Sustainable cement alternatives utilizing geopolymer for use in full depth reclamation of asphalt pavements
Omar Alsanusi Amer, Prasada Rao Rangaraju, Harish Konduru, Haitham Zeidan Hussein
Abstract
This laboratory study investigates the feasibility of using geopolymer-based stabilization of base soil and reclaimed asphalt pavements (RAP) to fully replace cement in road rehabilitation projects. Geopolymer is an environment-friendly material that is based on the alkaline activation of aluminosilicate precursors. The performance of Portland cement as a chemical stabilizer for the full depth reclamation (FDR) of asphalt pavements is well established. However, Portland cement manufacturing has a high carbon footprint and other significant environmental impacts. Furthermore, there is a shortage of cement available for FDR projects across many country regions. Simultaneously, there is a strong motivation to explore various industrial wastes such as ponded ash, slag, ground glass fibers, etc., as replacements for Portland cement in construction. Therefore, a geopolymer based on ground glass fibers (GGF), either separately or combined with ponded fly ash (PFA) or slag (S), was studied to replace cement in FDR. All mixtures were tested for unconfined compressive strength (UCS), flexural strength, and drying shrinkage, wetting/drying, freezing/thawing, and tube suction tests. The results showed promising performance of geopolymer-based stabilized mixtures as compared to control. However, some test methods related to FDR with cement need to be modified to suit the mixtures of FDR with geopolymer.