## 5 Conclusions  
Based on the research results presented in this study, the following conclusions can be drawn:  
* The addition of recycling agent and/or jute fibers (virgin and NaOH-treated fibers) has a positive influence on the compactability of asphalt mixture with 30% RA content.
* A directly proportional relationship between jute fiber content and air voids was observed. The shorter, 10 mm fibers caused higher air voids content as well.
* The use of jute fibers in reclaimed asphalt mixtures has been shown to produce a significant decrease in ITSR. Mixture with short fibers achieved the lowest ITSR in the mixtures without recycling agents. The NaOH-treated fibers showed better ITSR values. The addition of the recycling agent \"SR\" slightly lowered the ITSR. However, the addition of a higher amount of agent \"SR\" had an opposite effect, although the effect was caused by the lower dry ITS value. On the other hand, the wet/freeze ITS of most mixtures with fibers stayed above the reference level, which can compensate for the low ITSR. The second recycling agent, \"RF\", showed the highest ITSR. Interestingly, mixtures with fibers and without recycling agents achieved higher ITSRs than equivalent mixtures with the recycling agents.
* As predicted, the addition of recycling agents tends to decrease the stiffness modulus, while the addition of jute fibers tends to increase it. Furthermore, fibers that underwent NaOH treatment showed an additional increase in their stiffness modulus. Incorporation of jute fibers led to increased stiffness and to a decline in their thermal susceptibility.
* The addition of virgin jute fibers exhibited the same results in fracture toughness and fracture energy to the maximum force at 0 \({}^{\circ}\)C as the reference mixtures, with a decrease in total fracture energy. On the other hand, only a slight increase in total fracture energy was demonstrated in mixtures that had NaOH-treated fibers added. The addition of recycling agent led to an increase in selected parameters. Mixtures with fibers and recycling agents exhibited the best fracture resistance results. At higher temperature (25 \({}^{\circ}\)C), the surface treatment did not improve the fracture properties. A combination of fibers and recycling agents showed the best results.  
* Similarly to the stiffness modulus, the addition of virgin jute fibers showed higher complex values. Yet, treating the fibers with NaOH resulted in a decrease in the complex modulus across the entire range of frequencies and temperatures.
* Although the effects of adding recycling agent to asphalt mixtures are well known, the addition of recycling agents only showed a similar complex modulus along the low-frequency/high-temperature ranges and higher values along the range of high frequencies/low temperatures. Also, the addition of the recycling agent \"SR\" to treated fibers showed similar values along the entire range. Nevertheless, a decrease in values was achieved in the mixture with virgin fibers.
* Better results were achieved with recycling agents added to RA.  
Conceptualization, P.G. and M.B.; methodology, P.G.; validation, P.G., M.B. and J.V.; formal analysis, P.G. and M.B.; investigation, P.G.; resources, P.G. and J.V.; data curation, M.B.; writing--original draft preparation, P.G. and M.B.; writing--review and editing, P.G., M.B. and J.V.; visualization, P.G. and M.B.; supervision, J.V.; project administration, M.B.; funding acquisition, J.V. and M.B. All authors have read and agreed to the published version of the manuscript.  
This paper was supported by the project No. SGS22/040/OHK1/1T/11.  
Data available on request due to restrictions.  
Authors want to thank [PERSON] for helping with testing and the company JUTEKO s.r.o. for providing the jute yarn sample.  
The authors declare no conflict of interest.