Life cycle impact of concrete incorporating nylon waste and demolition waste

The large consumption of natural resources by the construction industry and resultant pollution have inspired the necessity to investigate the potential of eco-friendly materials, such as recycled aggregates and recycled fibers. In this study, the effect of different percentages of recycled coarse aggregate (RCA) and nylon waste fibers (NWFs) was investigated on engineering performance and performance-related carbon emissions of high-performance concrete (HPC). Engineering performance indices include compressive strength (CS), splitting tensile strength (STS), water absorption (WA), and chloride ion penetration (CIP). The environmental impact of designed mixes was evaluated using a cradle-to-gate life cycle assessment approach on the HPC mixes. The results showed that the incorporation of 0.25-0.5% yielded maximum STS for all percentages of RCA. The use of NWF helped overcome the negative impact of RCA on the STS of HPC. The use of the 0.1-0.25% volume of NWF was beneficial to the permeability-related durability indicators of HPC. CS-related emissions were minimum for concrete mixes incorporating 0.1-0.25% NWF with 0% and 50% substitution levels of RCA. While STS-related emissions were lowest for HPC incorporating 0.5% NWF with 50% and 100% substitution levels of RCA.