Binder chemistry and its impact on geopolymer compaction: predicting compaction parameters

Abstract

Soil stabilization enhances the engineering performance of weak soil [1], [2]. Chemical stabilization is a common method that incorporates additives to form strong interparticle bonds [2]. Traditional binders like ordinary Portland cement (OPC) and lime have been widely used for stabilization, but their production causes about 7% of global greenhouse gas emissions and 11% of energy intake [1], [2], [3]. Geopolymer, which is also referred to as alkali-activated binders (AAB), is a sustainable alternative to OPC in soil stabilization [1], [2], [4], [5]. Geopolymer involves the alkali activation of aluminosilicate precursors like fly ash (FA), rice husk ash (RHA), and ground granulated blast furnace slag (GGBS) [1], [2], [3]. The use of geopolymers enables a substantial reduction in process-related carbon emissions, approximately 60-80% compared to conventional OPC production [4]. Each precursor contains a unique combination of chemical compounds that strongly influences the geopolymerization reactions and the resulting material properties. Binder chemistry governs geopolymer performance through major oxides such as SiO₂, Al₂O₃, CaO, Na/Al, and Si/Al ratios, which influence geopolymerization and gel formation [1], [5]. Key geotechnical parameters like maximum dry density (MDD) and optimum moisture content (OMC) help to evaluate stabilization efficiency [1]. However, predicting these parameters from binder chemistry remains complex. Instead of relying on random trial-and-error to determine the optimal composition, it is essential to establish a systematic mechanism for formulating effective soil reinforcement. Therefore, this study aims to develop a standardized predictive model to estimate compliance with required mechanical properties, moving beyond inefficient trial-and-error methods [1], [2].