Strength Characteristics of Geopolymer Fly Ash-Stabilized Reclaimed Asphalt Pavement Base Courses

Safe disposal of recycled construction materials and industrial by-products has become a real environmental concern. Reclaimed asphalt pavements (RAP) and fly ash are such materials, among many other recycled materials, highly produced and stockpiled across the world. The reuse of these secondary materials in civil engineering applications in large quantities is always a challenge due to their inferior properties. RAP materials in pavement base courses have proven to be a viable alternative not only to conserve the natural resources but also to reduce the environmental pollution and landfilling. Since RAP is inefficient to be used as a pavement material, they are blended with virgin aggregates (VA) or stabilized with cementitious materials. This study characterizes RAP/VA mixes stabilized with alkali-activated fly ash. The presence of the aged bitumen coat over the RAP aggregates may affect the long-term strength and durability of the design mixes; the mixes meet the strength requirements. Hence, the present study verifies the durability of the mixes by subjecting the specimens to aggressive wet–dry cycles to verify the weight loss. The permanency of the stabilizer/activator is also verified through leachate studies. The comprehensive experimental test results indicated that the RAP/VA mixes are durable and found suitable for the base course applications