Evaluación de la durabilidad a fatiga de mezclas semicalientes con adición de zeolita natural y RAP.

This paper shows the results of an evaluation for fatigue deterioration in warm mix asphalt mixtures (WMA) and WMA with the addition of recycled asphalt pavement (RAP) which are compared with a conventional reference mixture (HMA). Fatigue failure is one of the most frequent deterioration mechanisms in flexible pavements. It is characterized by the production of an initial micro cracking, and the repetition of loads produced by the traffic, the deterioration progresses until producing the fatigue fail of the pavement. For the experimental study, five asphalt mixtures developed in the project IDeA / CONYCIT, called " Desarrollo y Diseno de Mezclas Asfalticas de Mayor Eficiencia Energetica y Bajo Impacto Ambiental " were evaluated, which two are asphalt mixtures with different percentages of addition of natural zeolite 0.3% and 0.6% and three are recycled asphalt mixes with 10%, 20% and 30% RAP addition cups. All mixtures fulfill the Chilean standard. To complete this study, the fatigue damage is evaluated by means of the fatigue indirect tensile, UNE-EN 12697-24:2004+A1:2007 standard. Additionally, the stiffness modules and density whose procedures are regulated by the UNE-EN UNE-EN 12697-26:2012 and the Chilean standard MCV8 8.302.38 were evaluated respectively. When the fatigue laws for each evaluated mixtures were obtained, a durability analysis of pavements was realized. For this, a type pavement structure composed of wearing asphalt layer, granular layers and subgrade was proposed. Different pavement thicknesses were evaluated by the mechanical empirical design method determining the asphalt mixtures durability in these pavement structures. The results showed that using the WMA with the addition of natural zeolite, similar performances were obtained in relation to conventional HMA mixture. Different results obtained by recycled WMA because of higher stiffness compared to HMA. As a result, it is recommended to use this type of mixtures, similar to the high modules mixtures, in intermediate layers of pavement structures to increase the duration to fatigue of the pavement.