Mechanical and water absorption performance of sheep wool-reinforced compressed stabilized earth bricks

The object of research is the evaluation of the mechanical performance and water absorption characteristics of compressed stabilized earth bricks (CSEBs) in considering varying contents of cement and sheep wool fiber (SWF). The experimental work was conducted on bricks produced using locally sourced raw materials in Kabul, Afghanistan. Method. In this study, the bricks were prepared using 28% clay-silt and 72% machine crushed sand as the primary raw materials. Sheep wool fiber (SWF) was incorporated as a reinforcement at contents of 0%, 0.05%, 0.1%, 0.2%, 0.3%, and 0.4% by weight of the soil mix, while ordinary Portland cement (OPC) was used as a stabilizing agent at dosages of 0%, 5%, and 10%. Mechanical performance was evaluated through tests on dry-state and wet-state compressive strength, as well as flexural tensile strength. Dry-state compressive strength was assessed for all mix designs, including combinations with 0% cement and 0% SWF, as well as varying proportions of cement and SWF, to determine the influence of these additives on structural performance. For the wet-state compressive strength test, a constant cement content of 10% was used with varying SWF contents to evaluate the effect of SWF on the retention of compressive strength under saturated conditions. Flexural tensile strength (or modulus of rupture) was assessed across mixtures with 0% cement and 0% SWF, as well as combinations with varying amounts of cement and SWF, to investigate the influence of these components on flexural resistance. For water absorption behavior, total water absorption and capillary water absorption tests were conducted using a constant cement content of 10% and varying SWF contents, to determine the impact of fiber inclusion on the bricks' water absorption characteristics. Result. The study found that the inclusion of SWF in CSEBs has a negative impact on dry compressive strength, with increasing SWF content leading to a reduction in strength. However, SWF inclusion shows a positive effect in preserving compressive strength under wet conditions and significantly reduces capillary water absorption compared to bricks without SWF. The addition of SWF up to 0.3% improves flexural tensile strength; however, exceeding this dosage leads to a decrease in flexural performance and the development of horizontal cracks in the bricks. Overall, the findings demonstrate that CSEBs incorporating appropriate proportions of cement and SWF show mechanical performance and water absorption characteristics that meet or exceed the requirements of relevant standards. This indicates their capability as sustainable, structurally sound, and load-bearing construction materials suitable for use in a variety of building applications.