**1. Introduction**

For the past few years, an inspection of reinforced concrete structures with steel rebars has become a subject of research because concrete provides an alkaline environment that is suitable for the spontaneous passivation of steel rebars. These steel rebars act as a reinforcement when tensile loads are applied [1]. But, still, there is a possibility of corrosion in these steel rebars when aggressive chloride ions are

present in the environment [1]. Corrosion in rebars may result in surrounding concrete cracking, reduction in the bond strength of the concrete and the rebars and lowering the combination of strength and ductility [1–3].

Extensive research has been carried out to date on corrosion in steel rebars but a modest solution can be the usage of stainless steels rebars as a partial or complete replacement of the reinforcements in concrete. This solution is economically viable because there may be a higher initial investment cost but this can be compensated by low-repairing cost, less maintenance effort and most importantly long-range services of the designed structures [4]. As per earlier studies, it is well established that austenitic stainless steels can be considered as the common choices for rebars, whereas there is a wide range of applications of the ferritic and the duplex stainless steels that include structural components in the construction industries [1, 5]. However, it cannot be domineered that the austenitic stainless steels are expensive due to the higher content of elements such as Ni and Mo. It has been reported earlier that stainless steel eliminates chances of corrosion but does not rely on concrete when it is subjected to the ingress of chlorides from marine environments. For the last few years, plenty of research has been carried out in search of more economically friendly novel stainless steels as reinforcements [6–12]. It is also true that, since the cost of these steels can be compared with the cost of common black steel reinforcement rather than the cost of highly alloyed stainless steels, the use of low alloyed stainless steel reinforcement has been accepted as economically more convenient [6].

Thermo-mechanical treatment (TMT) has gained researchers' attention for producing high-strength steels with lean chemistry at a reduced cost with excellent mechanical properties [13–16]. In TMT, simultaneous application of heat and deformation causes microstructural refinements [16–18]. These materials are highly used in the construction sectors for the construction of dams, bridges, buildings, flyovers and also in various other structural materials [16, 19]. The durability of these TMT rebars is an immense problem due to corrosion in reinforced concrete structures, which is needed to be minimized as much as possible to enhance the life of that structure. Substandard quality rebars can also cause damage to the towers, buildings and other constructions in the seismic zones. However, in reinforcement concrete, the presence of alkaline solution protects the TMT rebars from corrosion due to the formation of a passive layer over the steel surface [20–22]. However, encountering chloride solution in this structure causes the breakdown of this passive layer. In the coastal and marine areas, excessive level of chloride causes problems of chloride-induced corrosion, thereby creating problems in corrosion resistance of the TMT rebars in the concrete [23–27].

It is well established that corrosion of steel reinforcement bars primarily depends on the stability of different phases that are likely to form in the cement paste and the effectiveness of the oxide layer that forms on the steel bar surface, that is, the passive layer [28]. It has been reported earlier that the concrete pore solutions preserve a strongly alkaline medium due to the significant filling of calcium hydroxide in the concrete pores depending on the hydration reactions of cement. This alkaline environment is suitable for the formation of a stable passive film on the rebar surface and thereby provides significant protection to the steel rebar against corrosive environments [28]. However, chloride-induced corrosion has been reported as a primary source for the local breakdown of this passive film on the surface of the steel bars [28–30]. It is also known that the volume of rebar increases when the corroded product forms on the rebar surface and results in cracks in the concrete, thereby causing failure [27].

*Study on the Perspective of Mechanical Properties and Corrosion Behaviour of Stainless… DOI: http://dx.doi.org/10.5772/intechopen.101388*

This paper primarily emphasizes the study of mechanical and corrosion behaviours of different types of rebars in two different aqueous solutions. It is expected that this study will provide valuable information regarding the improvement in the design parameters and also the life cycle cost calculation of various structures as well as towards the selection of the best-suited rebars for industrial and marine construction purposes.
