Design of Geogrid reinforcement and Drainage composite for flexible pavement: Present challenges in practical applications (Paper 793)
Majority of roads in India are constructed as flexible pavements, wherein, the bulk of distress is in the form of either cracking (fatigue) or rutting (permanent deformation). Two ways are available to improve the serviceability of the pavement. The first option by increasing the thickness of different pavement layers and other option is by enhancing the rigidity or quality of pavement layers by inserting polymeric materials like geosynthetics.
Inspite of numerous advantages of geosynthetics in pavements, these materials are facing several difficulties for implementing in field. Globally geosynthetics has been used in the construction of pavements for more than a decade, yet there exists no design guidelines in India to accept the technology. This has become a major challenge for the use of geosynthetics in pavement. Geogrid reinforcement is extensively used for stabilization of paved and unpaved road bases on soft soils. There are several methods to design geogrid flexible pavements like AASHTO method, Giroud–Han method, Leng–Gabr method, etc. The design methods presently available for use of geogrids in road base stabilization provide insufficient information about the required number of layers and the mechanical characteristics of geogrids so there are no specific guidelines explaining the methodology of geogrid reinforced flexible pavement and hence, implementing this technology practically has been a difficult task. For drainage composite, Design of drainage composite in base and subbase layers helps to reduce the thickness of layers and more adequate for drainage purposes rather than ordinary open graded base layer.
In this paper the design of flexile pavement by geogrid as reinforcement, design of drainage composite for draining of water from base and subbase courses and practical challenges associated with the use of geosynthetics is explained.