Influence of steel fiber content on the rate-dependent flexural performance of ultra-high performance concrete with coarse aggregates

Steel fiber is widely used to improve the flexural performance of ultra-high concrete (UHPC), yet synergistic effect steel and coarse aggregates in UHPC containing (UHPC-CA) has not been elucidated. Here, influence content on rate-dependent UHPC-CA investigated from view aggregates. Results reveal that increasing pull-out force due increase crack mouth opening speed at a higher loading rate responsible for curve type transition UHPC-CA. The first stress insensitive content. However, dynamic factors (DIFs) strength energy absorption capability decrease with content, which attributed lower propagation A model concerning critical angle fracture proposed.