The research paper presented a comprehensive and detailed investigation into the flexural behavior of concrete beams incorporating PVC pipes filled with waste-crumbed rubber. The study aimed to explore the potential of utilizing waste-crumbed rubber as a partial replacement for conventional coarse aggregates in concrete beams, with the addition of PVC pipes as a reinforcement element. To conduct the study, laboratory specimens were prepared using a mix ratio of 1:1.5:3 (M20), and varying proportions of rubber crumbs were incorporated into the concrete mix. The rubber crumbs were carefully placed within PVC encasings, and the concrete beams were subsequently cast. The research team carefully controlled the replacement percentages, which included 1, 3, 5 and 7% of the total volume of coarse aggregate. The primary objective of the investigation was to assess the impact of incorporating waste-crumbed rubber on the flexural strength of the concrete beams. To achieve this, the researchers conducted extensive testing and analysis, focusing on parameters such as compressive strength, flexural strength, and load–deflection behavior of the beams. The results of the study revealed a significant improvement in the flexural behaviour of the concrete beams with the addition of crumbed rubber. As the percentage of rubber content increased up to 5%, the flexural strength of the beams also showed a progressive increase. However, beyond the 5% threshold, no significant change in flexural strength was observed with further additions of rubber. Specifically, the flexural strengths for conventional beams and PVC-filled beams with rubber were found to be 13.5, 15.3, 16.6, 17.1, and 17.0%, respectively. The findings indicate that incorporating PVC pipes filled with waste-crumbed rubber can effectively enhance the flexural strength of concrete beams. The elastic and resilient nature of rubber particles contributes to the energy absorption capacity of the beams, resulting in improved load-carrying capabilities and resistance to deformation. Additionally, the interlocking of rubber particles with the surrounding matrix material enhances the overall structural integrity of the composite beams. It is evident that there exists an optimal percentage of rubber replacement that provides the maximum benefit in terms of flexural strength enhancement. Beyond this point, further additions of rubber might not yield significant improvements and could potentially lead to practical challenges in workability or density. The study’s outcomes underscore the importance of optimizing the rubber content to achieve the desired improvements in concrete beam performance. By selecting the appropriate percentage of rubber replacement, engineers can strike a balance between enhanced flexural strength and other critical mechanical properties. The scope of the study covered a limited range of rubber content percentages, and a more extensive dataset encompassing a wider range of rubber contents would provide a more nuanced understanding of the relationship between rubber filling and beam strength. Moreover, the researchers highlighted the need to explore the long-term durability, environmental impact, and cost-effectiveness of rubber-filled beams. The study presented in the research paper adds valuable insights into the potential of incorporating waste-crumbed rubber in concrete beams, along with PVC pipes as a reinforcement method. The results demonstrate the feasibility of this approach to enhance the flexural strength of concrete beams, making them more resilient and durable under cyclic loading. In conclusion, the research showcases the promising possibilities of utilizing waste-crumbed rubber in sustainable construction practices. It emphasizes the importance of carefully optimizing the rubber content to achieve the desired improvements in flexural strength and highlights the need for further research to explore the broader implications of this approach. With continued investigation and refinement, incorporating PVC pipes filled with waste-crumbed rubber could pave the way for more efficient, environmentally friendly, and resilient construction practices. © 2024 Elsevier B.V., All rights reserved.