Due to increasingly search for alternative in terms of full or partial substitute for cement, there is need to justify pozzolanic properties of the various pozzolana use in structural work as applied to structural strength of the end product quality. This paper compares and presents analysis of some properties of artificial pozzolana that are common in Niger State, Nigeria: - Rice Husk Ash (RHA), Corn Cob Ash (CCA) and Sheanut Shell Ash (SSA). Laboratory analysis was adopted for the research. The three samples were burnt in open air to produce Ash, chemical composition of all the ashes, setting time as well as the density, workability and compressive strength of the concrete were determined. Each of the Ash was used separately to produce concrete cubes using various replacement levels of 0, 10, 20 and 30 percent of Ordinary Portland Cement (OPC). A total number of 48 cubes were cast from each ash replacement and cured in water for 7, 14, 21 and 28 days respectively. The chemical composition of all the ashes ascertained their pozzolanic properties. The result shows that the density of the concrete cube samples decreased as the percentage replacement of OPC increased. The initial and final setting time increased with increased in the percentage replacement. The compressive strength of all the ashes increases with increase in curing period and decreases with increase in all the ash substitution. There was a sharp decrease in compressive strength beyond 20% in all the ash substitution. The substitution of cement with any of the three ashes in concrete is relatively possible not exceeding 20%.
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