On the use of recycled polyethylene terephthalate fiber in one-part geopolymer stabilized soft soil: Tensile performance and sustainability analysis

Aiming to promote low-carbon transformation of construction materials and waste upcycling solutions, this study adopted one-part geopolymer (OPG) as a sustainable binder for stabilizing soft soil. The recycled polyethylene terephthalate (RPET) fiber was also incorporated to enhance the stabilized soil’s tensile strength. The effects of fly ash (FA) content, RPET fiber content and length on the tensile performance of the stabilized soil were investigated to reveal the synergistic mechanism between FA and RPET fiber. Results showed that the FA enhanced fiber-matrix deformation compatibility and improved fiber dispersion through its lubrication effects, significantly boosting the contribution of RPET fibers to the improvement of tensile strength of the stabilized soil. Life cycle assessment indicated that OPG-stabilized soil reduced carbon emissions, energy consumption, and costs by 78%, 58%, and 50% compared to ordinary Portland cement (OPC)-stabilized soil. The findings support OPG and RPET fiber's practical application in eco-friendly ground improvement and waste management. • The mechanism by which the incorporation of FA significantly enhances the effectiveness of RPET fiber in increasing the tensile strength of OPG-stabilized soft soil was systematically investigated. • The synergistic effects of FA and RPET fiber enhanced the tensile strength of OPG-stabilized soft soil, with a maximum improvement of up to 106.8%. • A sustainability analysis of OPG-stabilized soil with RPET fiber was conducted using the Life Cycle Assessment (LCA) method and compared to the analysis of OPC-stabilized soil. • Utilizing solid waste and recycled plastics as high-value-added resources offered an eco-friendly solution for ground improvement and waste management.