Effect of Binder Types on Engineering Properties and Performance of Porous Asphalt Concrete

Porous asphalt concrete (PAC) has an open-graded aggregate mixture to yield high air voids; PAC is mainly applied to the surface drainage layer on high-speed trafficked highway pavements. The objective of the study was to investigate the effect of binder types on the engineering properties and field performance of PAC mixtures. Three binder types were selected for a 19-mm nominal maximum aggregate size gradation: conventional asphalt AR-80, polymer-modified asphalt, and high-viscosity asphalt. A series of laboratory tests were conducted to evaluate the engineering properties of the PAC mixture, including permeability, resistance to draindown, resistance to disintegration, resistance to rutting, and resistance to indirect traction. A 3-km in-service test road was constructed to monitor the performance of PAC pavements using these three binders. Polymer-modified binder was shown to minimize abrasion loss and enhance the durability of the PAC mixture. Test results indicated that the use of polymer-modified binder, instead of unmodified binder, reduced rutting and raveling. When the mixture contained high-viscosity binder, it showed the best performance in the field. Field measurements indicated improved drainage as a result of replacement of the conventional asphalt AR-80 binder with the polymer-modified and high-viscosity binders. PAC pavement surfaces provided good frictional characteristics once the asphalt binder film was worn from the aggregate.