SPR 15-493: Development of a Laboratory Test for Evaluation Of Geogrid Materials

This research will evaluate alternative laboratory tests to determine material properties of geogrid that impact in-situ performance of geogrid used for subgrade stabilization. This will allow the Cabinet to objectively evaluate various geogrid materials that are submitted for approval. Further analysis will be conducted to illustrate cost savings by optimizing geogrid position within the structure. Highway construction routinely uses geogrids for subgrade stabilization. This construction practice involves placing an appropriately specified geogrid on a weak subgrade prior to placement of roadway subbase. The geogrid provides stabilization of the subgrade by increasing the load-carrying capacity of the system. Subgrade stabilization allows for a firm construction platform to be built with less aggregate and less construction time as compared to construction without the stabilization geogrid. There is a general consensus concerning the effectiveness of geogrid in this application; however, there is a lack of understanding and agreement on the material properties needed for performance. There are many new geogrid manufacturers coming onto the market many of these have developed their own methods for comparison and evaluation between different types and strengths of materials. This study will examine the field performance of various geogrids for subgrade stabilization with the aim of relating this performance to material properties tested in the laboratory that can be incorporated into standard specifications. This study will also develop a method to evaluate the potential structural benefit provided by different geogrids. In addition, it would assist in the development of final use guidelines for pavement construction.