Permeability of Porous Friction Course Pavements

This study investigates the effect of permanent deformation on the permeability of different asphalt porous friction course (PFC) pavements with heavy vehicle simulator (HVS) testing. The testing was performed under controlled temperatures, speeds, and loads. HVS rutting tests were performed with single and dual wheels. Under dual-wheel loading, dust was added to one of the tire tracks to determine the impact of aerially deposited dust on surface clogging of permeable pavements. Permeability measurements were performed to evaluate clogging related to dust and permanent deformation. Measurements were made on each test section before and after HVS operation with both ASTM C1701 and the National Center for Asphalt Technology (NCAT) methods. Results obtained from this study showed that (a) permeability measured by ASTM and NCAT methods were correlated, especially when a smaller ASTM ring was used, but generally the values measured by the ASTM method were larger than those by the NCAT method; (b) sections with thinner PFC layers were more prone to clogging, with after-HVS permeabilities close to zero; (c) the majority of reduction in permeability values (40% to 60%) occurred after about 2,000 repetitions (less than 6-mm downward rut depth) and in most cases the permeability was reduced to near zero after 5,000 to 30,000 repetitions; and (d) the addition of dust particles (<38 μm) did not significantly change the permeability of PFC layers; this finding indicated that the loss of permeability was primarily because of permanent deformation accumulated during the HVS operation. For this reason, the rutting performance of PFC pavements should be considered to assess the long-term effectiveness of permeable pavements for stormwater runoff control and management.