Effects of Eggshells Ash (ESA) on the Setting Time of Cement
Admixture properties of eggshells ash (ESA), with a focus on the setting time, were investigated. ESA was obtained by incinerating fowls’ eggshells to ash. The ash was sieved through 75μm sieve. The ash passing the 75 μm sieve was used in the investigation. Consistency test was carried out to establish the quantity of water required to constitute a standard cement paste of normal consistency in accordance to BS 12: 1991 . Cement-eggshells ash (CESA) paste was constituted using 0%, 0.1%, 0.5%, 1%, 1.5%, 2.0% and 2.5% of ESA by weight of cement. Setting time test was conducted on the CESA paste in accordance to BS 12:1991 n. Results show that the addition of ESA to the ordinary Portland cement (OPC) decreases the setting time of the cement. Conclusions drawn are that ESA is an accelerator; the higher the ESA content, the faster the rate of setting; all contents of the of the ESA employed in this investigation satisfy the setting time requirements of BS 12:1991  for both the initial and final setting times. Thus, it is recommended that ESA can be used as an accelerator in concrete.