Resistance to Permanent Deformation of Road and Airport High Performance Asphalt Concrete Base Courses

The paper discusses the results of a laboratory investigation aimed at analyzing the rutting susceptibility of high performance asphalt concretes, made with three different bituminous binders and four types of artificial and recycled aggregates (steel slags, glass wastes, municipal solid waste incineration bottom ash and coal ash), used in partial substitution of the natural limestone. The experimental study has been focused on the characterization of the physical-mechanical properties of the marginal materials, as well as on the volumetric mix design and the permanent deformation evaluation (by means of Creep Recovery Tests, Repeated Load Axial Tests, Wheel Tracking Tests) of bituminous mixtures for road and airport asphalt concrete base courses. Because the requisites for acceptance in the Italian Specifications and Standards have been satisfied and given the positive mechanical performance (indirect tensile strength at 25°C on dry and wet samples up to 1.27 MPa and 1.07 MPa respectively), it has been verified that the marginal aggregates investigated can be used as substitution of the lithic materials in the base courses, also with very high content (up to 70% on the weight of the aggregates).