Performance of permeable pavements under low volume traffic loads in Calgary
Creators: name: Modeste, Kerwin
Publisher: name: University of Calgary
Year: 2012

description: Bibliography: p. 197-209
description: Many pages are in colour.
description: Permeable pavements (PPs) have been used as a means of managing runoff and for associated environmentally friendly applications. Most of the research on PPs focused on the hydrological performance and was done primarily in mild climates, with little information available for cold climates. Hence, the City of Calgary commissioned this research on the Performance of Permeable Pavements Under Low Volume Traffic Loads in Calgary (The PPP Research) to better understand the perfonnance of permeable pavements under low volume traffic loading in Calgary. It is intended that the findings of the PPP Research will facilitate the development of a City of Calgary specification for the use of permeable pavements. A site located at the Currrie Barracks in the S.W of Calgary was the designated site for the PPP Research. The site was divided into three individual cells (cell No. I to 3) with PCP, PICP, and PACP as the wearing course respectively. It was assumed that the three cells would perform similarly under low volume traffic loading; and the freeze and thaw cycles of Calgary's climate. Each cell was isolated through the use of an impervious HDPE liner. The structure of cell No. I consisted of a reservoir course with PCP as the wearing course. Cell No.2 consisted of a reservoir course overlain by an intermediate course. The intermediate course was overlain by a choker course. The choker course was overlain by a bedding layer with PICP as the wearing course. Cell No.3 consisted of a reservoir course overlain by a choker course with PACP as the wearing course. A pressure cell was placed on the subgrade in each cell; and two strain gages were placed immediately below the wearing course in each cell ( one in the transverse direction, and the other in the longitudinal direction) to monitor the stress and strain response to traffic loads. A network of 100 mm perforated PVC sub­drains equipped with shutoff valves were placed in each cell to manage the flow of infiltrating runoff and groundwater. The sub-drains were connected to a monitoring catch basin. Temperature loggers were placed at various locations within the pavement structure in each cell to monitor the temperature gradient across each cell. A tandem axle truck loaded with gravel was driven in the east bound lane (the test lane) in order to determine the stress and strain response within each pavement structure. Prior to the stress and strain response testing, the load distributed to each axle; and the pressure in each tire was measured. The centerline of each pavement structure and the locations of the pressure cells and strain gages were marked with paint to ensure that the truck was driven in the test lane, and the wheel paths were directly over the pressure cells and strain gages, respectively. The data acquisition was achieved using a data acquisition system equipped with lab-view. The surface deformation of each pavement structure was measured with a laser level subsequent to each stress and strain testing. The stress and strain testing was carried out in September, October and December of 2011. The impact of the freeze and thaw cycles was assessed between December 2011 and February 2012 to evaluate the extent of frost heave in each pavement structure. The findings of the PPP Research indicated that the PCP showed the best structural performance with the exception of some ravelling. The PCP showed the least deformation and the impact of frost heave was lowest in the PCP.