Long term filter intrusion phenomenon in several types of drainage structures

Short term intrusion phenomenon of fleeces in the drainage cores is taken into account in the product performances by using the appropriate contact surfaces Rigid/Foam or Foam/Foam in the in plane water flow capacity test (EN ISO 12958). The consequences of both these options on the hydraulic performances of the drainage products depend on the normal stress, the type of the drainage core, the space between fleece/core contact areas, the properties of the fleece, and whether the fleece is added on site or in a factory. This paper is based on testing program designed to follow the intrusion phenomenon on the long term under a normal stress of 100 kPa. Several drainage composites with various drainage core structures are tested.