Experimental investigation of the dynamic properties of polypropylene fiber-reinforced rubberized recycled concrete

This study investigates the dynamic properties of fiber-reinforced rubberized recycled concrete incorporating recycled coarse aggregate (RCA), crumb rubber (CR), and polypropylene (PP) fiber through free vibration testing. Nine reinforced concrete columns (150×150×950 mm) incorporating 30% RCA, 0-15% CR, and 0-0.5% PP fiber were prepared and tested under three impact energies. The measured acceleration responses were used to evaluate natural frequency, time period, damping ratio, and damping coefficient. Results showed that CR increased the displacement and natural time period. Although the damping ratio increased with CR content, the damping coefficient decreased beyond a certain CR percentage due to reduced natural frequency. On the contrary, incorporating fiber reduced displacement, enhanced the damping ratio and damping coefficient, and maintained time periods comparable to conventional concrete. Moreover, the curvature ductility improved further by incorporating fiber in addition to CR. This study concludes that PP fiber can improve the dynamic performance of rubberized recycled concrete for sustainable structural applications.