Pervious Concrete

Pervious Concrete Pavement: A Win-Win System, Concrete Technology Today, August 2003, a three times a year newsletter from the Portland Cement Association, discusses concrete pavements with high porosity. Also known as no-fines concrete or porous concrete, this 50-year old technology is gaining renewed attention for its ability to contribute to improved storm water management.

Unlike conventional concrete mixes, the aggregate in pervious concrete is narrowly graded. By omitting smaller sized aggregates, and limiting the amount of cement paste, interconnected voids may constitute 15% to 35% of the final concrete after curing. The interconnected void spaces allow water to pass through the concrete and percolate into the ground below. According to the article, percolation rates of pervious concrete may range from 2 to 18 gallons per minute per square foot of surface. The large percentage of void space also makes pervious concrete lighter and less strong than conventionally formulated concrete. Its compressive strength may range from 500 psi to 4000 psi, and its density may vary from 100 to 120 pounds per cubic foot.

This article provides more information about mix design for pervious concrete, its application to various site pavement applications, and its benefits related to federal clean water regulations.