Abstract: The thermal performance of polypropylene fiber reinforced concrete (PFRC) with different fiber content and fiber length after high temperature treatment is experimentally studied by transient heat source method. The results show that: The apparent density, thermal conductivity, thermal diffusivity and specific heat of PFRC decrease with the increase of heated temperature; The porosity increases with the increase of temperature, the content and length of polypropylene fiber have no significant influence on the apparent density and porosity of concrete, demonstrating that the concrete mass loss and the porosity raise are mainly attributed by the loss of water and the dehydration reaction of hydrates; The concrete with high fiber content has small thermal conductivity and thermal diffusivity after exposure to high temperature.

Key words:  high temperature, polypropylene fiber reinforced concrete, fiber length, fiber content, thermal parameters