Development of a Hollow Cylinder Apparatus to investigate the shearing characteristics of asphalt

This experimental project will address the problem of wheel track rutting that develops in asphalt road pavements under repeated traffic loading. A new torsional Hollow Cylinder Apparatus will be developed to reproduce, more accurately than hitherto, the field loading regime in the laboratory, so that high quality measurements can be made of the permanent strain that accumates under cyclic loading. Collaboration with the University of California at Berkeley and at Davis will allow use to be made of their established but less accurate asphalt shear testing equipment using identical material. Pilot scale wheel tracking tests will be conducted in the Nottingham Pavement Test Facility to generate rutting performance data and use will be made of full scale test data from the Californian team. The outcome of the project is aimed at improving prediction methods for rut development in asphalt pavements and to assess the reliabilty of a simple practical test for use by industry to estimate the rut resistance of asphalts.