Optimization of natural fibre length in bacterial cement mortar using TOPSIS for enhanced mechanical properties

The use of natural fibers has gained popularity as a sustainable substitute for synthetic fibers in various applications. This study investigates the optimization of natural fiber length in bacterial cement mortar to enhance its mechanical properties, with a focus on Banana and Kenaf fibers. Cement mortar samples were prepared with varying fiber lengths (0.5–3.5 cm) at a 2% fiber content by weight of cement, both with and without the inclusion of bacterial strains Bacillus cereus and Vibrio natriegens was in a ratio of 1:1.25 and the mechanical performance was evaluated through compressive, flexural, and split tensile strength tests. The Analytic Hierarchy Process (AHP) was employed to assign weights to each mechanical property, and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method was utilized to determine the optimal fiber length. The results showed that incorporating natural fibers significantly improved the mechanical properties of cement mortar, with the most significant enhancements observed in samples treated with bacteria. The optimal fiber length was determined to be 2.5 cm for both banana and Kenaf fibers with the addition of bacteria, yielding the highest strength values across all the mechanical tests. These findings demonstrate the synergistic benefits of combining natural fibers and bacterial treatment, offering a sustainable approach to improving the performance of cementitious materials for construction applications.