Effects of Sesame Straw Ash as a Substitute for Cement on Strength Characteristics of Concrete

Abstract

Concrete is broadly used as a building material across the globe, and its use is raising the need of cement in the construction industries. High price of cement and environmental debasement are the driving problems forcing the researchers to come up with alternative materials from large volumes of agricultural wastes as a partial replacement for cement. This study aims at recycling agricultural waste ash (i.e.  Sesame straw ash) as a substitute for cement in the production of sustainable and environmentally friendly greener concrete. Preliminary tests on constituent materials were conducted in order to find out their physical properties. Influences of sesame straw ash (SSA) on cement paste were looked into for addition of 0, 5, 10, 15, 20 and 25 % by weight of cement. The Compressive and flexural strengths as well as the slump of concrete made with different portions of SSA (i.e. 0 – 25 %) were investigated. A 100 mm cubes and 100 mm X 100 mm X 450 mm beams of SSA-concrete were tested for compressive and flexural strengths at 3, 7, 28, 56 and 90 days of curing in line with procedure outlined in BS 1881-116: (1983) and BS 1881-118: (1983) respectively. The outcomes of the workability test show that as the portion of SSA increases the workability a fresh concrete decreases, but consistency, setting times, and soundness of SSA-cement paste increase as the portion of SSA increases. However, the strengths of SSA-concrete increase as the duration of curing increases, and decrease as the portion of SSA increases. It was detected that the strength of concrete produced with 10 % SSA content was beyond the designed strength of 20 N/mm² at 28 days of curing. In addition, the densities of SSA-concrete samples fall within the limits of 2200 kg/m³ to 2600 kg/m³. Finally, it was concluded that the maximum amount of SSA to be used should not exceed 10 % replacement in concrete production.