Influence of Aggregate Gradation on Clogging Characteristics of Porous Asphalt Mixtures

This research investigates the influence of aggregate gradation on the clogging characteristics of porous asphalt mixtures. Ten representative gradations used for open graded friction course (OGFC) applications from across the United States were used in this evaluation. The aggregate gradation was found to be strongly correlated to the macrotexture depth of the porous pavement and the permeability of the mixes both before and after clogging. Utilizing graded sand as the clogging material, it was also found that the operational (or secondary) clogging rate is approximately half of the measured initial clogging rate. Additionally, the operational clogging rate can be estimated from the R15 value for the system, which is the ratio of the D15 of the porous asphalt gradation to the D15 of the clogging material.