Fire Resistance Of Concrete Structures With Composite Rod Reinforcement

Abstract

The use of composite rod reinforcement makes it possible to ensure the durability of reinforced concrete structures, operated under aggressive conditions. The use of composite reinforcement in concrete structures requires solving the problem of fire resistance of this class of structures. The fire resistance of the composite rod reinforcement is determined by the moment of softening of the composite rod matrix as a result of heating under fire conditions. The maximum temperature for various composite materials is 150 °Ñ – 250 °C. When designing, it is necessary to ensure the normative value of the limit of fire resistance of structures. For the bearing structures of the frame, the fire resistance limit corresponds to the moment of loss of the bearing capacity, for the intermediate floors – the loss of bearing capacity, integrity and thermal insulation ability. The main factor that provides the fire resistance of concrete structures with rod composite reinforcement is the thickness of the protective layer of concrete which ensures the joint operation of composite rods with concrete. Diagrams of the temperature change over the thickness of a concrete structure are presented, on the basis of them the methodology for the assignment of the value of the protective layer of concrete for the core composite reinforcement for different designs with due regard for the duration of fire effect in case of fire is proposed. The nomenclature of structures in which it is possible to use the rod composite reinforcement with the provision of regulatory requirements for the limit of fire resistance is determined.