###### Abstract  
The valorization of waste fishing trawl (WFT) and waste fishing rope (WFR) fibers in cementitious materials (CMs) has gained attention in recent years; however, the lack of information on the cutting and cleaning techniques for these fibers hinders their widespread commercial utilization. Existing research primarily relies on manual cutting, which proves to be impractical for large-scale production due to its time-consuming nature and lack of industrial feasibility. This research is a component of the VALNET project and introduces an innovative technique that utilizes the cutting mill to convert WFT and WFR into fibers to effectively overcome the constraints of earlier methodologies. By employing a rotor with blades, this apparatus enables efficient and precise cutting of WFT and WFR, eliminating the need for labor-intensive manual cutting. The sustainable cleaning of WFT and WFR was carried out utilizing rain and wind by placing them outside for a certain period of time. The advancements presented in this study provide a pathway for an efficient and scalable vaporization of WFT and WFR fibers in CM. The study focused on analyzing the impact of varying fiber sizes and percentages on the mechanical properties of CM. Different sizes obtained from the cutting machine and different fiber percentages were examined to gain a better understanding of their influence. The fibers obtained by the utilization of a 20 mm sieve yield optimal outcomes, while the incorporation of fibers at a volume fraction of 0.5% yields the most favorable results. Furthermore, the study presents evidence of a noticeable rise in porosity resulting from the incorporation of WFT and WFR fibers, regardless of their size and proportion. Porosity slightly increases as the fiber length increases, but the rise in fiber proportion leads to a significantly greater increase in porosity. fishing trawl fibers; fishing rope fibers; cementitious material; sustainable solution; recycled material; fiber cutting; cleaning +
Footnote †: journal: Applied Sciences  
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reduce waste and preserve natural resources for a more efficient circular economy. Plastic, such as polypropylene, polyethylene, and polyethylene terephthalate, accounts for the majority of marine environment waste [3; 4]. For the reuse of and reduction in marine waste, the development of efficient and environmentally friendly recycling technologies for plastic waste such as abandoned fishing trawls and ropes is crucial. Reusing discarded fishing trawl as a fiber reinforcement in cementitious composites could be one such efficient practice [5; 6; 7]. WFT and WFR have various applications, including carpet tiles, bicycle seats, chair and baggage castors, tool handles, and electrical components [8; 9], as well as non-food contact bottles [10], while its employment in civil engineering is rather recent. Several studies [11; 12; 13; 14] have described the utilization of discarded WFT fibers for the reinforcing of concrete. Concrete is well-known for its brittle nature. As stated in multiple studies [15; 16; 17; 18], different types of randomly distributed fibers can be used to reinforce concrete by preventing or controlling the initiation and propagation of micro- or macro-cracks. The pursuit of sustainable construction is characterized by the conversion of waste materials into practical building components. The widespread utilization of WFT and WFR in the fishing industry frequently leads to their disposal at the end of their functional lifespan, hence worsening the environmental burden [19; 20]. Nevertheless, new investigations have brought to light a distinctive opportunity: the incorporation of this discarded fishing gear in different applications, particularly for reinforcement purposes in cement-based materials [13; 21]. This undertaking, despite its considerable promise, encounters a crucial obstacle--the proficient and productive processing, cleaning, and cutting of these fibers.