Despite extensive research on fiber-reinforced lightweight concrete, the synergistic effects of combining different types of fibers, such as polymer and basalt fibers, on the mechanical properties and durability of lightweight concrete have not been fully investigated. This study aims to fill this scientific gap by examining the combined use of polymer and basalt fibers to enhance the performance of lightweight concrete (LWC). Lightweight concrete is widely used to reduce the weight of structures and improve seismic performance. However, its brittle nature and lower mechanical properties compared to normal-weight concrete (NWC) limit its application in high-stress environments. This study seeks to overcome these limitations by optimizing the use of polymer and basalt fibers to improve the mechanical properties and durability of lightweight concrete. In this research, 320 cylindrical samples were prepared, and the results show that adding 1% polymer fibers significantly improved the compressive and tensile strengths of lightweight concrete by 24.4% and 66.13%, respectively, at 28 days. Additionally, the combination of polymer and basalt fibers showed a positive synergistic effect, leading to improved mechanical properties and durability of the concrete, including a 45.38% reduction in final water absorption and a 43.15% reduction in chloride ion penetration at 90 days. This study provides new insights into the synergistic effects of polymer and basalt fibers in lightweight concrete and proposes a practical solution for improving its mechanical properties and durability. The findings of this research contribute to the development of lightweight concrete structures with greater reliability and flexibility.
