Behaviour of Reinforcement in RCC Structure when Subjected to Fire

As we all aware that hazards of major fires and fire mishaps are increasing day by day in structures. Therefore evaluation, rehabilitation and repair of structures damaged by fire have become a newsworthy. Effect of fire is most serious potential risk to most of RCC STRUCTURE. In todays world concrete is most widely used in construction field. So, for researchers to make concrete fire resistant has become tropical interest. In many countrys several researchers did researches on this topic. In this area Research and developmental efforts are continuously being carried out and other disciplines are also trying to research on this topic. The reality of actual life issue are expressed which gives us real feeling in this topic. From this research we would be familiar on the absolute approach for the rehabilitation of structure damaged due to fire. Also express a particular evaluation and procedures by conducting some techniques known as NDT, and recovering method. To find out the effect of the fire on reinforcement steel bars we performed some experiment on 6 samples, each bar heated to 150, 350, 650, 950 centigrade temperature. After heating all samples are rapidly cooled in water by quenching and under air cooling also by normal process. Observed properties of samples changed (mechanical) by using universal testing machine (UTM) and grain size and grain structure is studied by scanning electron microscope (SEM) that is known as microscopic study. We conclude that more than half of RC structures are restorable which are damaged due to fire. As the temperature increases mechanical properties of material decreases. Analysis of structure in fire conditions is done by testing the properties of the composing materials, steel and concrete, at elevated temperature. By the effects of heating, steel and concrete have certain change in their strength, physical properties, and stiffness and some are repairable and some not after consequent cooling. The reinforcement bars when exposed to elevated temperature above 950C was observed that ductility reduced when rapidly cooled by water. The bar which is cooled under normal atmospheric conditions the impact of temperature on ductility is not high. Mechanical properties can be altered without changing the chemical constituent by heating the reinforcement bars.