Mechanical behavior evaluation of asphalt mixtures using alternative fillers: a literature review and comparative analysis

This study evaluates the mechanical performance of asphalt mixtures incorporating alternative fillers derived from industrial by-products and waste materials, aiming to promote sustainable pavement engineering. The asphalt layer in flexible pavements is critical for load distribution, water sealing, and surface durability. While traditional fillers like hydrated lime and Portland cement improve mixture properties, environmental concerns drive the search for sustainable alternatives. Through a comprehensive literature review, materials such as hydrated lime, bauxite residue (red mud), rice husk ash, fly ash, steel slag glass powder, and recycled concrete aggregate powder were analyzed based on mechanical tests including Tensile Strength by Diametral Compression (RT), Resilience Modulus (Mr), Modified Lottman, and fatigue testing. Findings reveal that all alternative fillers comply with DNIT-EM 367 (1997) standards and generally exhibit satisfactory or enhanced mechanical behavior compared to conventional fillers. Notably, bauxite residue significantly reduced permanent deformation, while rice husk ash and kaolin processing residues improved moisture resistance. Iron oxide increased stiffness but posed challenges related to mixture flexibility and stress response. The results underscore the potential of these industrial residues as cost-effective, environmentally friendly fillers that contribute to improved pavement performance while reducing reliance on natural resources and minimizing waste disposal impacts. Despite promising laboratory outcomes, further research is needed to establish standardized testing protocols and evaluate long-term field performance to fully validate the practical applicability of these alternative fillers in asphalt mixtures. This approach aligns with sustainable infrastructure development by integrating waste valorization into pavement materials technology.