Use of Porous Bases for the Drainage of Concrete Pavements in the USA

In the United States, many States are using free draining porous bases under new portland cement concrete pavements. These porous bases are intended to remove infiltrated surface water, which cannot be prevented from entering the pavement structure. The porous bases used in the United States have coefficients of permeability ranging from 4 to 50 mm/second. A typical thickness for the base is 100 mm. Unstabilized porous bases are constructed using 100 percent crushed stone to provide stable slab support through aggregate interlock. Stabilized bases use 2 to 3 percent by weight asphalt or 90 to 150 kg of portland cement per cubic meter.