Slip-related characterization of gait kinetics: Investigation of pervious concrete as a slip-resistant walking surface

Slip-related falls are a significant health problem, particularly on icy walking surfaces. Pervious concrete, a material allowing rapid exfiltration of melted ice from the walking surface, may help reduce slipping risk. Therefore, the purpose of this study was to compare slipping characteristics of traditional and pervious concrete walking surfaces in icy conditions using kinetic biomechanical analyses. We hypothesized that pervious concrete, in comparison to traditional concrete, would be characterized by less severe ice-related alteration of friction during gait. Healthy young participants performed gait trials on traditional and pervious concrete surfaces during dry and icy conditions. Ground reaction forces were used to determine maximal magnitude and timing of loading phase normal force, shear force, and normalized friction usage, defined as the ratio of shear to normal force normalized to static coefficient of friction. Pervious concrete, in comparison to traditional concrete, exhibited smaller ice-related increases in normalized friction usage. While ice-related delays in achieving peak friction were observed on traditional concrete, icy conditions did not have an impact on maximal shear force magnitude or timing on pervious concrete. Our results indicate a larger margin between friction forces used during walking and those that would cause a slip, suggesting that pervious concrete may be a more slip-resistant alternative to traditional concrete in icy conditions. The findings reported here may lead to pavement design recommendations for the use of pervious concrete in areas of high pedestrian traffic and elevated slipping risk.