Subgrade Temperature and Freezing Cycles in Pervious Pavements

Abstract

With the construction of four new test cells in 2008, the Minnesota Department of Transportation (Mn/DOT) now has six unique pervious pavement test sections at the MnROAD test facility. Recorded temperatures in the pervious pavements and subgrades were compared to impervious Portland Cement Concrete (PCC) test sections over the same time interval. It was found that the subgrade in pervious PCC and Hot Mix Asphalt (HMA) was up to 4 °C warmer in the winter than impervious PCC pavements. The frost depth in an impervious PCC pavement was found to be 45.7 cm deeper than in a pervious PCC pavement of similar thickness. One pervious pavement test cell experienced 60% less freezing cycles over a three year interval than impervious PCC pavements of similar thickness. The air trapped in the pavement voids was suspected to be the main reason for the reduced number of freeze-thaw cycles by creating an insulating effect. In another pervious pavement, entrapped air within the base material may also insulate the pavement from the subgrade.