Carbon Accounting for Permeable Pavement Based on the Full Life Cycle Approach and Its Application

Conventional pavement in aging communities requires renovation in alignment with global carbon reduction initiatives. This study, centered on upgrading facilities in Guangdong, Hong Kong, and the Macao Greater Bay Area (GBA), utilized the Energy Expert platform to assess the carbon footprint of permeable pavement using life cycle assessment (LCA). The results revealed that the total carbon emission of the 64,065 m² permeable pavement was 7066.21 tCO₂eq. The carbon emission contribution, from highest to lowest, was the production phase, maintenance phase, end-of-life phase, and construction phase. Notably, transportation alone constituted a substantial portion, amounting to 30.15% of total carbon emissions. Compared to traditional pavements, permeable pavement showcased substantial potential for carbon reduction, primarily during the use phase, by enhancing groundwater recharge and mitigating the urban heat island effect, which is critical in reducing the carbon footprint. The estimated total carbon reduction was 853.10 tCO₂eq. Sensitivity analysis highlighted diesel energy use in the maintenance phase (51.20%), transportation of cement raw materials in the production phase (45.80%), and transportation of graded gravel for disposal in the end-of-life phase (3.00%) as key factors. Our findings suggest that adopting specific carbon reduction measures, such as substituting gangue for cement binder, transitioning to manual sweeping, and recycling all discarded materials can achieve notable reductions in the respective phases. These findings contribute to a deeper understanding of the role of permeable pavement in reducing carbon emissions, providing insights for the renovation of aging communities.