Influence of Engineering Properties of Porous Asphalt Concrete on Long-Term Performance

Porous asphalt concrete (PAC) is a particular type of asphalt mixture that has a high content of air voids that is generated because of an open-graded design. The objective of the study is to investigate the effect of the engineering properties of PAC on field performance. Three binders were selected for evaluation: conventional asphalt, polymer-modified asphalt, and highly modified asphalt. Comprehensive laboratory tests, including permeability, resistance to draindown, resistance to disintegration, resistance to rutting, and resistance to indirect traction, were conducted to evaluate the engineering properties of PAC mixtures. Stiff binders were shown to resist against particle loss and to enhance durability of PAC mixes through thick asphalt binder films. According to the laboratory results, a test road was constructed to monitor the performance of PAC pavements with aggregates having a nominal maximum size of 19mm. Surveys for pavement performance were conducted at scheduled intervals. Test results indicated that the use of polymer-modified binders in surface courses was technically superior to that of traditional asphalt. There were indications of drainage improvement by replacement of conventional asphalt with polymer-modified binders according to measurements in the field. Porous asphalt-wearing layers were shown to maintain drainability for more than 8 years in this study. The engineering properties of PAC mixes obtained from the laboratory corresponded well with pavement performance evaluated in the field.