In Situ Evaluation of Performance of Different Geogrids Laid in Base Layers of Pavements

Geogrids are increasingly vital for sustainable pavement construction, offering savings in construction time and natural aggregates. Beyond traditional ground improvement, they now enhance granular layer properties, characterized by the Modulus Improvement Factor (MIF) and Layer Coefficient Ratio (LCR). However, MIF/LCR values vary significantly based on material, manufacturer, and reinforcement location (subgrade, base, or subbase). This demands meticulous selection during design and rigorous in situ validation. Field tests show alarming MIF variability (1.2–3.6, with over 150% standard deviation), a critical concern as design hinges on these parameters; even slight deviations can lead to under-designed pavements and costly rework if parameters aren't met on-site. Furthermore, physical damage (up to 30%) to geogrids has been observed post construction traffic. This damage depends on placement location. Therefore, in situ performance, construction traffic impact, and durability must be comprehensively evaluated alongside laboratory MIF/LCR to ensure robust and economical pavement designs. This paper offers guidance on geogrid selection, performance, and durability.