Track: Environmental Engineering

Abstract

This work presents the results of the evaluation of Sesame Stalk Ash (SSA) as partial replacement of ordinary portland cement in concrete. SSA was used to replace OPC by weight ranging from 0 to 20 % at interval of 5 % replacement using the concrete mix ratio (1:2:4). Experimental tests such as setting times, consistency, soundness, XRF and slump were carried out to determined the properties of SSA-cement paste and fresh concrete respectively. Likewise, compressive strength test was carried out on 100 mm cubes after 7, 14 and 28 days curing. However, from the results obtained, it indicates that both the Initial and Final Setting Times increases with an increase in the percentage of Sesame Stalk Ash (SSA). The values of soundness obtained at each replacement levels falls within the acceptable limit specified by BS EN 196-3 (1995). Also, XRF conducted on SSA indicates that the content of Silica (SiO₂) is 11.636 %. Aluminium oxide (Al₂O₃) is 3.005 % and Ferrous Oxide (Fe₂O₃) is 0.982 % sums up to (15.623 %) which is less than the minimum value of a good pozzolanic materials. Therefore, SSA has a low pozzolanic reactivity (ASTM 618, 2008). It was also comfirmrd from the research that the Compressive Strength of concrete decreases with an increase in SSA contents. On the other hand, it increases as the curing age increases. The 5, 10, 15 and 20 % replacement of cement with SSA respectively gives a Compressive Strength of 15.55 N/mm², 9.08 N/ mm², 6.00 N/mm² and 5.50 N/mm² at 28 days of curing. However, the 5 % replacement gives the Optimum Compressive Strength of 15.55 N/mm².