This study explores the compressive performance of steel–concrete composite sections encased with self-compacting concrete (SCC) that incorporates rubber powder derived from recycled tyres. Given the growing emphasis on sustainable construction materials, the research highlights the advantages of integrating industrial by-products, such as rubber powder, into concrete mixtures. The primary goal is to assess the impact of replacing conventional aggregates with rubber powder on compressive strength, stress–strain behavior, and failure mechanisms in composite sections. To achieve this, a series of experimental tests will be conducted using different SCC mixtures with varying rubber powder proportions. The mechanical properties of these composite sections will be evaluated through standardized compressive testing, enabling a thorough analysis of their load-bearing performance. The expected outcomes of this research aim to provide valuable insights into optimizing SCC formulations to enhance both structural efficiency and sustainability. By investigating the influence of rubber powder on compressive behavior, this study seeks to determine its potential for improving ductility and energy absorption in composite sections. The findings are anticipated to contribute to the development of eco-friendly building materials, aligning with circular economy principles by minimizing construction waste. Ultimately, this research not only addresses the demand for sustainable construction solutions but also promotes the reuse of industrial by-products, fostering innovation within the construction sector.