Are there new ways to improve the asphalt mixtures' surface functions? For sure! By functionalization process

Abstract

Titanium Dioxide (TiO2) semiconductor material and Polytetrafluorethylene (PTFE) have been applied in the form of nano/microparticles over asphalt road pavements to provide them with new surface functionalities. This is a FUNCTIONALIZATION process that aims to improve the sustainable characteristics of the asphalt mixtures through the photocatalytic, superhydrophobic, and self-cleaning capabilities, which are related to the degradation of hazardous pollutants from the atmosphere (NOx, SO2, among others) for environmental remediation and the cleaning of the road surface (dust, greases, and oils) for the mitigation of the decrease of friction. Thus, in this research work, dispersions containing TiO2 nanoparticles and PTFE microparticles were sprayed over an AC 10 asphalt mixture to coat and functionalize it. To confirm the photocatalysis, super hydrophobicity, and self-cleaning capacities, this smart material performance was evaluated under the degradation of the organic compound Rhodamine B (RhB) as a pollutant model and Water Contact Angle (WCA). The results indicate the photodegradation of the pollutant, confirming the proper functioning of the functionalization process, and a WCA of 150°, proving that the nanoparticles were well dispersed just over the surface of the asphalt mixture. In general, this multidisciplinary research contributes to social and environmental enhancement and enlarges the opportunities for applications of nanomaterials in a very large-scale field such as Civil Engineering. Moreover, it showed that the surface characteristics of the asphalt pavements could be studied and improved not only with a conventional approach based on noise, friction, texture, and rolling resistance measurements but also through a physicochemical approach, as the functionalization processes, using knowledge of Materials Science.