The effects of geosynthetics on mitigation of rutting in flexible pavements

Abstract

One of the more important problems associated with asphalt concrete pavements is rutting. This phenomenon is mostly illustrated as a surface depression in the wheel paths due to load-induced conditions as well as improper mix design or insufficient compaction of hot-mix asphalt (HMA). Some of the latest techniques for mitigating the severity and/or decreasing of permanent deformations on asphalt concrete pavements, in other words, preventing the occurrences of wheel path ruts include incorporating geosynthetic products into pavement structure. The purpose of this thesis is to study the benefits of applying geosynthetic reinforcement for rutting mitigation in asphalt concrete pavements. Geosynthetics are referred to herein as geogrids, fabrics, or composites. The procedure suggests installing the geosynthetic material in an existing, in-service flexible pavement with an asphalt tack coat and then overlaying with a specified thickness of HMA. Rut depth measurements will be taken from a "Wheel Tracking" test using an available Hamburg Wheel Tracking Device (HWTD). The HWTD measures the combined effects of rutting and moisture damage by rolling a rubber coated wheel across the surface of an asphalt concrete specimen that is immersed in heated water. As a conclusion, Rutting is one of the main distress types to lead to pavement failure and is difficult to track and simulate with deformation/strain measurements in majority of materials of asphalt concrete. The purpose of this research study is to investigate the effectiveness of geosynthetics in mitigation of rutting in asphalt concrete pavements. Moreover, making a cost effective analysis of geosynthetic reinforced flexible or composite pavements with comparisons either included unreinforced pavements. The expected contribution of this study to the state of the art is to present a new laboratory study and its findings to help better understand rutting occurrence in asphalt concrete layer and its mitigation with the use of geosynthetic reinforcement. The aim of this work is to study the effects of applying geosynthetics as reinforcement in improving the rutting resistance of the asphalt pavement.