## 4 Flexural Behavior
However, certain empirical equations of the critical parameters were modified to better suit different types of matrix materials. Furthermore, the average crack spacing and coefficient for the strain distribution of the FRP bars were established through regression analysis of experimental data. As a result, the applicability of this modified model is confined exclusively to ECC beams reinforced with sand-coated CFRP bars under service limit conditions. [PERSON] et al. [22] conducted a four-point bending test to investigate the correlation between reinforcement strain and crack width. The assessment of crack width was performed using a predictive formula that integrated the proposed bond model along with a fiber-bridging law. The findings indicated that the number of cracks increased with an increase in fiber-volume fraction in FRCC. Furthermore, the relationship between reinforcement strain and crack width derived from the bending test was consistent with the predictions made by the formula. [PERSON] et al. [39; 46] examined how synthetic fibers affect the short- and long-term flexural performance of GFRP beams, comparing their findings with established guidelines. Their study revealed that the addition of fibers led to reductions in tensile creep, compressive creep, and shrinkage strain by 15%, 22%, and 26%, respectively. Additionally, deflection decreased by 25% to 43% depending on the fiber-volume fraction used. The experimental outcomes were assessed against prediction models for both short-term and long-term deflection as outlined in ACI 440 [33], ISIS [47], and CSA [31], which were found to be inaccurate for FRC beams. While the creep and shrinkage strain prediction models from Eurocode 2 [48] and ACI 209 [49] aligned well with the compressive strain, they tended to overestimate shrinkage strains. The authors suggested that further research and adjustments to current methodologies are necessary to make them suitable for FRC beams reinforced with FRP bars. Figure 11: _Cont._  
[PERSON] et al. [42] proposed a model for estimating the flexural resistance factors for FRC beams that are reinforced with GFRP bars. To assess the reliability of this model, a Monte Carlo simulation was employed for calibration. The analysis utilized data from three previously published studies, [PERSON] et al. [50], [PERSON] et al. [51], and [PERSON] et al. [52], which were based on experimentally obtained results for FRC reinforced with GFRP bars. The target reliability index used in this assessment aligned with that of the current design code specifications. The estimated flexural resistance factors were found to range between 0.72 and 0.95. [PERSON] et al. [40] and [PERSON] et al. [41] studied basalt FRC members reinforced with GFRP bars and reported that basalt microfibers (BMF) enhanced the flexural performance of GFRP reinforced members in terms of load carrying capacities, cracking, and ductility. Reinforced concrete structures are designed and maintained in adverse environmental conditions, where they are subjected to cycles of drying and wetting, freeze-thaw phenomena, carbonation, and chloride ingress. These factors contribute to the corrosion of the steel reinforcement and the deterioration of the concrete matrix. Consequently, these structures may not fulfill the requirements of the ultimate limit state and the serviceability limit state when exposed to corrosive environments [53]. As discussed in the introduction, FRP-reinforced FRC structures can resist this harsh environment. [PERSON] et al. [38] conducted experimental and analytical investigations on the flexural behavior of FRP-reinforced ECC specimens subjected to freeze-thaw cycles. They developed formulas for the balanced reinforcement ratio, moment capacity, and stiffness of FRC-reinforced ECC specimens, based on ACI 440 [33] and GB 50608 [45].