Cleaning Pervious Pavement
Mr. Nixon is correct. I generally design the parking lot with 12" thick layer of crushed stone (2"-3" dia), then 6" of #57's, 2" of washed #8's, and then the brick pavers. Aqui-bric and a few others have ribs along the sides to make sur there is enough gap for water to flow in. Finally, sweep #8's in the joints to tie it all together.
The base stone gives you plenty of stormwater storage capacity. I noticed last winter the snow melts off the pavers faster than asphalt pavement. I guess with the spacing heat is able to transfer up from the ground.
Gary
It seems louder to me unless that's not open grade asphalt.
Smooth asphalt is very quiet but most of the asphalt surfaced freeways around here have a rough gravely surface which roars inside the car. I might have thought those rough surfaced roadways are open grade when they actually are not although they don't have the sheen of water on them in the winter storms like open graded asphalt.
The purpose is to increase skid resistance (e.g. better traction) by reducing hydroplaning so it is true they reduce water on the surface.
I'm surprised they claim it is quieter unless those surfaces are not actually open grade.
There is a section of I-80 east of Davis (I assume west of the causeway) which is supposed to be open graded asphalt pavement specifically put down in the late 90s by Caltrans for noise testing.
I don't remember that specifically but I will notice it next time I am over there (which is fairly often).
http://www.dot.ca.gov/hq/env/noise/pub/CaliforniaTestsShow.pdf
But on I-80 east of Roseville they have some super noisy pavement. It might be a densely graded asphalt pavement with large angular aggregates.
Yep,
I recently reviewed the 2005 Illingworth & Rodkin 7-yr report on the OGAC on I-80 near Davis.
It provides data on both the near and long-term benefits OGAC has for noise attenuation. As I recall this section of road was still getting over 4 dB of attenuation over baseline after 7 years due to the OGAC placement.