Hydraulic Design of Permeable Interlocking Concrete Pavement—Design Tool Development

Abstract

The concept of storm water management to improve quality and control quantity has recently become of greater importance due to new improvements to and technologies from compliance with the Phase II of the National Pollutant Discharge Elimination System (NPDES) Permit Program of the Clean Water Act (CWA). Best management practices have been implemented in urban landscape as flood and drainage controls because an increase in urbanization caused a major increase in the amount of impervious area. Impervious surfaces, such as pavement, currently produce 25% of the impervious area in urban environments, and the runoff carries large amounts of heavy metals and hydrocarbons. Permeable Interlocking Concrete Pavement (PICP) is a type of best management practice that uses filtration, infiltration, and detention to improve the amount of impervious surface runoff while creating a surface that can be applied for both vehicular and foot traffic. This paper addresses the gaps in the current design process of PICP. If installed properly PICP can be an extremely beneficial, but the design process is still rather unrefined. The purpose of this paper is to use data collected from a typical PICP cross section in a laboratory flume. The PICP were tested with variations in block spacing (6mm, 10mm, and 12.5mm) and slope of the flume (0%, 1%, 2%, 5%, and 10%). Using the results, it was possible to determine the flow rate necessary at each slope and block spacing for by-pass across the PICP section. This calculated flow rate was used to determine the horizontal infiltration across the PICP. Using both the knowledge of the horizontal and vertical infiltration of the PICP, a design tool was created to utilize the site qualities, such as typical storm data and pervious to impervious area, in order to determine the most appropriate design infiltration for the site to maximize decrease in runoff. This paper is beneficial for establishing permeable pavement performance and giving further design recommendations.