Pervious concrete includes aggregates that are gap graded as opposed to well graded. That is, some of its aggregate sizes are ommitted to insure 20 percent voids.
The voids are interconnected and allow surface water to enter the base material quickly. Bases used under pervious concrete are designed to hold surface water so that it can naturally seep into the subgrade below.
We have several pervious concrete and porous asphalt test sections at our research facility where we are trying to understand their applicability in a cold weather region.