Influences of Organic Fiber on After-high-temperature Performance of Tunnel Segment High Performance Concrete

In this paper,the high temperature automatic acquisition system was designed based on the temperature sensor,and the inside temperature of concrete was monitored under fire and high temperature environment,and effects of organic fiber on tunnel segment concrete properties after high temperature were studied.The experimental results showed that from the inside to the outside of concrete existing an obvious temperature gradient during the fire,synthetic organic fiber could obviously reduce the cracking and spalling of concrete induced by the temperature gradient;decomposition temperature of polypropylene fiber was higher than that of cellulose fiber and polyvinyl alcohol fiber,the flexural strength,fracture energy,fracture toughness,and residual strength of polypropylene fiber reinforced concrete were superior to polyvinyl alcohol fiber reinforced concrete and cellulose fiber reinforced concrete,so the polypropylene fiber was more suitable for improving the anti-crack performance of tunnel segment concrete in the high temperature environment.