Falling head and constant head methods are, respectively, used to measure the permeability of pervious concrete samples. The measured permeability is found to be decreasing with the applied pressure difference on the sample but does not obey the Klinkenberg effect. The permeability is found to be increasing linearly with the reciprocal water pressure, similar to the Klinkenberg effect.
The permeability measured by the CHM is lower than that by the FHM. The selection of the starting and finishing water heads from the FHM strongly affects the calculated permeability. The difference decreases as the water head approaches zero. Due to this correlation, the water permeability of permeable concrete should be reported with the applied pressure and the associated testing method.