Life cycle energy consumption by roads and associated interpretative analysis of sustainable policies

Abstract

Large-scale road networks consume numerous energy-intensive products over their life cycle. However, road energy consumption remains poorly understood due to the incomplete system boundaries of methodologies and inadequate databases for quantitative assessments. To provide a holistic account of roads’ impacts on energy conservation, this study investigated overall energy consumption by a road located in Inner Mongolia, China, in light of life cycle assessment (LCA). The three structural road layers model and localized databases were developed as supplements to methodologies and data of the LCA approach. The results show that 1 km of the road consumes 11.38 TJ (with an uncertainty range of −3.75%–34%), more than half of which flows into the surface layer (5.16 TJ), followed by the subgrade (4.87 TJ) and base layers (1.35 TJ). From a life cycle perspective, material extraction was identified as the major energy consumer (6.27 TJ); road service and construction used 3.01 TJ (26.59%) and 1.74 TJ (15.37%), respectively. The reclamation phase consumed 0.30 TJ with a percentage of 2.65%. It is suggested that preventive maintenance treatments and binder production procedures are critical for energy consumption mitigation, and the construction of the base layer and subgrade should address the distance management of raw material transportation. Advanced construction techniques, renewable energy resources and recycled materials applications are three highly recommended aspects of policy interpretations. This study not only facilitates more complete and accurate assessments of means of alleviating intensive energy consumption induced by roads, but also provides valuable information for enhancing sustainable road development.