Functional sustainability of single- and double-layer porous asphalt pavements

Abstract

Porous asphalt pavements have been used successfully in practice to improve stormwater management, increase wet-weather driving safety and reduce traffic noise. However, the sustainability of these functional performances is a major practical concern because they are often seriously affected by clogging during service. This paper proposes a laboratory evaluation procedure to compare the clogging potential of two common forms of porous pavement design, and how their drainage capacity, skid resistance and sound absorption properties are affected by clogging. For illustration, the following four designs were considered: (A) Single-layer design with 25% porosity; (B) Single-layer design with 20% porosity; (C) Double-layer design having on top of Design A a 20% porosity upper layer with 11.2 mm top size aggregate; and (D) Double-layer design having on top of Design A a 20% porosity upper layer with 8.0 mm top size aggregate. Test results show that Design A was least prone to clogging, followed by Designs B and C, and Design D was most prone to clogging. However, Designs A and B suffered severe losses in their sound absorption capability when fully clogged, while the other two designs were significantly less affected by clogging. These different behaviors of the porous asphalt designs with respect to clogging potential and sound absorption capability have important implications on pavement drainage capacity, skid resistance and noise management, and the frequency and method of declogging maintenance. They provide useful information for pavement engineers in the selection of porous asphalt surface course design.