Performance Evaluation of Raw and Calcined Eggshell as Alternative Fillers in Cement Mortar

The construction industry significantly contributes to greenhouse gas emissions and natural resource depletion through cement manufacturing and extensive river sand extraction. Meanwhile, abundance amount of chicken eggshells waste was continuously disposed in landfill without any treatment. Incorporating eggshells as a fine filler in cement mortar provides a circular strategy that may enhance product performance while reduce environmental burdens which is in line with Sustainable Development Goals (SDG). This study examines the effect of chicken eggshells filler on the mechanical, durability and microstructural properties of conventional mortar. The mortar mixtures were prepared with 10, 20, and 30% volumetric replacement of fine aggregate by eggshells were tested for compressive strength, carbonation depth, sorptivity, and microstructure. The results showed that mortar containing 20% ground eggshell achieve highest performed in compressive strength, lower sorptivity and lower carbonation depth compared to conventional mortar. This results attributed by improved particle packing, and pore refinement. In contrast, mortars incorporating calcined eggshells exhibited lower compressive strength and poorer durability performance due to high calcium oxide content. The findings demonstrate that raw eggshell waste may utilized as an alternative filler to improve mortar performance while supporting the beneficial reuse of agricultural waste and reducing the demanding of natural resources. This approach provides a practical pathway towards more sustainable and resource efficient cement-based construction.