(How?)Blender GLSL node - Wet asphalt

Hi!
Can anyone help me how setup node for wet asphalt like this:

[video]www.youtube.com/watch?v=HxXqHNKFJwg[/video]

or:

[video]www.youtube.com/watch?v=kBT4w4eggnY[/video]

If you are not busy, please attack a .blend sample…, please. I search 4 months for this but didn’t find anythong:(