Drainage capacity of pervious pavement mixtures is commonly measured using a falling head permeameter at hydraulic heads much higher than expected in the field. Recent advancements in computational fluid dynamics (CFD)- and X-ray computed tomography (XRCT)-based modeling eliminates the laboratory challenges of maintaining lower hydraulic heads. However, improper characterization in digital image processing (DIP) and finite-volume simulations resulted in significant errors in permeability measurements and fluid flow behavior. In addition, past studies have identified non-Darcy fluid flow characteristics in pervious pavement mixtures following the Izbash and Forchheimer laws. This paper attempts to bridge this research gap by comparing the Darcy and non-Darcy permeability parameters at different laboratory and field hydraulic heads using advanced XRCT-based modeling. It was found from the analyses that the use of laboratory hydraulic head could result in significant underestimation of permeability parameters compared with the field hydraulic heads for Darcy and Izbash equations (by up to 73%), and overestimation for Forchheimer equations (by up to 216%). Fluid flow behavior in pervious mixtures was found to be in transition flow regime (neither laminar nor turbulent) at both laboratory and field hydraulic gradients. Overall, this study can help in a better fundamental understanding of the current limitations of laboratory measurements and the need for XRCT-based numerical modeling to bridge field and laboratory permeabilities of pervious pavement mixtures.

Grooving of pavement surface and tire tread has been accepted as good practice to enhance road travel safety against wet weather skidding and hydroplaning. Many guidelines on this practice have been derived from findings of experimental studies and field experience. However, theoretical studies to provide insights into the factors and mechanisms involved are lacking. A theoretically derived analytical simulation model was used to study the relative effectiveness of pavement grooving and tire grooving in reducing vehicle hydroplaning risk. Three basic grooving configurations were considered: ungrooved, longitudinally grooved, and transversely grooved. There are nine different combinations of grooving configurations. To form a common basis for comparison, constant values of groove width, groove spacing, and water-film thickness were considered in the computation of hydroplaning speeds for different groove depths. Transverse grooves performed better than longitudinal grooves in raising hydroplaning speed (i.e., reducing hydroplaning risk), and pavement grooving was a more effective measure than tire tread grooving in reducing hydroplaning risk. Further detailed examinations of the results were conducted to study the practical implications of the findings. For longitudinal grooving, which is commonly adopted in highways, pavement and tire grooving are of equal importance in their contributions toward reducing hydroplaning risk. In the case of runways where transverse grooving is the standard practice, pavement grooving is the dominating component in guarding against hydroplaning.