Location and depth of pervious concrete clogging material before and after void maintenance with common municipal utility vehicles

In practice, it has been observed that the method of pervious concrete void maintenance depends on which machines or vehicles the owners have available. This research compares the abilities of three common municipal utility vehicles-a vacuum truck with a flexible, 200-mm (8-in.) hose; a vacuum street sweeper; and a regenerative air street sweeper-to remove clogging material from the voids of in-service pervious concrete pavements. By using optical microscopy, it was found that clogging materials rarely migrate into voids deeper than 12.7 mm (1/2 in.) from the surface. Furthermore, all three machines were able to remove clogging materials that were located within 3.18 mm (1/8 in.) of the surface. The clogging material that was located deeper than 3.18 mm (1/8 in.) remained within the voids but was likely disturbed by either the suction or the forced air of the maintenance vehicles.