Vertical Porosity Distributions in Pervious Concrete Pavement

Pervious concrete is an alternative paving material that may alleviate many of the environmental problems caused by urban runoff from developed areas. Additional research is important so that pervious concrete can be better specified and more effectively used. An important property of pervious concrete is porosity, which will affect the hydrological and strength properties of the material. This research shows that there is a vertical distribution of porosity in slabs placed with certain placement techniques. The vertical variation of porosity can affect the strength distributions within the material and the permeability of the system and its potential for clogging. These studies indicate that for slabs approximately 15 cm (6 in.) in height and placed with an approximately 10% surface compaction technique, the porosity increases significantly from top to bottom. A series of vertical porosity distribution equations have been developed to effectively model this using the percent compaction and average cored porosities.