The effective use of portland cement as binder replacement in reactive powder-based hybrid asphalt concrete

Mineral fillers are crucial components of asphalt mixtures, enhancing workability, increasing binder stiffness, and improving overall pavement performance. Those can be suspended in the asphalt binder and stiffened, or assimilated into the aggregate structure, affecting particle contact. Incorporating fillers such as cement powder, in place of traditional rock dust, is gaining traction specifically in hot and humid regions, to enhance asphalt pavement performance. This study explores an innovative approach involving the incorporation of Portland Cement (PC) as a filler through a substantial 40% binder volume replacement in Warm Mix Asphalt (WMA) mixtures, in both virgin and SBS-modified bitumen, comparing its performance to traditional Limestone (LS) filler. The investigation comprehensively assesses various properties, including physical and chemical characteristics of fillers, moisture-induced self-healing, percent of aggregate coating, workability, moisture susceptibility, and fatigue cracking propagation. This is conducted all according to the Superpave® testing methodology. The results revealed that WMA mixtures with PC reactive powder, regarding both PG58-28 and polymer-modified PG58-28 binders, exhibit superior constructability, necessitating less compaction effort for achieving target air voids. Furthermore, PC-based mixtures exhibit enhanced tensile strength, considerable resistance to moisture damage, and notably improved fatigue cracking resistance. These findings collectively support the feasibility of using PC reactive powder in a hybrid WMA asphalt mixtures, offering a sustainable alternative with economic benefits, reduced emissions, and improved pavement durability.