resistance to polishing is the most important single characteristic of an aggregate in determining the resistance to skidding of a bituminous road surfacing. this report describes a study that has been made of other characteristics of aggregates that have been thought to influence resistance to skidding. the more important findings were:- 1. on average, quartzites and blast-furnace slags give a resistance to skidding equivalent to that given by other roadstones which are three units higher in polished-stone value. none of the other roadstone types studied (basalts, granites, porphyries and gritstones) showed an important departure from the average. 2. provided that adequate road surface texture is maintained, reducing the nominal maximum size of an aggregate raises the resistance to skidding of a surfacing made with it. 3. there is some indication that the use of more nearly single-sized chippings in surface dressings gives a better surface texture. 4. inadequate durability in an aggregate can affect the resistance to skidding of a road made with it. 5. mixtures of two or more roadstones in a road surfacing yield a resistance to skidding and a depth of surface texture that are approximately equal to the means of those given by the constituents on their own. (a).

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