This review addresses the effects of the modifications with nanomaterials, particularly nanosilica, nanoclays, and nanoiron, on the mechanical performance and aging resistance of asphalt mixtures. The desire for high-performance and long-lasting asphalt pavements significantly pushed the modification of the conventional paving asphalt binders. To cope with such demand, the use of nanomaterials for the asphalt binder modification seems promising, as with a small amount of modification an important enhancement of the asphalt mixture mechanical performance can be attained. Several studies already evaluated the effects of the modifications with nanomaterials, mostly focusing on the asphalt binder properties and rheology, and the positive findings encouraged the study of modified asphalt mixtures. This review focuses on the effects attained in the mechanical properties of the asphalt mixtures, under fresh and aged conditions. Generally, the effects of each nanomaterial were evaluated with the current state-of-art tests for the characterization of mechanical performance of asphalt mixtures, such as, permanent deformation, stiffness modulus, fatigue resistance, indirect tensile strength, and Marshall stability. Aging indicators, as the aging sensitivity, were used to evaluate the effects in the asphalt mixture’s aging resistance. Finally, to present a better insight into the economic feasibility of the analyzed nanomaterials, a simple cost analysis is performed.

Pavement management systems (PMSs) are increasingly important tools in the decision-making processes regarding the maintenance and rehabilitation of road pavements. A new optimization model to be used within network-level PMSs is presented in this paper, together with a genetic-algorithm heuristic to solve the model. The model assumes decisions to be segment linked, thus overcoming the principal drawback of the widely used Arizona PMS. The objective of the model is to minimize the expected total discounted costs of pavement maintenance and rehabilitation actions over a given planning time span, while keeping the network within given quality standards. The model was applied to three test problems involving the road network of Coimbra, the third-largest Portuguese city. The results obtained for these problems clearly indicate that the model is a valuable addition to the road engineer’s toolbox.