Effect of binder type and curing conditions on the mechanical and durability performance of earth‐based 3D ‐printed concrete

Abstract This study investigates the influence of binder type and curing conditions on the performance of earth (soil)‐based 3D printed concrete (3DPC). Incorporating natural soil as a fine aggregate enhanced the extrudability and buildability of 3DPC; however, the combined effects of binder type and curing regime are insufficiently understood. To address this research gap, three curing conditions: ambient (A), burlap plus sealed (BS), and water (W) were evaluated for three binder systems: C (100% cement), F30 (30% cement replacement with fly ash), and G30 (30% cement replacement with ground granulated blast‐furnace slag (GGBS)). All mixes contained 50% sand and 50% soil as fine aggregates. Compressive strength, interlayer bond breaking load (BBL), water absorption, porosity, sorptivity, and dimensional stability were assessed, while X‐ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were employed to examine the microstructure. W‐cured specimens exhibited the highest compressive strength and BBL, followed by BS and A curing. The same trend was observed for water absorption, porosity, and sorptivity, indicating enhanced hydration and a refined pore structure. At 55 days, A and BS curing produced contraction, whereas W curing resulted in expansion. XRD revealed lower alite and portlandite peak intensities in W‐cured specimens, confirming a higher degree of hydration, which was further supported by the denser microstructure observed in FESEM images. Among the mixes, F30 and G30 required W curing for optimal performance, whereas mix C achieved comparable performance under BS and W curing. Overall, the findings demonstrate that W curing enhances the structural integrity and durability of earth‐based 3DPC, making it an effective post‐printing curing strategy.