Abstract: The fire resistance of T shape concrete members was studied by using a self-designed combustion furnace.By observing the apparent phenomenon of the component after fire and measuring the internal temperature changes of the composite member during the fire of 120 min, the distribution rule of internal temperature and high temperature damage of concrete under fire,which is composite member composed of concrete walls and slabs, were obtained. The results showed that the concrete spalling phenomenon is more likely to occur at the exposed fire side of the concrete wall under fire, and the fire protection measures such as fire-retardant coating should be taken at this position to reduce the impact of high temperature of the fire. The concrete temperature in the joint core area of the composite member is generally lower than that in other heated areas, and the wall and slab have a certain protective effect on the joint core area. The farther away from the fire-heated surface, the lower the internal temperature of the concrete composite member under fire, and the longer the reaction time till the temperature begins to rise. The temperature of the composite member is lower in the non-heated area, the reaction time of the temperature rise is longer and the speed is slower, and the high temperature has less influence on the structure of the non-heated area.

Key words: concrete composite member, fire resistance, high temperature damage, model experiment, temperature field distribution