## 4 Conclusions  
Composite materials are certainly materials of the future but also of the present. Application of the fiber polymer materials provides great opportunities in repair and strengthening of the RC structures, thus extending their service life [33].  
Experimental testing of six two-span continuous beams made of self-compacting concrete strengthened with fiber reinforced polymer (FRP) materials was done in this research. The influence of the method of strengthening, type of the FRP material and position of the strengthening on the flexural behavior of the examined beams were analyzed. Based on all of the above, general conclusions can be summarized:  
1. The use of FRP materials in strengthening of RC continuous beams, even with a small amount of additional reinforcement, can considerably increase their load-bearing capacity. An increase of 22-82% in the load-bearing capacity of the strengthened beams compared to the control beam was achieved.
2. The highest increase of the load-bearing capacity was in the beams strengthened both in the negative moment zone above the middle support and in the positive moment zones in the spans, and it ranges within 50-82% depending on the type of FRP reinforcement (glass and carbon) and the method of strengthening (EB and NSM).
3. Strengthening with CFRP materials results in a higher failure load, but the price of these materials is considerably higher compared to GFRP materials so in each individual case, it should be assessed which material is more adequate.
4. The use of FRP materials also influenced the increase of the yielding load which was in the range from 14% to 100% compared to the yielding load of the control beam.
5. With the increase in the amount of FRP reinforcement, it is noticeable that there is a decrease in the deformability or ductility of reinforced beams, which is one of the main disadvantages of using FRP reinforcement.
6. The failure modes of the strengthened beam with higher percentage of FRP reinforcement were brittle with separation of the concrete protective layer and before fully utilizing the tensile strength of the FRP material. The lowest efficiency was observed in the beam strengthened by the EB method due to the separation of the tapes.
7. Debonding of the FRP system in the beams strengthened in the same manner occurred earlier with the EB method, so the efficiency and utilization of the tensile strength of the FRP reinforcement is higher with the NSM method.
8. The basic disadvantages of the NSM method compared to the EB method are the groove size for installing the FRP bars and the higher price, which lead to the conclusion that the assessment of which method is more adequate should be made on a case by case basis.  
In further experimental research, the use of narrow strips instead of bars in the NSM method, given the smaller size of the required gap in the concrete, can be analyzed. Further, the numerical model of the examined continuous beams using the finite element method should be made, validated and verified with experimentally obtained results.  
Conceptualization, Z.P. and B.M. ([PERSON]); methodology, Z.P. and B.M. ([PERSON]); software, A.Z. and P.P.; validation, S.R. and B.M. ([PERSON]); formal analysis, B.M. ([PERSON]); investigation, P.P., S.R. and D.Z.; resources, S.R. and B.M. ([PERSON]); data curation, A.Z.; writing--original draft preparation, Z.P. and B.M.; writing--review and editing, S.R. and D.Z.; visualization, B.M. ([PERSON]); supervision, B.M. ([PERSON]) and D.Z.; project administration, Z.P. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.