Thermo-Mechanical Performance of Rubberized Concrete: A Sustainable Alternative to Conventional Aggregates

In response to increasing environmental challenges and the global demand for sustainable construction materials, this study explores the potential of rubberized concrete incorporating crumb rubber as a partial replacement for fine aggregate. The primary objective is to evaluate the influence of rubber content (0% to 50%) on the thermo-mechanical properties of concrete, including compressive strength, split tensile strength, flexural strength (modulus of rupture), elastic modulus, and thermal properties such as conductivity, expansion, heat resistance, and heat capacity. A total of 128 concrete specimens were prepared using a fixed mix ratio (1:1.05:2.46) with a water-to-cement ratio of 0.47. Experimental tests were conducted to determine slump, density, mechanical strengths, and thermal characteristics. Results revealed that increasing crumb rubber content significantly reduced compressive strength (from 42.61 MPa to 15.69 MPa), split tensile strength (from 1.81 MPa to 1.09 MPa), and flexural strength (from 4.53 MPa to 2.70 MPa), while enhancing workability and thermal insulation. Thermal conductivity decreased from 0.947 W/m·K to 0.614 W/m·K, indicating better insulation capacity. Although elastic modulus and thermal expansion were not directly tested, reduced density and improved thermal behavior suggest favorable performance under high-temperature conditions. The novelty of this work lies in its systematic investigation of high-volume crumb rubber replacement and the integration of both mechanical and thermal analyses, addressing a gap in existing research. These findings demonstrate the suitability of rubberized concrete for non-structural or thermally demanding applications such as fire-resistant walls and insulating elements, while also promoting solid waste recycling and sustainable building practices.