# Enhanced Performance of Concrete Dispersedly Reinforced with Sisal Fibers
## 3 Results and Discussion
### Analysis of the Structure of Normal Weight Concrete, Dispersed Reinforced with Sisal Fibers  
This analysis was carried out to establish the relationship between the structure of the material and the strength characteristics of concrete. For the study, concrete samples with a sisal fiber content of 1% were selected, which were previously tested for compression. Figure 14 shows a photo of the structure of concrete samples reinforced with sisal fibers. Figure 14: Photographs of the structure of concrete samples with a content of sisal fibers 1%: (**a**) with 4\(\times\) magnification; (**b**) with 6\(\times\) magnification; (**c**) with 8\(\times\) magnification; (**d**) with 10\(\times\) magnification. Figure 14 shows that the structure of the samples reinforced with dispersed sisal fibers is loose after destruction and has many cracks; however, unruptured fibers restrain the concrete matrix due to the bridging effect. The obtained images indicate that the dispersed fiber reinforcement with sisal fiber reduces the number of cracks in the structure of the cement stone, restrains their propagation and, due to the bridging effect of sisal fibers, binds the concrete matrix. However, due to the high water absorption of sisal fibers, the formation of cracks is observed along the area of contact of the cement paste and fiber, which reduces the anchoring of fibers in concrete. Conducting a comparative analysis of the results obtained in this study with the data of other authors, we can conclude that we have achieved an improvement in the increase in the strength characteristics of the resulting fiber-reinforced concrete. The authors of studies [11; 19; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 33; 35; 39; 41; 42; 43; 45] obtained increases in the strength characteristics of concrete aged 28 days from 5% to 30% due to fiber-dispersed reinforcement of concrete with sisal fibers. The technology and recipe recommendations used by the authors of the presented study gave an increase in the strength characteristics of concrete at the age of 28 days from 22% to 33%. Moreover, with the help of the stress-strain curves built based on experimental studies of the obtained fiber-reinforced concrete compositions, improvements in the deformation characteristics were also revealed. Considering the above, we can confidently say that this study has both an applied technological nature and offers significant prospects in the field of economic and environmental efficiency. Further work is planned in the field of research development in the ecological and economic mainstream. The first task of the study was to prove the possibility of full utilization of agricultural waste, namely sisal fibers, in the construction industry. The fundamental possibility of using sisal fibers as a fiber-reinforcing element for concrete was proved. Rational dosages of such fibers were determined, and their compatibility with cement stone and other components that create a phase boundary with sisal fibers was studied. In this regard, it was important not only to prove the possibility of fiber reinforcement, but also to substantiate its technical, economic and environmental efficiency. In particular, it was determined that the demonstrated results of environmentally friendly concretes based on sisal fiber are not inferior to analogues of concretes reinforced with expensive artificial types of fibers, such as polypropylene, basalt fibers and, to some extent, steel and glass fibers [63; 64; 65; 66; 67; 68]. The performed literature review, as well as the analysis of the obtained results provide a basis for the development of a laboratory method and factory technology for the production of concretes with sisal fibers. Its increases in strength characteristics, as well as positive trends in the change in deformation characteristics, suggest that it is necessary to focus in more detail on finding the maximum compatibility of the fiber and the concrete matrix.