A systematic review of montmorillonite-asphalt composite materials: Green clay mineral-reinforced asphalt for sustainable pavement solutions

Under the background of pavement engineering driving towards sustainability and resilience, there is an urgent need for high performance and eco friendly asphalt materials. Montmorillonite (MMT) modified asphalt composites arise as a groundbreaking solution, offering integrated advantages in mechanical reinforcement, aging resistance, and environmental decontamination. By utilizing MMT, a natural layered silicate, as a green nano modifier, these composites present a sustainable alternative to conventional polymer modified asphalt, significantly reducing petroleum based additive consumption while enhancing thermal stability and flame retardancy. The unique nanostructure, characterized by exfoliated silicate layers with tunable interlayer space and high specific surface area, enables exceptional oxygen/UV shielding and VOCs adsorption capacities. This review comprehensively examines the fundamental mechanisms governing MMT asphalt interactions, focusing on the synergistic effects of intercalation induced rheological enhancement, tortuous oxygen diffusion pathways, and catalytic pollutant degradation. Key challenges, including low temperature performance trade-offs and incomplete nanolayer exfoliation, are addressed through advanced modification strategies. In addition, given MMT`s significant intrinsic physicochemical variability, clarifying the influence of these fundamental properties on asphalt performance is paramount. The review further discusses the scalable fabrication protocols and machine learning assisted performance prediction models to bridge laboratory innovations with engineering practice. This review aims to offer valuable insights for researchers and engineers working in the fields of green and high performance asphalt pavement construction.