BEHAVIOUR OF DETERIORATED REINFORCED CONCRETE STRUCTURAL ELEMENTS UNDER ELEVATED TEMPERATURES

Abstract

Reinforced concrete (RC) structures are susceptible to exposure to ever-increasing hostile environmental conditions, such as chloride attack, carbonation, sulphate attack; and hazardous events such as fire. Corrosion of the reinforcing steel is the primary causal factor for premature deterioration of RC structures, a fire event in such a scenario can further exacerbate the integrity of RC structures. The major sources responsible for corrosion of steel are chloride attack (due to exposure to saline environment, usage of deicing salt, etc.) and carbonation. Current fire performance criteria for reinforced concrete structural elements pertain to pristine specimens, however steel reinforcement corrosion is prevalent in real-world RC structures. Every year, the global community incurs billions of dollars in costs due to the problems related to corrosion. Thus, it becomes imperative to study the role of existing deterioration on the behaviour of RC structural elements upon exposure to elevated temperatures. Plenty of research has been carried out to evaluate the individual detrimental effects of steel reinforcement corrosion, as well as elevated temperature exposure on the mechanical properties of RC beams and columns. However, the combined effect of presence of corrosion and elevated temperature exposure on the behaviour of RC beams and columns is seldom investigated in the literature. The present study tries to address this research gap. Furthermore, in case of elevated temperature exposure to concrete, while the mechanical properties of concrete have been extensively investigated in the literature, still there is considerable lack of research related to durability properties of concrete. Higher temperatures can lead to more significant declines in properties associated with durability compared to compressive strength. Codes and guidelines addressing the design and repair of concrete structures subjected to high temperatures frequently overlook durability concerns. These inadequacies in the guidelines can potentially jeopardize the long-term durability of concrete structures exposed to elevated temperatures.