What is Porous Asphalt?
Definition of Porous Asphalt in Construction
A new product designed to allow water to move through the asphalt layer. Porous asphalt is used in areas that require drainage, without the ability to provide the proper layout and piping of a storm water system.
In addition, porous asphalt allows the water to penetrate the asphalt surface and eliminates the run off inherent to large parking areas or expanses of asphalt paving. Porous asphalt must be maintained by removing the silt and sand from the pores of the asphalt. The removal of the material is either vacuumed up with large industrial vacs or forced down into the sub base by power washing the surface. Porous asphalt is many times used in conjunction with standard storm piping and catch basins. If an area of the pavement is going to accept a continuous sheet flow of water and there is not an easy way or architecturally sensible way to pitch the pavement towards the catch basin, the use of a portion of porous asphalt maybe required. In most cases, the sub base of the porous asphalt must be a product that will easily distribute the storm water, once it percolates through the porous asphalt. In most cases, this is a stone base wrapped in a filter fabric. The design of the porous asphalt must be designed as a system with the sub base providing ample ability to dissipate the water.