Efficiency of waste eggshell as powder on some mortar's fresh and hardened properties

Abstract

This research checked the efficiency of using eggshell once as powder replaced partially the cement in mortar's matrix. Effect of each state of waste eggshell has been studied on some fresh and hardened properties of cement mortars. Level of replacement with either eggshell powder or eggshell fine aggregate are; 0%, 2%, 4%, 5.0 %, 7 % 8.0% and 10% (by weight of cement). The resulting mortars was compared for setting time (initial and final), slump and fresh density and hardened properties like; dry density, compressive and flexural tensile strength, water absorption and porosity. Results showed that eggshell powder work like accelerators, it reduced both initial and final setting time. The difference in the initial setting time is about 9.3 to 37.0% for 0% to 10% of ESP ratio respectively. While the difference in the final setting time is about 3.3% to 25.6% for 0% to 10% of ESP ratio. At early age (7 day) incorporating led ESP into mortar led to higher compressive strength than control one. While at late age (28 and 56 days) the rate of strength is increasing decrease. Flexural strength increased with increasing of ESP% up to 5%, then began to decrease for higher content. also ESP led to decrease both of % absorption and %porosity especially for low content up to 5%.