Investigation on the quasi-static mechanical properties and dynamic compressive behaviors of ultra-high performance concrete with crumbed rubber powders

Incorporating crumbed recycled rubber powders as aggregate has great potential for improving the impact resistance of concrete and easing the environmental issue caused by the disposal of waste tires. This study was conducted to evaluate the effect of rubber powders on the properties of ultra-high performance concrete (UHPC). River sand was replaced by the same volume of rubber powders at different ratios of 5, 10, and 15% in UHPC. The flowability, quasi-static mechanical properties, and dynamic compressive properties of UHPC containing crumbed rubber powders were thoroughly investigated. The experimental results showed that rubber powders reduced the flow of UHPC. The poor bonding between rubber powder and cement paste compromised the quasi-static mechanical properties of UHPC. However, with the increasing content of rubber powders, the extent of damage and the brittle behavior of UHPC under impact loading were restrained significantly. Rubber powders enhanced the dynamic compressive properties of UHPC by increasing the tortuosity of cracks and dissipating energy. The dynamic strength quantified by the dynamic increase factor was more sensitive in UHPC with rubber powders than that in control mix. In addition, new linear fitting curves to predict the dynamic increase factor of UHPC with different contents of rubber powders were proposed.