Long term behavior of geotextiles as filters in drainage structures is often a concern of many users. In order to analyse this and other drainage issues, Highway Department os State of Parana has carried out a comprising practical research program, in which they included the construction and monitoring of six test sections of drains with different filters (granular materials and geotextiles). After four years, the sections were openned, and lab analysis were made i .the collected materials.
The good performance of sections with nonwoven geotextiles was remarked, which led to the conclusion that, for the local conditions, their durability will be much higher than the pavement lifetime.