Author(s): Ethan J McAllister

Abstract: This study investigates the seismic behavior of reinforced concrete (RC) frames incorporating recycled aggregate concrete (RAC) with varying levels of recycled concrete aggregate (RCA) replacement. The research aims to evaluate how the substitution of natural coarse aggregate (NCA) with RCA influences the strength, ductility, stiffness degradation, and energy dissipation of RC frames under cyclic lateral loading. Three frame types were constructed^-control (100% NCA), RAC-50 (50% RCA), and RAC-100 (100% RCA)^-and tested using a quasi-static reversed cyclic loading protocol simulating seismic actions. Experimental results demonstrated that increasing RCA content led to a progressive reduction in compressive strength, lateral load capacity, ductility factor, and cumulative energy dissipation. The RAC-50 frames, however, retained adequate seismic performance, with ultimate drift capacity and energy dissipation comparable to the control frames, while RAC-100 exhibited pronounced stiffness degradation and larger residual drifts. Statistical analysis through permutation ANOVA confirmed significant differences among groups, reinforcing that the degradation of structural parameters correlates directly with RCA proportion. Despite moderate reductions in mechanical and seismic properties, the RAC-50 frames satisfied essential ductility and deformation criteria, indicating their suitability for structural applications in medium seismic zones. The study concludes that partial RCA replacement offers a sustainable and technically viable alternative to natural aggregates when combined with proper mix proportioning, reinforcement detailing, and quality control. The research also proposes practical recommendations for optimizing mix design, improving RCA quality, and refining design guidelines to promote the safe and sustainable use of RAC in earthquake-resistant construction.

Pages: 51-56 | Views: 4 | Downloads: 3

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