to NCA, due to its recycled origin and lower energy demands in production. The optimal transport distance for 75RCA ranges from 25 km to 145 km with specific limits for different impact categories.