Gel ice packs as a sustainable additive for geopolymer-stabilized soft clay
摘要
Waste gel ice packs, commonly used for food preservation, pose significant environmental risks due to the release of microplastics and their non-biodegradable nature. This study presents a novel and sustainable approach by repurposing these waste gel ice packs as a solvent in the alkaline activator solution for geopolymer synthesis, specifically for the purpose of soft clay stabilization. We used fly ash as a binder with sodium hydroxide solutions of varying concentrations and their combinations with sodium silicate as activators, and systematically investigated the effects of using gel ice packs on the mechanical properties of both the geopolymer binder and the resulting geopolymer-stabilized soft clay. The results demonstrate that geopolymers incorporating gel ice packs achieved compressive strength (qu) and P-wave velocity (Vp) values 1.2 times or more higher than those with conventional alkaline activators. Microstructural analyses suggest that polymer-induced bonds serve as pore-filling bridges, which densify the geopolymer matrix. When applied to soft clay, the positive effect of the gel ice packs was also evident. The stabilized soft clay reached a peak qu and Vp comparable to cement-stabilized soils with 10–15% cement content, with the measured qu meeting the criteria for deep mixing applications in civil engineering. While the effect of gel ice packs on soft clay was less pronounced due to complex interactions with clay minerals, this study provides clear experimental evidence that waste gel ice packs can serve as an effective water substitute.