Author(s): Lukas Reinhardt and Clara Vogel

Abstract: The growing demand for sustainable construction materials and the rapid generation of construction and demolition waste have intensified the need to explore recycled aggregate concrete (RAC) as a viable alternative to conventional concrete in urban infrastructure. This study evaluates the mechanical, durability, and life-cycle performance of RAC incorporating treated and untreated recycled concrete aggregate (RCA) at varying replacement levels (0%, 25%, 50%, 75%, and 100%) of natural coarse aggregate. A comprehensive experimental program was conducted to determine workability, compressive and tensile strengths, modulus of elasticity, water absorption, chloride permeability, sorptivity, and freeze-thaw resistance. Statistical analysis using one-way ANOVA confirmed that RCA replacement significantly affects strength and durability indices, although surface pretreatment effectively mitigated performance degradation. Results indicated that up to 50% RCA replacement with pretreatment maintained compressive strength within 10-15% of control concrete, while reducing chloride permeability and water absorption compared to untreated mixes. Life-cycle assessment further revealed that embodied CO? emissions and energy consumption decreased by approximately 8-15% with higher RCA content, validating the environmental benefits of recycled aggregate usage. The study concludes that RAC, when designed with appropriate material control and pretreatment, can meet the mechanical and durability requirements for various urban infrastructure applications, while contributing to waste reduction and carbon footprint minimization. Practical recommendations emphasize adopting performance-based specifications, integrating supplementary cementitious materials, and implementing recycling quality standards to promote RCA utilization in urban construction projects. This research establishes a scientific basis for expanding RAC adoption in sustainable infrastructure development and provides actionable insights for engineers, policymakers, and sustainability practitioners aiming to achieve circular economy goals in the construction sector.

Pages: 36-42 | Views: 7 | Downloads: 6

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