Can pervious concrete handle traffic loads greater than a parking lot?
Pervious concretes can develop compressive strengths in the range of 500 to 4000 psi, which can handle most traffic except for heavy truck traffic. The flexural strength ranges between 150 and 550 psi.

Is the freeze-thaw cycle a problem?
Pervious concrete has been placed in freeze-thaw climates for more than 15 years. It is inherently resistant to freeze-thaw damage since water is not retained in the structure. For wet freeze climates like those in the Midwest, it is recommended that the cement be air-entrained and that the pervious concrete be placed on 6-12 inches of drainable aggregate base. Pervious concrete is also gaining recognition for its snow-handling characteristics. As snow melts on pervious concrete, helped somewhat by the circulating air in its voids, the melt immediately passes through the pavement. This reduces the safety concerns associated with slipping and sliding, and filters salts and de-icers that would normally run off to sewers.

What about clogging?
Clogging is not a big issue. If the site allows stormwater from outside of the parking lot to flow across and introduce fines onto the pavement, sweeping, blowing, or vacuuming will be enough to maintain the pavement. Also, with the rate of flow inherent in pervious concrete, even 90% clogging would still allow enough water to pass through to be effective for most rain events. Coring studies indicate that, on well-designed pervious concrete parking lots, less than 10% loss of internal volume has occurred due to infiltration of fines after 12 years.

Can pervious pavements be used over impervious, clayey soils?
Yes, but the pervious concrete should be installed over a permeable sub grade layer of rock several inches thick. This additional layer will allow the pavement to hold more water until it’s absorbed into the ground. Consult a geotechnical engineer for design and construction options specific to the soil in your area.

Isn’t pervious concrete is a lot more expensive than regular concrete?
Pervious concrete may cost up to 25% more to install than conventional concrete, but when lifecycle costs and the savings associated with reduced stormwater management
infrastructure are considered, pervious is much cheaper. It important to consider the cost savings attained when use of pervious concrete negates the need for constructing expensive off site stormwater retention (and devoting valuable real estate to do so). Further, when we consider the non-market values associated with using an unstable petroleum based product such as asphalt vs. a stable product such as pervious concrete that promotes pollutant removal, we find that the ecological cost of pervious is much lower.