The Role of the Binder in the Maintenance of Resistance to Skidding of Dense Asphaltic Surfacings under Heavy Traffic

摘要

Three full-scale experiments show that, under heavy traffic, the type of binder has an important effect on the level of S.F.C.50 attained by rolled asphalt; a similar effect was found for asphaltic concrete. Binders that weathered most provided surfacings having a value for S.F.C.50, 0.10 higher than that provided by binders which weathered least. The binder acts by promoting a gradual wear of the sand/filler/binder mortar of a rolled asphalt; the wear is brought about by weather and traffic and exposes unpolished aggregate and maintains a rough microtexture of the mortar itself. In one experiment the asphalts which wore to give the greatest depth of texture also gave the highest values for S.F.C.50. Another experiment showed that the weathering properties of the binder have less effect when a very heavy application of chippings is used; a high depth of texture of 1.25mm has been obtained under heavy traffic for binders having intermediate to high weathering characteristics. The ranking of the binders provided by the experiments is being used to assess the value of laboratory tests to predict this aspect of performance. Recommendations have been made for improving the resistance to skidding of rolled asphalt. (Author)