Ultra-compressed earth block stabilized by bio-binder for sustainable building construction

Conventional practices in earth construction, such as cement stabilization and the energyintensive firing of bricks, contribute significantly to carbon emissions due to the processes involved in cement production and kiln operation. Additionally, concerns over the low strength of earth-based materials have limited their broader applications. This research addresses these challenges by implementing ultra-high pressures (200 MPa and 400 MPa) and bio-binders (animal glue and xanthan gum) to enhance earth materials for construction. Unstabilized earth mixture and normal pressure case (20 MPa) are also included in this study for comparison. A customdesigned mold and a specialized production process are developed to fabricate cylindrical earth samples for testing. After undergoing three hours of consolidation and 28 days of curing, unconfined compressive strengths are measured. Scanning electron microscopy is used to investigate the influence of ultra-high pressures and bio-binders on the microstructures of compressed earth blocks. The experimental results demonstrate that animal-glue- and xanthan-gumstabilized samples under ultra-high pressure achieve compressive strengths comparable to traditional fired bricks, while unstabilized samples exhibit the strength of cement-stabilized rammed earth. This research demonstrates that ultra-compression combined with bio-binder stabilization presents a viable strategy for reducing the carbon footprint of earth construction while significantly enhancing the mechanical properties.