1. A composite drainage network is normally laid between the foundation and the subsoil, mainly to reduce water accumulation. This method not only shortens the drainage time but also reduces the use of selected foundation materials and greatly increases the service life of the road.
2. The laying of composite drainage network at the subbase layer can prevent the subbase fine material from entering the subbase layer (that is, to play the role of isolation). The aggregate base enters the upper portion of the geogrid to a limited extent. Thus, the composite geogrid also has a potential effect of limiting the lateral movement of the aggregate base, which in this way is similar to the strengthening effect of the geogrid. Generally speaking, the tensile strength and rigidity of composite geotechnical drainage network are better than that of many geotechnical grids used for foundation reinforcement.
3. Road aging, crack formation, most of the rain will enter the section. In this case, the composite drainage network is laid directly under the road surface in place of the drainable foundation. The composite drainage network can collect moisture before it enters the foundation/Subbase. A film can also be placed on the bottom end of the composite drainage network to further prevent moisture from entering the foundation. For rigid road systems, this structure allows for the design of roads with a high drainage coefficient Cd. Another advantage of the structure is that it may allow the concrete to hydrate more evenly (research on the extent of this advantage is underway). Whether for rigid or flexible road systems, this structure can extend the service life of roads.