## 6 Conclusions  
In this research, the impact of SFs on the cracking in RCARC beams was evaluated. The research involved tests on 27 RC beams. In the specimens, SFs were mixed at different contents (0%, 1% and 2%). In the tests, the mid-span load-displacement relationship and the crack propagation and widths were measured. The obtained laboratory results were also compared with the proposed equations of CSA S474 (2004), NS 3473E (2003), EC2-04 (2004), CEB-FIP (2010) and ACI 224R-14 (2014). According to the achieved outcomes, the following conclusions could be drawn:  
1. RCA is an appropriate material that can be used instead of natural materials in concrete for buildings.
2. The bending capability increased by increasing the RCA content. Additionally, using 100% RCA decreased the load drop after the maximum bearing capability point, while in the specimen without RCA, the bending resistance abruptly dropped after the maximum load.
3. SFs enhanced the maximum bearing capability and using this material with RCA enhanced the flexural resistance of the RCARC beams compared to the control specimens.
4. Enough shear rebars must be provided over the beams to control the crack width and propagation but SFs can enhance the bending performance of RCARC beams without shear rebars.
5. In addition to increasing the bonding between the rebars and concrete, cracks developed less when SFs were used. Therefore, specimens with a 2% SF content deformed with more ductility and did not collapse quickly.
6. Adding SFs to concrete improved the bending performance of the specimens. A minimum number of shear rebars should be provided but SFs should be used in the specimens.
7. In specimens with no shear rebars, CSA properly predicted the crack width, unlike CEB. On the other hand, all codes presented an appropriate equation to predict crack width in specimens with different SF and RCA contents.
8. In cylindrical specimens under pressure, by adding SFs, cracking occurred only in the concrete surface. Furthermore, due to RCA's higher and more angulated specific surface compared to NCA, RCA was better impregnated with cement paste, which prevented the complete disintegration of the sample.
9. In cylindrical specimens under indirect tensile stresses, a specimen with no SFs broke into two parts but using SFs prevented them from separating. The use of RCA increased the tensile strength of the specimen.
10. SFs had a significant effect on reducing the initial crack's width but there was no significant difference when 1% and 2% SFs were used. On the other hand, using 1% SFs did not have a considerable effect on reducing the initial crack's width when 100% RCA were used.  
Conceptualization, M.G. and J.d.B.; Formal analysis, M.G.; Investigation, A.K. and H.R.C.; Methodology, A.K. and H.R.C.; Software, M.G.; Supervision, M.G. and J.d.B.; Writing-original draft, A.K. and H.R.C.; Writing-review & editing, J.d.B. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors wish to thank the CERIS (Civil Engineering Research and Innovation for Sustainability) research centre and the FCT (Foundation for Science and Technology).  
The authors declare that they have no conflict of interest.  
The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.