Performance evaluation and development of sustainable pavement surfaces using ultra-thin geopolymer concrete overlays

Abstract

This study investigates the viability of employing an ultra-thin Geopolymer Concrete (GPC) overlay, synthesized from ground granulated blast-furnace slag (GGBS) and fly ash (FA), as a sustainable white topping for asphalt pavements. The research emphasizes the stress-handling efficacy of GPC under load scenarios typical of lowvolume road traffic. A finite element model (FEM) was meticulously developed using ABAQUS software to simulate the mechanical behaviour of a GPC ultra-thin white topping (UTWT) overlay applied over asphalt substrates. Key design variables, including overlay thickness, elastic modulus, and critical stresses induced by a 51 kN applied load, were systematically analysed. The FEM utilized a 1m x 1m panel configuration for the overlay system. Additionally, a non-linear regression model was formulated to predict critical corner stresses and enhance overlay design optimization. The findings demonstrate that the UTWT overlay effectively reduces stress concentrations and improves load distribution, substantiating its potential as a viable alternative to conventional cement concrete overlays. An increase in GPC layer thickness over asphalt foundations was observed to significantly attenuate critical stress magnitudes. This research positions GGBS-FA-based GPC as a sustainable and structurally proficient alternative for pavement rehabilitation, meeting performance requirements for low-volume roads while promoting long-term sustainability in pavement engineering.