Influence of Bed Ash and Fly Ash Replacement in Mortars

The study evaluates the influence of fly ash and bottom ash as partial cement substitutes in mortars by studying\ud the particle size distribution, consistency, flow, fresh density, air content, compressive strength and flexural\ud strength characteristics. The results revealed that fly ash and cement had relatively the same particle size\ud distribution unlike bottom ash. In the fresh state, as the amount of pozzolans increased in the mixtures, the\ud mortars showed an enhancement in workability, were susceptible to water loss by bleeding, and exhibited a\ud decline in fresh density. The early strength gains of the fly ash samples were low but reached higher than the\ud control after 28 days of curing. The flexural strength increased as the fly ash content rose to reach a maximum at\ud 20 % replacement. However, the 2-day compressive strength of bottom ash samples was higher than the control\ud but decreased after 28 days of curing while the flexural strength declined with addition of bottom ash except at 5\ud % substitution