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 preventive maintenance is an important tool for extending the service life of the road pavements. Microwave heating seems to be a promising technology for this application, as bituminous materials have the potential to self-repair above a certain temperature. As ordinary asphalt mixture has low microwave absorbing properties, some additives should be used to improve the heating efficiency. In this paper, the effect of adding Electric Arc Furnace (EAF) slag and Graphene Nanoplatelets (GNPs) on the microwave heating and healing efficiency of asphalt mixtures was evaluated. Microwave heating efficiency was assessed by heating the specimens using several heating times. In addition, the electrical resistivity of the mixtures was measured to understand its possible relationship with the microwave heating process. Furthermore, the healing rates of the asphalt mixtures were assessed by repeated Indirect Tensile Strength (ITS) tests. The results obtained indicate that the additions of graphene and EAF slag can allow important savings, up to 50%, on the energy required to perform a good healing process.

The available methods for accelerated ageing simulation in laboratory of compacted bituminous mixtures are often not representative of the ageing mechanisms experienced in the field. The objective of this study was to develop an alternative ageing method, Tecnico accelerated ageing (TEAGE). The method is intended to simulate the ageing of bituminous mixtures under specific environmental conditions by applying watering/drying cycles and ultra-violet (UV) radiation in equivalent levels to those observed in the field during a certain time. In this study a type of mixture was aged using TEAGE and LTOA (long-term oven ageing) methods and then tested for mechanical performance conducting stiffness, fatigue resistance and indirect tensile strength tests. Additionally, the chemical composition of the water used for the watering/drying cycles was analysed and recovered binders were tested for softening point and penetration. TEAGE-aged specimens showed clear evidence of an ageing gradient through the specimens’ depth, substantial reduction in fatigue life (15% reduction in Ԑ₆) and a visible effect on the colouration of the UV exposed surface when compared with LTOA-aged specimens. The overall results and comparison with other studies indicate that TEAGE framework addressed in a more consistent way the ageing mechanisms that could be seen in the field.