## 3 RR-FRC Under Chloride Ingress
### Effects on Load-Bearing Capacity of RR-FRC
However, despite the higher reduction in the load-bearing strength of uncracked RR-SFRC compared to RC at 180 days, the load-bearing strength of RR-SFRC was still higher than that of RC in relative terms. [PERSON] and [PERSON] [72] investigated the effects of recycled-type-steel fibres (RTSF) and virgin-steel fibres on the chloride-induced corrosion of rebar. The study considered uncorroded beams and beams exposed to accelerated corrosion via direct impressed current (700 mA) to achieve the target corrosion level. Four corrosion levels were considered in the study: \(\eta\) = 0%, 2%, 7% and 10%. Figure 7 shows the recorded values of \(F_{y}\), \(F_{\mathrm{u}}\), displacement at yield (\(\Delta_{y}\)) and ultimate displacement (\(\Delta_{\mathrm{u}}\)) during loading in 3 PBT until failure. All concrete types showed signs of degradation of the load-bearing capacity with the increase in corrosion level. Relative to the uncorroded specimen, the loss was highest in the case of RR-SFRC (16%), followed by RR-RTSFRC (11%), whereas RR-HyFRC even showed a slight increase in \(F_{\mathrm{u}}\) (2%). A similar trend was observed for loads corresponding to yield and ultimate deflection. [PERSON] and [PERSON] [40] investigated the effects of corrosion inhibitors on structural performance. In one scenario, beams were exposed to a 5.1% NaCl solution, whereas in another scenario, TEA was added to the NaCl solution. The increase in ultimate load in RR-SFRC specimens, particularly with the addition of TEA, emphasises the potential of combining SF with chemical inhibitors to enhance the durability and structural performance of concrete exposed to aggressive chloride environments. In this context, for the same load level (45 kN), the crack widths of RR-SFRC elements were 56% (without the addition of TEA) and 70% (with the addition of TEA) lower than in the case of RC. Furthermore, both types of RR-SFRC had a 17% higher ultimate load compared to the RC element. Figure 7: _Cont._  
[PERSON] and [PERSON] [73] used direct current (13 V) to accelerate chloride-induced corrosion and to investigate bond strength and the loss of load-bearing capacity of the corroded specimens. Three corrosion levels were considered: 0% (uncorroded, reference specimens) \(\eta\) = 6%, 10% and 16%. It was observed that the time required to achieve the target corrosion level was higher for RR-SFRC specimens compared to RC beams by 44%, 54% and 61% for corrosion levels of 6%, 10% and 16%, respectively. In 4 PBT, RR-SFRC beams exhibited superior performance compared to RC beams. [PERSON] et al. [75] used a constant direct current (1 A for 24 days) to accelerate chloride-induced corrosion. At the end of the exposure period, all elements were subjected to 4 PBT until failure, and values of the applied load and corresponding deflection were recorded. The results showed that the corroded beams exhibited a 28.7% lower maximum load compared to those uncorroded (Figure 8), implying a clear effect of the degradation of rebar on the structural performance. Both corroded RR-SFRC elements failed due to concrete crushing with reinforcement yielding, which the authors attributed to the presence of fibres and their contribution to the enhanced ductility of concrete elements. The average loss of mass in the corroded specimens was 6.2%, 16.4% and 24.1% for reinforcement in compression, tension and stirrups, respectively, indicating the effects of crack orientation and stress state in the element on the corrosion of rebar. In another study stemming from the same experimental campaign as in [80], [PERSON] et al. [79] investigated structural performance in terms of the load-bearing capacity. In absolute terms, the load capacity of corroded RR-FRC beams was determined to be higher than in the case of RC (Figure 9). Corroded RR-SFRC exhibited a similar loss of rotational capacity as RC, whereas slight improvements were observed for RR-PVAFRC and RR-HyFRC.