Cleaning Porous Pavements Using a Reverse Flush Process

Abstract

Porous pavements are asphalt or concrete pavement surfaces designed to allow moisture to flow through the surface into an underlying reservoir or into the subgrade soil. Porous pavements prevent pollutants from entering into the water table and therefore, are considered sustainable construction. However, porous pavements eventually fill with debris and get clogged, preventing water infiltration. Thus, the greatest barrier to the use of porous pavements is susceptibility to clogging. Therefore, a major maintenance objective for porous pavements is to prevent clogging of the void spaces within the pavement. This paper describes a potential process of removing particles trapped in the pores of the pavement by flushing water from the bottom to the top of the pavement. Four variables were evaluated in this laboratory experiment to determine effects on particle removal. These were: (1) water pressure; (2) clogging material; (3) pavement porosity; and (4) number of flushes. Results indicate the reverse flush process was effective on both types of clogging material evaluated, was independent of the pavement porosity, and worked for the lowest pressure tested.