Comparison of Surface and Subsurface Winter Temperatures in Pervious and Conventional Concrete Pavements

Abstract

The purpose of this research was to compare the surface and subsurface winter temperatures in pervious and conventional concrete pavements placed in June 2011 at the Headwaters Resources Pervious Concrete Demonstration Project in northern Utah. Thermocouples were installed at the site to facilitate monitoring of the air, surface, and subsurface temperatures on hourly intervals from January through December 2012. The collected temperature data were separated into six time periods defined based on sunrise and sunset times occurring in each month so that the effects of solar radiation would be consistently accounted for in each period. For each of the six time periods, pervious and conventional surface and subsurface temperatures were plotted against air temperature, as measured by the thermocouples, and then linear regression was used to determine from each plot the air temperature associated with a pavement temperature of 0°C at the instrumented surface or subsurface location; this approach allowed fair comparisons of the two pavement types even when the air temperatures were not identical at every time interval. The results indicate that, for materials and conditions similar to those investigated in this experiment, pervious concrete may be expected to provide greater protection against surface freezing during late morning and early afternoon than conventional concrete of the same thickness. During the warming trends typical of these time periods, the pervious concrete reached 0°C more quickly than the conventional concrete; however, for the other time periods, during which cooling trends may have been more typical, the data suggest that the surface freezing characteristics of the two pavement types were similar. Regarding subsurface freezing, pervious pavements are expected to provide greater resistance to freezing than conventional pavements across all time periods, attributable to the greater latent heat within the former compared to the latter.