Posidonia oceanica used as a new natural fibre to enhance the performance of asphalt mixtures

Fibres are widely used to enhance the performance of the asphalt mixtures. In this paper, the objective is to asses if Posidonia oceanica fibre is a proper additive to improve the mechanical properties of asphalt mixtures. To do so, waste fibres (hemp and polyester) and a commercial fibre were selected. Then, different stone mastic asphalt mixtures were prepared with them. A percentage of 0.3 wt% was considered for the previously studied fibres and 0.3, 0.5, 1, 1.5, 2, 3, 4 and 5 wt% for the algae fibre. To achieve the objective of this research, a complete experimental campaign was prepared and divided in two steps. Firstly, the fibres were characterized and secondly, the resulting fibre-reinforced asphalt mixtures were studied. In the first step, water absorption, thermostability and binder draindown properties were tested for each fibre. Thirdly, the optimum bitumen amount, plastic deformation, bearing capacity and the fatigue life were studied in accordance with the tests described in the European Standards. The results show that algae fibre presents poor properties to achieve the desired effects when they are analyzed alone. However, interesting results are obtained when they are added to the asphalt mixture. These results have been collated with a control mixture to ensure the asphalt mixture performance.