Hydraulic conductivity and water level in the reservoir layer of porous pavement considering gradation of aggregate and compaction level

Abstract

The reservoir layer of porous pavement comprised of coarse aggregate provides a structure for temporarily retention of water inside the porous media and gradually discharging water into the underlying layers. The main objective of the present study is to evaluate the influence of appointed gradation of aggregate, morphological properties as well as compaction level on the permeability and water elevation in the reservoir course. For this purpose, large-scale permeability test is carried out on two types of aggregate including crushed stone and river aggregate by establishment of different compaction level of considered gradations. Then, the water level in the reservoir course is assessed by developed analytical models. As expected, the hydraulic conductivity and turbulence of water flow are higher for rounded aggregate with more uniform gradation and lower compaction. Evidently, the permeability of aggregate specimen and consequently the estimated water level of the reservoir course are substantially influenced by the established particle size distribution rather than the compaction level or aggregate morphology. Finally, provision of specimen comprised of broader range of crushed aggregate with high-level compaction leads to the increment of water level in the reservoir course and flow regime between fully turbulent and laminar as characterized by power law.