This paper aims at assessing the influence of using Sesame straw ash (SSA) blended with rice husk ash (RHA) as an alternative for cement in grade 20 concrete. Setting times, soundness and consistency tests were carried out on SSA-RHA-cement paste, while slump (workability) test and strengths tests were conducted on hardened concrete. Influences of SS-RHA on concrete and cement paste were examined for the addition of 0, 5, 10, 15, 20 and 25 % by weight of cement, and 3, 7, 28, 56 and 90 days were considered for the curing period. The result shows that the addition of SSA-RHA increases the workability (slump) of concrete decreases, but consistency, soundness and setting times of cement paste blended with SSA-RHA increase as SSA-RHA goes up. Moreover, the splitting tensile strength and compressive strength of SSA-RHA-concrete steps-up as the curing time increases and they decrease as the quantity of SSA-RHA increases. It was established at 28 days of curing, that the concrete’s strength made with 15 % SSA-RHA went beyond the target strength of 20 N/mm2. In addition, the densities of SSA-RHA-concrete samples fall within the limits of 2200 kg/m3 to 2600 kg/m3. Finally, it was settled that the maximum quantity of SSA-RHA should not be more than 10 % for the production of concrete.
Key words: Sesame straw ash (SSA), Cement, workability, compressive strength and Rice husk Ash
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