Adil Zekaria (PhD0Tewodros Tilahun2024-09-032024-09-032023-09https://etd.aau.edu.et/handle/123456789/3446The paper aims to investigate the influence of incorporating PALF (pineapple leaf fiber) on the mechanical properties of concrete, with a particular focus on the aspect ratio of PALF. This study has to search thoroughly into how varying the aspect ratio of PALF affects the overall performance of concrete as a construction material. The research methodology involves incorporating different aspect ratios of PALF into concrete mixtures, followed by a thorough examination of the resulting mechanical properties. The aspect ratio, which is the ratio of the length to the diameter or width of the PALF fibers, is a critical parameter to study because it can significantly impact the behavior of the composite material. The study will employ various mechanical tests, such as tensile strength, compressive strength and flexural strength, to assess how the different aspect ratios of PALF affect these properties. Additionally, the work will investigate the durability and long-term performance of concrete with PALF reinforcements, considering factors like moisture absorption and aging. Furthermore, the paper will investigate into the implications of the findings for practical applications in the construction industry. Understanding how the aspect ratio of PALF influences concrete's mechanical properties can provide valuable insights for designing sustainable and highperformance concrete composites. In addition to the investigation of PALF's impact on concrete properties, this research shows the influence of sodium hydroxide (NaOH) treatments on enhancing PALF's properties. These treatments are important to mitigate the hydrophilic nature of the fibers, thereby improving their compatibility with hydrophobic fibers within the concrete matrix. The study systematically analyzes the effects of different concentrations of NaOH on the PALF fibers, specifically Alkali 1 wt., Alkali 2 wt., Alkali 4 wt., and Alkali 8 wt. The concrete samples are subjected to testing at different time intervals: the 7th day (representing the initial stage) and the 28th day (representing the final settling period). Moreover, this investigation is carried out in conjunction with varying aspect ratios of PALF, which include 150, 450, 750, and 1050. the result show that 150 is shown an incremental improvement when compared to the control mix and 450 is the optimum amount of PALF to enhance all three mechanical properties in the other way 1050 aspect ratio showing a significant decrease in strength and the 750 aspect ratio exhibiting a decline compared to the control mix.en-UScompressive strengthconcreteflexural strengthsplit tensile strengthmechanical propertychemical compositionaspect ratiopineapple leaf fiber (PALF).Thesis