Subgrade Integrity - Pervious Paving

[Scott367]

We are considering using pervious concrete on some of our upcomming projects. This is still untested stuff so I am probably being a little too conservative. I am in Ohio we get about 40 inches of rain per year and mostly clay based soils. Whenever I have a wet subgrade it performs very poorly. How am I too permit water to pass into my subgrade without degrading it? My first thought is to design the sugrade to drain to a network of underdrains. This option adds significant cost over conventional. Anyone have any experiance with this stuff? Do I need to take steps to keep the subgrade from going to mush?

 

[civilperson]

The benefits of pervious pavement is better traction in rain,(less hydroplaning). High speed curves and exit ramps are good applications. The pervious aggregate base used as part of the structural pavement section typically sits on a sloping, (greater than 2% cross slope), impervious sub-base which drains the water to perforated pipes along the shoulders or median. These drains can either daylight to the ditch of be collected into culverts and storm water sewers.

 

[cvg]

I would discuss this with your geotech before specifying it where you have clay subgrade. You will be introducing more water into your subgrade which is almost never a good thing to do. Higher cross slopes and grooved pavement are also good ways to reduce hydroplaning and might be cheaper.

 

[Scott367]

The application I am considering is car parking lot. My slopes will be between 1% and 2%.