Moderator: Richard Thiel, P.E., Thiel Engineering
Geocomposite drainage layers are ingenious materials that have been developed by manufacturers for use in civil projects. Heat lamination of the geotextiles to the geonet cores is subject to the art of manufacturing. The method of testing and specifying the quality of this lamination has evolved over time. Very little effort has gone into a detailed engineering evaluation of the durability of this interface for long term shear strength. Meanwhile, there has been, and continues to be, a large and heretofore unrecognized variability in the level of bonding created at this interface that has recently been realized. Preliminary conclusions are that the current industry standard for testing only 5 specimens across the roll width this for the lamination strength is inadequate. Proposals are needed for the type and extent of index testing that is required to adequately take into account the high level of manufacturing variability. Proposals are also needed to evaluate the long-term durability of a given level of lamination to provide reliable shear strength. Designers would then be able to take the outcome of the answers to these two requests for proposals to develop project specifications.