Experimental evaluation of mechanical properties of small scale superadobe specimens under compression and flexural loading

The growing demand for affordable, resilient, and sustainable housing highlights the relevance of earth-based methods such as superadobe, especially in developing countries and hazard-prone regions. Despite its increasing adoption, the mechanical behaviour of earthbag components remains insufficiently characterised. This study investigates the compressive and flexural performance of superadobe materials and examines the effects of specimen dimensions as well as the roles of the bag and barbed wire. Thirteen small-scale unconfined compression specimens and thirteen three-point bending specimens were prepared using well-graded clayey sand and local materials. Results, presented as stress-strain and load-displacement diagrams, revealed that favourable aspect ratios and the confining action of the bags increased average compressive strength by about 6.46 times compared to unconfined soil. The bags helped preserve specimen integrity after crushing in compression or cracking in tension, delaying strength loss. Barbed wire strands, by providing continuity between courses, maintained flexural capacity after tensile cracking of the soil. Overall, bags and barbed wire not only improved the compressive strength of rammed earth but also significantly increased specimen ductility. These findings support improved design, numerical modelling, and broader application of superadobe in sustainable construction.