Thermal and Mechanical Performance of 3D-Printed Excavated Soil Wall Solidified by Alkali-Activated Slag (2026-01)¶

Wall fabrication is an important approach for achieving high-value utilization of excavated soil (ES). To address the issues of inadequate mechanical performance and durability in conventional earthen walls, this study employs alkali-activated technology and 3D printing techniques to fabricate wall specimens. Four types of 3D-printed soil-based walls (PSW) with different solidification formulations, block configurations, and internal filling conditions were designed. Their mechanical properties were systematically investigated, and their thermal performance as wall materials was validated. The thermal and mechanical properties of PSWs were systematically investigated. Comparative analysis revealed that the actual compressive strength of PSW decreased by 6.2 %–39.0 % compared to 3D-printed mortar walls, yet still satisfies the mechanical requirements for low-rise building structures. The equivalent thermal conductivity of PSW ranged from 0.099 to 0.108 W/(K·m), representing a 14.1 %–21.0 % reduction compared to 3D-printed mortar walls. Structural optimization through inclined rib incorporation reduced thermal conductivity by 17.0 % and improved compressive strength by 6.1 %. Furthermore, cavity filling with insulating materials (e.g., polyurethane foam) achieved a 62.7 % reduction in thermal conductivity, enabling compliance with thermal requirements for severe cold regions. PSW demonstrated significant sustainability advantages, with reductions in cost and carbon emissions by 11.5 %–27.4 % and 72.7 %–80.8 %, respectively. This research demonstrates the technical feasibility and environmental-economic benefits of 3D-printed solidified soil walls, highlighting their potential for sustainable construction applications.