The use of additives for the improvement of the mechanical behavior of high modulus asphalt mixes

• HMAM with optimal fatigue resistance behavior avoiding cracking propagation were obtained.
• HMAM with fibers and crumb rubber increase the resistance to plastic deformation.
• The use of crumb rubber increases the stiffness, bearing and stress distribution capacity.
• HMAM with crumb rubber or fiber is more economical than HMAM with polymer modified binders.

The high stiffness provided by high modulus asphalt mixes significantly decreases the loads transmitted by the traffic to the road foundation whilst at the same time increases their resistance against plastic deformations. Thus, the use of these types of mixtures can be an effective solution in road construction, due to the fact that they can reduce the thickness of the pavement, saving economic and material resources. Nevertheless, in some cases this high stiffness constitutes a drawback because it could reduce the fatigue resistance offered by these materials, leading to a premature appearance of cracks in the pavement, which decreases its service life. Due to this fact, the use of high modulus asphalt mixes is limited, especially in cold climates. In order to solve this problem, this research has been focused on the improvement of the mechanical performance of high modulus asphalt mixtures through the use of additives (crumb rubber and acrylic fibers), which could increase their fatigue resistance by maintaining the stiffness required. Different tests have been carried out under different temperatures for the mixtures assessment. The results obtained have shown that the incorporation of these additives could lead to a better mechanical behavior of high modulus asphalt mixes, and thus it could improve their performance.