Study on Exposure of Reinforcing Bars and Concrete to Fire - A Review

In this modern era, most of the buildings all over the world are made up of RCC. The increasing incidents of fire in buildings have increased the importance of assessment; repairs and rehabilitation of such buildings as these buildings are very costly. This field needs special expertise in many areas viz. concrete technology, structural engineering, material testing, and repairs and maintenance etc. A continuous effort through research and development programmes all over the world is being made in this specialized field. This topic gives us immense pleasure as we deal with the real life problems in this research. In this research, we gain the knowledge which is being used as a strategy for the rehabilitation of fire damaged buildings and by conducting proper assessment procedures by non-destructive techniques. In this research, we did various experiments so as to find out the effect of fire on the reinforcing bars in RCC buildings by taking 6 samples at 110°, 310°,610°,900° each for 3 hours. After heating the samples, they are cooled quickly by quenching in water and normally by air cooling. It is seen that there is a change in the mechanical properties of samples which are studied under universal testing machine (UTM) and for close look at reinforcing bars in a fire damaged structure, scanning electron microscope (SEM) is used. From conclusions, it is seen that most of the fire damaged RCC are restorable. The mechanical properties of all common building materials decrease with the elevation of temperature. The behavior of a RCC in fire conditions is governed by properties of constituent materials, concrete and steel at high temperature. Both concrete and steel undergo considerable change in their strength, physical properties, and stiffness by the effects of heating. It is also seen that above 900°C some of these changes are not recoverable after subsequent cooling.