es menor de 2 cm. Para ello, la mesa vibrante se modifica, quitando las barras e incorporando dos tamices. El tamiz superior tiene un tamaño de luz de malla de 3 cm y el inferior de 1 cm, por lo que la fibra deseada queda retenida entre los 2 tamices. En el tamiz superior queda retenida la fibra más grande, la cual es recogida a través de un canalón en un contenedor y será introducida de nuevo en el molino para obtener fibra más pequeña. Por último, la fibra que pasa el segundo tamiz es microfibra, y también es recogida y utilizada para la aplicación elegida (Figura 8). Una vez valorizado todo el residuo recogido, se obtienen 16 toneladas de fibra de vidrio de un tamaño menor de 2 cm, con lo cual se obtiene un rendimiento del prototipo de reciclado del 59%. Esta fibra de vidrio ha sido incorporada en diferentes porcentajes en mezclas asfálticas, los cuales han sido seleccionados previamente mediantes diversos ensayos, siendo 0,50%, 0,75%, 0,85%, 1,00% y uno de referencia sin fibra. Con estos porcentajes se han asfaltado cinco tramos de carretera de 300 metros cada uno de ellos (Figura 9 y Figura 10). Estos tramos asfálticos serán monitorizados durante un año y se espera que se mejoren sus propiedades mecánicas. Por lo tanto, gracias al proyecto LIFE REFIBRE se ha diseñado y construido un prototipo innovador de reciclado mecánico con el que se han conseguido reciclar palas de aerogenerador fuera de uso, y obtener las fibras de vidrio por las que están compuestas. A estas fibras se las ha dado un segundo uso de vida en una nueva aplicación, su introducción en aglomerado asfáltico para mejorar sus propiedades mecánicas, consiguiendo cerrar su ciclo de vida. components is obtained. However, in order to incorporate it into the asphalt mix, it must be made smaller in size. Therefore, it is once again sent to the hammer mill to carry out the third stage of the process, which consists of secondary shredding to reduce the size of these fibres. To achieve this, the operating conditions of the mill are once again optimised, as longer retention times and greater striking force are required. In the final stage, screening is carried out to separate the fibres into different sizes, because the ideal fibre size is less than 2 cm. For this purpose, the vibrating table is modified, the bars are removed and two sieves are fitted. The upper sieve has a mesh size of 3 cm and the lower sieve a mesh size of 1 cm, meaning that the desired fibre is retained between the two sieves. The upper sieve retains the larger fibres, which are sent by means of a chute to a container and once again put through the mill to obtain smaller fibres. The fibre that passes through the second sieve is microfibre and it is also collected and used for the chosen application (Figure 8). When all the collected waste has been recovered, 16 tonnes of glass fibre of less than 2 cm in size is obtained, meaning that a recycling efficiency of 59% is achieved with the prototype. This glass fibre has been incorporated into asphalt mixes in different percentages, which were previously selected based on different tests. The following percentages were chosen: 0.50%, 0.75%, 0.85%, and 1.00%, in addition to a benchmark sample without glass fibre. Five sections of road, each with a length of 300 metres, have been asphalted using mixes with these percentages of glass fibre (Figures 9 and 10). These sections of road will be monitored over a one-year period and it is expected that their mechanical properties will be enhanced. Therefore, the LIFE REFIBRE project has enabled the design and construction of an innovative mechanical recycling prototype, with which it has been possible to recycle end-of-life wind turbine blades and recover the glass fibres they contain. These fibres have been given a second life in a new application, i.e., they have been incorporated into asphalt mixes to improve the mechanical properties of these mixes, thereby closing their lifecycle loop. Figura 9. Asfaltado tramo demostrador con fibra de vidrio incorporada. | Figure 9. Demonstration section with asphalt mix featuring incorporated glass fibre. Figura 10. Parte del tramo demostrador. Figure 10. Part of the demonstration section. Alicia Aguado Pesquera Investigadora de la división de Agroalimentación y Procesos de CARTIF. Researcher at the CARTIF Division of Agro-food and Processes. Gestión y tratamiento de residuos | Waste Management & Treatment FuturEnviro | Octubre October 2019 www.futurenviro.es 55
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