## 4 Conclusions  
In recent decades, the efficient management of CDW has become one of the major challenges for the construction industry, which is increasingly aware of the need to protect the natural environment and make better use of natural resources. In the present research, progress was made in the state of knowledge of recycled aggregates from waste concrete, and some of their possibilities for the elaboration of masonry mortars reinforced with aramid fiber were shown. More specifically, the mechanical, physical and durability properties of this type of cement mortars were evaluated.  
Regarding the mechanical properties, it was observed that the incorporation of aramid fibers significantly improves the flexural strengths of cement mortars made with recycled concrete aggregate. In addition, the dosages with a cement/sand ratio of 1:3 by weight showed better results than the mixes made with a 1:4 ratio. However, although the incorporation of aramid fibers improves the mechanical strengths of the recycled mortars, they do not reach the flexural strengths of traditional mortars made with natural aggregate. On the other hand, the incorporation of aramid fibers has not significantly improved the compressive strength of the mortars made with recycled aggregate. The microscopy tests carried out show good fiber-matrix adhesion and good cohesion of the material.  
As for the physical properties, it should be noted that the incorporation of aramid fiber has only led to an improvement by decreasing the capillary water absorption in the mortars made with recycled aggregate. On the other hand, the adhesion of mortars with aggregate from concrete waste was reduced by incorporating reinforcement fibers. Aggregate density and surface hardness are not affected by the incorporation of fibers into the mortar matrix. In addition, it was shown that mortars with natural aggregate presented better physical properties and how these properties improve for dosages with higher cement content.  
In the durability tests, there were significant improvements in the mortars made with recycled aggregates that incorporated aramid fibers. More specifically, greater resistance to freeze-thaw cycles was achieved by incorporating reinforcing fibers, increasing the mechanical strength of the recycled mortars and decreasing the loss of mass produced during the freezing test. On the other hand, the shrinkage of mortars with recycled concrete aggregate and aramid fiber also decreases with respect to recycled mortars without fibers. Thus, it can be affirmed that mortars with recycled aggregate and reinforcing fibers have greater dimensional stability and shrinkage decreases to values close to those of traditional mortars made with natural aggregate.  
Finally, it should be noted that this study is part of the contributions aimed at promoting clean production through the efficient use of natural resources, as stated in the European Agenda 2030.  
Conceptualization, D.F. and P.S.; methodology, D.F.; software, D.F. and P.S.; validation, D.F., C.M. and A.M.; formal analysis, C.M.; investigation, D.F.; resources, C.M.; data curation, P.S. and A.M.; writing--original draft preparation, D.F.; writing--review and editing, A.M.; visualization, A.M.; supervision, C.M.; project administration, C.M.; funding acquisition, C.M. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
* Los autores quieren agradecer la colaboracion de la [PERSON], Civ. Eng, de la Bialystok University of Technology por el soporte tecnico prestado en la realizacion de los ensayos de microscopia electronica de barrido (SEM).  
The authors declare no conflict of interest.