The design of porous asphalt mixtures to performance-related criteria. Prepared for Highways Agency, Pavement Engineering Group, Quality Services (Civil Engineering).

Four laboratory tests, permeability (both vertical and horizontal), particle loss, scuffing and affinity between binder and aggregate, were used to assess porous asphalt samples taken from site with those manufactured in the laboratory. The results indicate that the potential of a mixture to achieve requirements for hydraulic conductivity on site can be assessed from laboratory mixtures, but there was insufficient variation between the samples in the laboratory tests to be able to predict the durability of the material in service. A laboratory design procedure for porous asphalt is proposed which should assist in reducing the current high cost of the material when procured under the current specification clause or, in future, under a performance-related clause. Also, supporting advice on binder selection, aggregate selection, fillers and adhesion agents, aggregate grading, durability and permeability is included. (Author/publisher).