Evaluation of MIF/LCR through laboratory test for polypropylene and polyester biaxial geogrid

This study presents a comprehensive evaluation of Modulus Improvement Factors (MIF) and Layer Coefficient Ratios (LCR) for polypropylene (PP) and polyester (PET) biaxial geogrids aimed at improving the performance of flexible pavements. Large-scale laboratory experiments were conducted under varying subgrade California Bearing Ratio (CBR) conditions to assess the structural contribution of geogrid reinforcement within the pavement layers. The geogrids - PP 3030, PET 4040, and PET 8080 - demonstrated noticeable enhancement in pavement stiffness and resilient modulus. PET geogrids, particularly those with higher tensile strength, exhibited superior performance compared to PP geogrids. Reinforcement benefits were more pronounced in weaker subgrade conditions and gradually reduced as subgrade strength increased. Improvements in MIF and LCR values suggest the potential for reducing pavement layer thickness while maintaining durability and structural integrity. The study provides useful guidance for geogrid selection and placement in pavement design and highlights the role of geosynthetics in developing sustainable, cost-effective infrastructure solutions.