Self-healing asphalt

In this TEDxTalk Eric gives a demo of a new type of asphalt made with simple materials, that results in astonishing features.

The problem:
After some years, asphalt binder is degraded by environmental factors, especially due to UV-radiation from the sun, until it loses the ability to bind the surface particles together. This results in cracks which allow damaging moisture into the lower pavement levels, creating surface roughness, pot holes, degradation and eventual structural failure. At present, there are no solutions to close cracks in the pavement. Occasionally, when signs of ageing are visible, a sealant that protects asphalt surfaces from environmental degradation and moisture penetration is applied to the surface. These procedures can increase the lifetime of asphalt for several years before rehabilitation or reconstruction is required, but they have the disadvantage that they only work in the first centimeters from the surface and can reduce sliding resistance.

In many studies it has been demonstrated how it is possible to make asphalt or concrete conductive by adding electrically conductive fillers and fibers. Then, if this magnetically susceptible and electrically conductive material is heated with electromagnetism. Heat is generated through the energy lost and finally the material melts and the crack is closed.

Microwave technology makes this new asphalt economically viable because of the following reasons:
*The steel wool content is around ten times less than that recommended for heating by electro- magnetic induction, which in practice could mean an important reduction in costs.
*The amount of electricity used by microwave devices is much less than that required to produce a similar effect by electromagnetic induction.

You can find extra information in this paper:
Heating asphalt mixtures with microwaves to promote self-healing (