Experimental and analytical study on tensile strength of short-fiber-reinforced adobe (SFRA)

The exploration of reinforcing adobe with fibers is pivotal in revolutionizing sustainable construction methods and fortifying the resilience of traditional building materials. This study delves into the impact of incorporating three reinforcement fiber types—glass, polyester, and polypropylene, featuring lengths of 6, 12, and 18mm, and weight percentages of 0.5, 1, and 1.5—on the direct tensile strength of adobe. Additionally, an analytical model based on the modified rule of mixtures was utilized, both with and without porosity consideration, to predict the tensile strength of reinforced adobe. The results indicate that an increase in fiber length and percentage generally augments the tensile strength of samples across all three fiber types, except in cases where excessive elevation of these parameters disrupts proper fiber/mortar adhesion. Notably, samples reinforced with polypropylene fibers exhibited higher tensile strength, with a peak value of 0.69 MPa (using 6mm fibers at 1.5 wt.%), while the lowest value at 0.31 MPa was observed in the sample reinforced with 6mm glass fiber at 0.5 wt.%. The theoretical model yields acceptable predictions for polyester and polypropylene-reinforced samples, with average prediction percentage errors of 16.5% and 13%, respectively, when porosity is considered and samples with excessive fiber length and percentage values are excluded.