Life cycle analysis of decarbonization strategies for asphalt mixtures in Saudi Arabia

This study was initiated with the goal of conducting a cradle-to-gate Life Cycle Assessment (LCA) of asphalt mixtures in the Kingdom of Saudi Arabia's (KSA). The paper focused on assessing the environmental impacts of asphalt mixtures produced with and without Reclaimed Asphalt Pavement (RAP) materials, and the use of Warm Mix Asphalt (WMA) technologies to help reduce mixing temperatures. The study also involved assessing the sensitivity of asphalt mixtures' environmental impacts (mainly global warming as an example) to changes in aggregates and binder (the two main constituents of an asphalt mix) transport distances, replacement of oil/natural gas produced electricity with solar electricity, and replacement of diesel burner fuel with natural gas. Asphalt mix data was collected from different plants throughout the KSA using a survey questionnaire. The assessment showed that the use of RAP in asphalt mixtures led to significant reductions (by up to 17% when using 35% RAP) in the environmental impacts of asphalt mixtures. When combining RAP and WMA technologies a reduction of 20% in environmental impacts can be attained. The assessment also showed that replacing diesel fuel with natural gas, and adding of 35% RAP into asphalt mixtures leads to a reduction of 47.7% in global warming potential. • RAP usage in asphalt mixtures reduces environmental impacts by up to 17%. • Combining RAP and WMA lowers environmental impacts by about 20%. • Aggregates transport distance increases emissions; RAP offsets some of these impacts. • Binder transport has less impact on emissions than aggregates transport. • Switching to natural gas cuts asphalt mixture global warming potential by 47.7%.