This paper outlines the effect of aggregate crushing on the skid resistance of chipseal road surfaces. Two sets of experimental work are described: British Pendulum measurements on samples that have been polished according to polished stone value (PSV) procedures and GripTester measurements. This experimental work, undertaken on laboratory-prepared chipseal surfaces, indicates that the skid resistance of new (i.e. unpolished) surfaces using aggregate with 100 per cent crushed faces is 20 per cent greater than surfaces constructed with uncrushed aggregate. The benefit of crushing on skid resistance is shown to be greater for new and unpolished chipseal surfaces than for terminally-polished surfaces. This is thought to be a result of the effect of polishing in reducing the microtexture of crushed faces, and smoothing sharp chip edges that are initially angular. The skid resistance values reported here are thought to be influenced by the low slip speeds of the skid testers compared to what would typically be experienced by skidding vehicles, particularly for the GripTester which was used in push mode (0.75 km/h slip speed). (a) For the covering entry of this conference, please see ITRD abstract no. 0612AR242E.
Samenvatting