2023 Volume 78 Issue 2 Pages I_248-I_255
This study proposes new pavement structure for roadway rainwater runoff control which is expected to be alternative to permeable pavements. The proposed structure collects surface rainwater to roadside ditch and leads it laterally to granular subbase course through inlets on the wall of the ditch. One expected advantage of this structure is that it allows inflow only during peak-time of rare big floods such as several-year-return period. It may solve the problems on mechanical durability, flood control efficiency, maintenance and groundwater and soil environment that are major concerns in permeable pavements. The authors conducted hydraulic model experiments to investigate basic lateral inflow characteristics to granular subbase course. Number of inlet holes on the ditch wall and their locations were varied in the experiment. The results showed that regardless of the number of inlets, the amount of inflow into the roadbed affects the water table difference. It was also found that grain size of subbase course material affects horizontal permeability because it changes the pore system, but does not significantly affect the ability of the roadbed to store water because the porosity itself does not change.