Porous Concrete is made with little or no sand and generally uses larger pea gravel, so the look is not as smooth as conventional concrete. It is available through most concrete suppliers.
To help reduce surface runoff, consider using permeable pavers — porous pavement — instead of old-fashioned concrete. Originally published as
Porous Pavements by Presto Geosystems GreenBuild 2010
A marker embedded in the pavement marks the imaginary line between the United States and Mexico at the San Ysidro border crossing between San Diego, Calif., and Tijuana, Mexico.