Rubberized concrete: A green structural material with enhanced energy-dissipation capability

This study presents rubberized concrete composite as a new structural material aiming for an enhanced energy dissipation capability and thus improved seismic performance by mixing recycled rubber crumb with concrete. While rubberized concrete is not new, this study represents the first investigation on damping and dynamic (including seismic) behaviors of rubberized concrete for its potential application as structural material. Small-scale column models were fabricated using rubberized concrete with different proportions of rubber crumb to evaluate the structural dynamic performance, including free vibration tests to identify damping ratios and seismic shaking table tests to investigate the structural responses to earthquake ground motion. Meanwhile, rubberized concrete cylinders were tested to evaluate compressive strength and modulus of elasticity. It was observed that the damping coefficient of the rubberized concrete increased by 62% compared with normal concrete and, as a result, the seismic response acceleration of the structure decreased by 27%. However the concrete suffered from reduction in compressive strength as rubber crumb was added. It was found that adding silica fume to rubberized concrete improved the bonding between the rubber and cement and thus the concrete strength. Overall, this study demonstrated the potential of using the environmentally-friendly rubberized concrete as structural material to enhance dynamic performance and reduce seismic response of concrete structures.