Strength-Durability-Sustainability-Based Assessment of Hybrid Fiber-Reinforced Recycled Aggregate Concrete with Ground Granulated Blast Furnace Slag for Whitetopping Application

The rising environmental impact of cement production and depletion of natural aggregates pose significant challenges to sustainable pavement construction. In this study, these concerns are addressed through an evaluation of hybrid fiber-reinforced recycled aggregate concrete (RAC) incorporating ground granulated blast furnace slag (GGBS) for whitetopping applications. Two hybrid fiber combinations were considered—micropolypropylene with macrosteel and microglass with macrosteel. Experimental investigations were conducted to assess compressive strength, flexural toughness, abrasion resistance, and water sorptivity. The inclusion of recycled concrete aggregates alone decreased strength and durability, while GGBS substitution moderately improved performance. However, the addition of hybrid fibers significantly enhanced all properties, enabling RAC mixtures to meet strength and durability requirements and reducing whitetopping thickness by up to 60%. A cradle-to-gate lifecycle assessment demonstrated substantial reductions in cumulative energy demand and carbon dioxide emissions in the designed concrete mixtures. A multicriteria decision-making framework to rank the concrete mixtures based on mechanical, durability, and sustainability parameters was developed. This study confirms the feasibility of producing sustainable pavement concrete with sufficient structural integrity using recycled materials and industrial byproducts, contributing to circular economy goals.