Dynamic compressive properties of lightweight rubberized concrete

This study experimentally examines the dynamic characteristics of concrete made of waste car tyres as both fine and coarse aggregates (rubberized concrete), resulting in light-weight concrete with the densities of 2350 kg/m³, 2091 kg/m³, and 1833 kg/m³ for 0%, 15%, and 30% rubber content, respectively. The dynamic compressive characteristic of the rubberized concrete was quantified by using a Split Hopkinson Pressure Bar equipment up to the strain rate of 182 s⁻¹. The experimental results have consistently shown excellent impact resistance of rubberized concrete as compared to that of normal concrete, including the progressive failure, crack propagation and normalized energy absorption. Under the same impact, rubberized concrete was still almost intact while normal concrete was fragmented into pieces. Rubberized concrete significantly slowed down the crack propagation and exhibited progressive failure as compared to normal concrete. The compressive strength and axial strain at maximum dynamic stress of rubberized concrete are sensitive to the strain rate and the sensitivity increases with the rubber content. Young's modulus of rubberized concrete showed inconsistent strain rate sensitivity. Meanwhile, rubberized concrete was more sensitive to the strain rate than normal concrete. In addition, new equations to estimate the DIFs of rubberized concrete with different rubber contents were proposed, in which the lateral inertia confinement effect was removed.