## 3 RR-FRC Under Chloride Ingress
### Effects on Load-Bearing Capacity of RR-FRC
The loss of reinforcement mass was higher in elements with wider cracks and in cyclically loaded specimens compared to specimens under sustained loads. In the campaign led by [PERSON] et al. [83], apart from the impact on the initiation and propagation, the authors observed a difference in the degradation of load-bearing resistance. For RC elements, this value was determined to be 3%, whereas for RR-HyFRC, it was 9%; however, in absolute terms, the load-bearing capacity of corroded RR-HyFRC was 28% higher than that of corroded RC (Figure 10). Figure 7: Structural behaviour of specimens in 3 PBT: (**a**) Yield load; (**b**) Ultimate load; (**c**) Deflection at yield; (**d**) Ultimate deflection [72]. [PERSON] et al. [84] observed the impact of corrosion on the load-bearing performance of concrete elements. The flexural stiffness in corroded RC specimens was found to be 33% lower than that in uncorroded reference specimens, and the load corresponding to the opening of flexural cracks in corroded RC elements was 35% lower than in uncorroded beams (Figure 11). In contrast, in corroded RR-HyFRC elements, the load at which flexural cracks opened and flexural stiffness remained similar to the reference specimens. Figure 8: Structural performance of uncorroded (B1.1-NC) and corroded (B2.1-C and B3.1-C) RR-SFRC beams in the study by [PERSON] et al. [75]. Figure 10: Load-bearing capacity of (**a**) uncorroded RC and RR-HyFRC elements; (**b**) corroded RC and RR-HyFRC elements [83]. Figure 9: Recorded load at the onset of reinforcement yielding of RC (PL), RR-SFRC (ST), RR-PVAFRC (SY), RR-HyFRC (HY). NC—uncracked, UN—unloaded, CY—cyclically loaded, LO—loaded [80]. [PERSON] et al. [86] investigated the effectiveness of using ductile-fibre-reinforced cementitious composite (DFRCC) to partially substitute PC to enhance the durability and structural performance of concrete beams. The investigation was performed on two series of beams identical in all aspects, except for the partial substitution of PC in the tensile zone with DFRCC in the second series, thus labelled RR-HyFRC. An impressed direct current of 8 V was used to accelerate corrosion. The loss of load-bearing capacity (in 4 PBT) relative to the reference (uncorroded) specimens was 13% and 8% for RC and RR-HyFRC, respectively. In absolute terms, corroded RR-HyFRC beams had an 18% higher \(F_{\text{u}}\) and a 22% higher \(F_{\text{y}}\) load compared to corroded RC beams. A higher loss of reinforcement mass in the corroded specimens was observed in RC (10.1%) than in RR-HyFRC elements (8.3%). By using [PERSON]'s law to calculate the loss of mass due to corrosion, the study determined that RR-HyFRC elements would require 70% more time to achieve the same amount of corrosion damage as RC elements. [PERSON] et al. [74] observed a change in the failure mode from ductile to brittle in the case of corroded RC elements. However, in all the remaining specimens, including corroded RR-SFRC, the failure mode remained ductile. The loss of load-bearing capacity decreased with the increase in \(V_{\text{f}}\), with the highest observed loss of 18.5% in RC elements, followed by 16.9% and 13.7% in RR-SFRC (0.5%) and RR-SFRC (1.0%), respectively. [PERSON] et al. [89] used impressed current (constant current density of 250 \(\mu\)A/cm\({}^{2}\)) to obtain a corrosion of rebar equal to \(\eta=5\%\) in RC and three different types of RR-SFRC. The load-bearing capacity was assessed using 4 PBT. The results demonstrated a clear relationship between fibre content and the extent of load-bearing capacity degradation. Higher fibre content mitigated the severity of degradation, with corroded specimens containing a fibre volume fraction \(V_{\text{f}}=1.5\%\), achieving the same load-bearing capacity as uncorroded reference specimens with the same fibre content. Additionally, the fibres enhanced the ductility of corroded RR-SFRC beams compared to corroded RC beams, with specimens containing \(V_{\text{f}}=1.5\%\) exhibiting 50% greater ultimate deflection than RC beams.