Abrham Gebre (PhD)Betelhem Aziz2024-07-312024-07-312024-06https://etd.aau.edu.et/handle/123456789/3360Concrete became more in demand as the building sector grew. Which leads to ongoing quarrying and causes the depletion of natural resources due to excessive mining of natural sand. Also the increase in demand and consumption of egg leads to waste production which will impact the environment. Utilizing of waste materials will reduces the need for natural aggregate, energy, and environmental damage. This study explores the possibility of substituting sand partially with eggshell in mortar production, with a focus on its effects on compressive strength, flexural strength, and chloride penetration resistance. Eggshells, a readily available waste material, offer a sustainable alternative to traditional sand, addressing both environmental and resource depletion concerns. Mortar samples with varying percentages of eggshell powder replacing sand (0%, 10%, 20%, 25%, and 30%) were prepared and subjected to standard testing procedures. The experimental results indicate a decrease in both compressive and flexural strengths with the inclusion of eggshell, compared to control samples. Specifically, the compressive strength decreased by up to 16%, 38% 44% and 49% with 10%, 20%, 25%, and 30% replacement respectively the flexural strength saw a reduction of up to 7.8%, 22%, 31% and 43% with 10%, 20%, 25%, and 30% replacement respectively. Despite these reductions in mechanical properties, a replacement up to 5% is acceptable. For flexural strength 25% is acceptable. The resistance to chloride penetration increases as the percentage of eggshell increases with 0% and 10% replacement showing similar results and 30% showed the highest increase in chloride penetration. And also, there is a decrease in the density of mortar samples with eggshell than the controlled samples because of the light weight of eggshell which can be used for redaction of the overall weight of the structure.en-USeggshellfine aggregatecompressive strengthflexural strengthchloride penetration resistancemortar.Thesis