Hydraulic Performance Assessment of Pervious Concrete Pavements for Stormwater Management Credit

Portland cement pervious concrete’s ability to infiltrate water has encouraged its use for stormwater management. However, the material has suffered historically poor acceptance due to a lack of data related to long term infiltration rates and rainfall retention which leads to an undefined credit for stormwater management. Before stormwater management credit could be estimated, it was necessary to develop a testing device to gather information from existing pervious concrete parking lots currently in use. Eight parking lots were examined to determine the infiltration rates of the pervious concrete, as well as to assess the soil makeup beneath pavement. A total of 30 pavement cores were extracted and evaluated for infiltration rates. Three of the sites had a pervious concrete section that included a gravel reservoir. Infiltration rates were measured using the application of an embedded single-ring infiltrometer. A mass balance model to simulate the hydrologic and hydraulic function of pervious concrete sections was developed. The purpose of the model is to predict runoff and recharge volumes for different rainfall conditions and hydraulic properties of the concrete and the soil. The field derived hydraulic data were used to simulate infiltration volumes and rainfall excess given a year of rainfall as used in a mass balance operated within a spreadsheet. The results can be used for assessing stormwater management credit.