Physical and mechanical properties of adobe bricks reinforced by natural additives, a case study of alfalfa fibers

Abstract

The primary objective of this study is to determine the impact of alfalfa fiber on the physicomechanical properties of adobe bricks. The soil and fibers utilized in this research as raw materials were obtained from Ouled Mbarek, a village located in the north-central region of Morocco. Comprehensive tests were conducted on the raw materials for characterization, including mineralogical examination, geotechnical assessment, and microstructural analysis. The adobe samples underwent thorough examination, with a focus on damage, fracture behavior and fire resistance. The inclusion of alfalfa fiber, containing hydrophilic compounds such as quasi-crystalline cellulose and hemicelluloses, resulted in increased water absorption and significant porosity due to air entrapment during mixing. Furthermore, the introduction of small amounts of alfalfa fiber led to an enhancement in the mechanical properties of the adobes, showcasing noTable compressive and flexural strength reaching 8.28 MPa and 1.83 MPa, respectively. This improvement was attributed to the strong adhesion between the added fibers and the clay matrix, significantly reducing crack propagation within the composite material. The high tensile strength of alfalfa fibers, stemming from their cellulose content, also played a crucial role in the improved mechanical performance. Consequently, adobes reinforced with such fibers exhibit promising characteristics as cost-effective construction materials in arid and semi-arid regions