ASSESSMENT THE POLISHING OF LOCAL AGGREGATES BY MEANS OF SKID RESISTANCE FOR SURFACE PAVEMENT LAYER

Abstract

During the entire life cycle of a pavement, highway agencies are expected to monitor and preserve an appropriate surface roughness (i.e. texture) to facilitate friction between pavement surface and vehicle tires. The resistance of pavement surface to sliding and skidding of the traveling vehicles is measured by skid resistance. There is of prime importance to provide skid resistance to preserve adequate surface roughness for pavement and prove resistance to polishing due to the traffic effects. The skidding resistance of asphalt pavement essentially depends on aggregate properties in the surface wearing course. Depending on the shape, size, and gradation of aggregate in the paving mixture of the wearing surface, the skid resistance performance of the road surface varies differently with environmental and traffic operating conditions. Field experience in Iraq has indicated that wearing surfaces with different aggregates differed in their skid resistance at different stages of their service life. This research reports the findings of an experimental study for investigating the effects of aggregate properties on skidding resistance for three common types of local aggregates used in Baghdad for road construction, they are brought from Al-Nebae quarry in Salahdin governorate, Al-Sedoor quarry in Diala governorate and Chlatt quarry in Misan governorate. However, this study was designed to characterize the polishing properties of the three types of aggregates in an attempt to explain their different skid resistance performance...