The self-healing aspect of the asphalt is very interesting, but the big problem with porous asphalts (there's a lot of research in the area performed by Purdue, US DOT/Volpe Center and other places) is that road salt and dirt tends to clog up the pores over time, reducing the drainage and noise-reduction properties of the material. I was disappointed that the presentation didn't address this.
Also, in northern climates, the water will get in the pores then freeze and expand. It may be self healing, but in a matter of weeks the road would be still be completely rubbish
Concrete is also a common paving material, even in situations for which drainage and noise-reduction would be important, and it is far less porous than any asphalt. Perhaps highway engineers simply have other methods for achieving these two goals, and don't find it convenient to rely on porosity?
Perhaps highway engineers simply have other methods for achieving these two goals, and don't find it convenient to rely on porosity
In terms of noise reduction, there are other things you can do to the roadway (basically different forms of grinding/milling the surface to create different rolling textures) to reduce noise, but these methods a) only provide minor (a couple dB) reduction in noise and b) can negatively affect surface friction which increases longer stopping distances, etc. Concrete (by which I mean portland-cement concrete) is also problematic in northern climates, which is why you don't see it used extensively in northern states. I'm not a water quality/watershed expert so I won't speak to that.
One solution I have seen to address clogged pores is to use vacuum trucks to suck up the grit, but I've seen enough presentations by highway engineers to know that this is not considered to be a viable long-term solution.
As the video showed, the healing process does require the external provision of heat. It doesn't self-heal just by sitting there as some other materials claim (eg walls that "eat" pollution).
