Effects of sulfur by-products on the durability and sustainability of asphalt pavement construction: A systematic review

There has been growing interest in utilizing sulfur by-products in asphalt binders and mixtures for pavement construction. Historically explored in the 1970s and shelved in the 1980s due to economic constraints, sulfur-based technologies are now being reconsidered considering current environmental and economic demands. This systematic review aims to assess the current research on incorporating sulfur into asphalt binders and mixtures and its effects on pavement performance, environmental sustainability, and economic feasibility. It conducts a detailed analysis of the existing literature and synthesizes the key findings on the engineering properties, long-term performance, environmental impacts, and safety considerations of sulfur-modified asphalt (SMA) or Sulfur-Extended Asphalt (SEA). The key findings revealed that incorporating sulfur enhanced the Marshall stability, stiffness, and ductility of asphalt mixtures while reducing flow and permanent deformation. However, concerns remain over sulfur's environmental and health impacts, particularly hazardous gas emissions, underscoring the need for clear guidelines, deeper insight into chemical and mechanical interactions, optimized mixing procedures, and effective mitigation strategies. This review outlines these challenges alongside motivations and future directions to guide further research and development. The paper summaries the findings that highlight the potential use of sulfur by-products to modify asphalt binders and mixtures for robust and sustainable pavement road construction.