Life cycle assessment of geogrid-reinforced unpaved roads

Geogrids are widely employed in road projects as a sustainable solution to reduce base course material and extend service life. This study evaluates the environmental impacts of two representative unpaved road designs: an unreinforced section and a geogrid-reinforced section. Both sections were designed using the Giroud-Han method, and a cradle-to-construction life cycle assessment (LCA) was performed to compare their environmental impacts. The geogrid product was modeled using data from a third-party verified Environmental Product Declaration (EPD). The results indicated that the geogrid-reinforced scenario exhibited lower environmental burdens across nearly all impact categories. Associated uncertainties were assessed using Monte Carlo simulation, and the results showed that uncertainty was largely influenced by the default low-quality gravel data in the ecoinvent database. Sensitivity analysis showed that environmental impacts increased linearly with gravel transport distance, with global warming potential (GWP), fossil fuel potential (FFP), and human toxicity: non-cancer (HTPnc) being the most sensitive impact categories. Comparison of GWP, FFP and HTPnc indicates that the geogrid-reinforced design provided limited benefits at shorter haul distances but achieved greater impact reductions as the haul distance increased. The findings from this study provide stakeholders and policymakers with an evaluation tool to guide sustainable infrastructure planning.