Fatigue cracking is one of the primary distresses in asphalt pavements. This study presents a method to characterize fatigue resistance of the fine portion of the asphalt mixture using the dynamic mechanical analyzer (DMA). Three mixtures were characterized in controlled-strain and controlled-stress modes of loading. The new method has several advantages as it requires reasonable testing time, uses a small amount of material, utilizes fundamental properties of the mixture, and is able to unify the results from controlled-strain and controlled-stress modes of loading. The unified method relies on identifying the different mechanisms of energy dissipation during fatigue cracking that are related to changes in the phase angle, changes in stiffness, and development of permanent deformation during the fatigue damage process. Two fatigue damage parameters are derived in this paper. The parameters are shown to have reasonable and lower coefficients of variation than conventional parameters such as number of loading cycles to failure and cumulative dissipated energy.

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Road pavements are designed to withstand road traffic and weathering actions while ensuring comfortable and safe riding conditions as well as low costs and damage to the environment. When a road pavement has additional abilities or reacts to an external stimulus, it is considered to be smart and multifunctional. Examples of such abilities that have been investigated in asphalt mixtures are photocatalytic, superhydrophobic, self-cleaning, deicing/anti-icing, self-healing, thermochromic, and latent heat thermal energy storage abilities. These abilities are developed using different materials such as nano/microparticles (including semiconductor materials and microcapsules), fibers, phase change materials (PCMs), and dyes, often using dissimilar techniques such as spray coating, volume incorporation, spreading, and asphalt binder modification. Owing to their large surface areas, road pavements are true recipients for large amounts of nano/micromaterials, and consequently, act as important "tools" to stimulate an emerging sector related to the scale of production of materials in the form of nanoparticles. Moreover, smart and multifunctional road pavements can be included in the domain of clean technology (e.g., photocatalytic pavements that promote the environmental depollution of NO x -type gases emitted as vehicle exhaust gases). In this context, they can contribute to materializing the transition to a novel socioeconomic model known as "Green Recovery" that is environmentally friendly, sustainable, and inclusive. This model is a very important path toward economic and employment recovery, a vision to which many countries are strongly committed. Therefore, this work reviews new capabilities imparted to asphalt mixtures and provides recommendations.

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