Behaviour of Deteriorated Reinforced Concrete Columns under Elevated Temperatures

Corrosion of reinforcement is the primary causal factor for premature deterioration of reinforced concrete (RC) structures. Exposure to elevated temperatures such as fire events can further exacerbate the integrity of the structure. The cumulative impact of the presence of corrosion and exposure to elevated temperatures on the behaviour of short RC columns constitutes the objective of present study. An experimental investigation was conducted to evaluate the effect of the degree of corrosion on the behaviour of RC short columns exposed to elevated temperatures. Total twenty-one RC short square column specimens were cast. Twelve columns were corroded to 10% and 20% degree of corrosion in accelerated corrosion process. Subsequent to completion of the corrosion process, columns were subjected to elevated temperature exposure (500 degrees C and 800 degrees C) in an electric furnace. Uncorroded specimens underwent the same thermal exposure regime. Afterwards uniaxial compression test was carried out. The results indicated that corrosion had pronounced effect on the ductility and residual load-bearing capacity of the columns upon exposure to high temperatures. Significant loss of cross section in the transverse reinforcements led to compromised lateral restraint in corroded columns. Columns with 20% corrosion had brittle failure. Role of stirrup design and layout in this aspect should be further investigated. Further research is recommended for detailed studies on the heat transfer mechanism in corroded RC columns when exposed to high temperatures.