Geosynthetic stabilized flexible pavements: a critical appraisal for Indian scenario

The Guidelines of Indian Roads Congress IRC:SP: 59-2019 provide the design methodology for the use of geosynthetics in fexible pavements for the first time in India. The design methodology is based on a Mechanistic-Empirical (M-E) design method and the concept of Modulus Improvement Factor (MIF) for the reinforcement efect in granular layers. The design concepts of M-E design procedure and a brief history of the mechanical stabilization of fexible pavements have been presented in this article to beneft Indian pavement engineers. A parametric analysis has been conducted using the M-E design method for diferent subgrade strengths to quantify the efects of stabilization of granular layers in fexible pavements. The Base Course Reduction (BCR) values attained for geogrid and geocell stabilization of the granular layer is presented. It is observed that both geogrid and geocell stabilization have resulted in considerable BCR values for all the subgrade strengths but with higher reduction attained for low subgrade strengths and higher trafc. The reductions obtained for stabilization with geocell appears to be higher due to its high MIF values, but designers need to evaluate the cost optimization possibilities for specifc projects.