Advanced Self-Healing Asphalt Composites in the Pavement Performance Field: Mechanisms at the Nano Level and New Repairing Methodologies

In an effort to give a global view of this field of research, in this mini-review we highlight the most recent publications and patents focusing on modified asphalt pavements that contain certain reinforcing nanoparticles which impart desirable thermal, electrical and mechanical properties. In response to the increasing cost of asphalt binder and road maintenance, there is a need to look for alternative technologies and new asphalt composites, able to self-repair, for preserving and renewing the existing pavements. First, we will focus on the self-healing property of asphalt, the evidences that support that healing takes place immediately after the contact between the faces of a crack, and how the amount of healing can be measured in both the laboratory and the field. Next we review the hypothetical mechanisms of healing to understand the material behaviour and establish models to quantify the damage-healing process. Thereafter, we outline different technologies, nanotechnologies and methodologies used for self-healing paying particular attention to embedded micro-capsules, new nano-materials like carbon nanotubes and nano-fibres, ionomers, and microwave and induction heating processes.Authors wish to thank Spanish Ministerio de Ciencia e Innovación for grants IPT-2011-1359-420000 and MAT2010-17091

Asphalt mixes containing carbon nanotubes modified bitumen. Design and properties

Se describe el desarrollo y estudio de las propiedades reológicas y de conductividad eléctrica de betunes modificados con nanotubos de carbono. Esta modificación transforma a estos materiales en semiconductores eléctricos, lo que abre un nuevo abanico de posibilidades de uso a un material que, habitualmente, se comporta como un aislante eléctrico. Como muestra de estas nuevas aplicaciones se presenta el diseño y estudio de mezclas asfálticas con ligantes modificados con nanotubos, que conceden a la mezcla propiedades de autorreparabilidad mejorada debido al calentamiento producido por absorción de microondas. Los resultados expuestos forman parte de los trabajos realizados durante el desarrollo del proyecto MAMCE financiado por el Ministerio de Economía y Competitividad dentro de su convocatoria lnnpacto 2011.The development and study of the rheological and electrical properties of bitumen modified with carbon nanotubes is exposed. This modification transforms the bitumen into electrical semiconductor material, which opens a new range of possibilities of use to a material that, usually, acts as an electrical insulator. As an example of these new applications, design and study of asphalt mixes made with carbon nanotubes modified binders conferring improved self-healing properties to the mixture by microwave absorption are presented. Results showed in this paper have been obtained in the development of the MAMCE project, granted by the Spanish "Ministerio de Economía y Competitividad", call "lnnpacto 2011"