Influence Of Corrosion Deterioration On Reinforced Concrete's Fire Resistance

As time goes by,buildings will be eroded by the environment,which causes damage to the structure.Moreover,fire can also cause great damage to reinforced concrete.High strength reinforced concrete is more likely to burst under high temperature.Currently,adding polypropylene fiber into reinforced concrete is one of the most commonly used means to improve the fire resistance of reinforced concrete.In order to simulate the real fire scenario,studying the effect of high temperature on the fire resistance of high strength reinforced concrete in corrosion condition.At the same time,adding polypropylene fiber to high strength reinforced concrete,and studying the effect of polypropylene fiber on high strength reinforced concrete under high temperature.In this paper,high strength reinforced concrete,polypropylene high strength reinforced concrete,corroded high-strength reinforced concrete and corroded polypropylene high strength reinforced concrete are as research objects.Based on the experimental research,adopting the method of macro analysis,data analysis and theoretical analysis,and the effect of corrosion and high temperature on high strength reinforced concrete and polypropylene high strength reinforced concrete is studied.Then analyzing the damage characteristics of reinforced concrete under corrosion deterioration condition and high temperature deterioration conditions.The specific contents are as follows:(1)Damage characteristics of reinforced concrete under corrosion deterioration conditionAdopting full submerged power supply to accelerately rust high strength reinforcedconcrete and polypropylene high strength reinforced concrete.The law of accelerated corrosion process of reinforced concrete is summarized through the current density time-varying process and theoretical analysis.By studying the macroscopic appearance characteristics and the longitudinal wave velocity's variation of corroded reinforced concrete,the damage caused by corrosion deterioration to reinforced concrete is analyzed.(2)Damage characteristics of reinforced concrete under high temperature deterioration conditionsA box type resistance furnace is used to heat different types of reinforced concrete(such as high strength reinforced concrete,polypropylene high strength reinforced concrete,corroded high strength reinforced concrete and corroded polypropylene high strength reinforced concrete).The fire resistance of different types of concrete at different temperatures is studied.The fire resistance is including concrete's variation of apparent characteristics,mass loss of concrete and concrete's variation of longitudinal wave velocity after high temperature action.The results show that the addition of polypropylene fiber has no effect on the high strength reinforced concrete of laws and phenomenon in the rust,and the damage degree of high strength reinforced concrete on the axial by the corrosion is greater than that the transverse.Corrosion will increase the damage degree of high temperature to reinforced concrete structure,especially in the evaporation stage of capillary water and gelled water in concrete.The maximum damage degree to the reinforced concrete structure is 212.2%,and the average value is 15.8%.Adding polypropylene fiber can effectively increase the fire resistance of reinforced concrete.Adding polypropylene fiber to corroded high strengthreinforced concrete can also effectively inhibit the damage effect to reinforced concrete on high temperature.