Eco-efficiency assessment of long-life asphalt pavement technologies

This paper presents a comprehensive eco-efficiency assessment for six promising long-life asphalt pavement (LLAP) designs as a structural system, including the full-depth (FD), thick asphalt layer (TAL), inverted (Ive), enhanced semi-rigid base (Esemi), composite (CP) and traditional semi-rigid base (Tsemi) asphalt pavement. Results showed that under the baseline design scenario, the Ive, ESemi and CP perform best in terms of greenhouse gas (GHG) emissions, total embodied energy (TEE), and life-cycle cost (LCC), respectively. In most cases of the scenario and uncertainty analyses, ESemi and Ive were the most eco-efficient solutions, although CP may dominate ESemi for a longer design life, whereas the other three designs were dominated by one or more of the abovementioned designs. Among all life-cycle activities, the raw material phase was proved to be the most critical source of GHG (54.2-79.4 %), TEE (41.8-54.9 %), and LCC (72.0-72.9 %), under the system boundary of cradle-to-grave (excluding operation phase). Striking a balance between the thickness of cement-based and asphalt structural layers is the key to achieving sustainable pavement.