Influence of Higher Volumes of Clay Pozzolana Replacement Levels on Some Technical Properties of Cement Pastes and Mortars

Most of the investigations on the utilization of clay pozzolana are limited to about 30% of the material consideration in Portland cement. In this study clay pozzolana was used to replace cement between 30% and 50%. Clay pozzolana was analyzed to determine their chemical and mineralogical composition. Both binder paste and mortar were formulated and results compared to unblended cement system. Some selected technical properties such as water demand, setting times and strength determination were performed. The work also determined the economic benefits of the optimum pozzolana mortars and compared with the unblended mortar mix. Test results indicated that cement-pozzolana system demanded high water, caused an extended setting times as well as strength reduction. Although the strength values were reduced, optimum mix proportions were very good for the formulation of ASTM type M and type S mortar class.