Suitability of Crushed Manufactured Sand for Replacement of Natural River Sand to Produce C-25 Concrete

The global consumption of natural sand is very high, due to the extensive use of concrete or mortar. The fine and coarse aggregates generally occupy 60% to 75% concrete volume (70% to 85% by mass) and strongly influence the concrete’s fresh and hardened properties. Now a day’s sand is becoming a very scarce material. Natural sand deposits are being depleted and causing serious threats to the environment and society. The culture of using alternative ingredients to produce materials is weak in Ethiopia. Around Jimma town, quality sand is not readily available and it is transported from Worabe, Gambella, and Chewaka that needs high transportation costs. In this situation, research began for an inexpensive and easily available alternative material to natural sand. The main objective of this study was aimed to determine the fresh and hardened properties of C-25 concrete by replacing natural sand with manufactured sand in Jimma town. This experimental study was conducted by preparing three concrete cubes for each percentage replacement. The replacement was done at 0%, 10%, 20%, 40%, 60%, and 100%. According to this study, the slump values for the above percentage replacement were 48.91 mm, 45.23 mm, 38.98 mm, 32.56 mm, and 26.14 mm respectively. The compressive strengths were 27.08 MPa, 29.34 MPa, 31.25 MPa, 27.25 MPa, and 29.22 MPa, and the flexural strengths were 3.28 MPa, 3.35 MPa, 4.37 MPa, 3.26 MPa, and 4.26 MPa respectively. The maximum compressive strength was obtained at 40% replacement with the corresponding compressive and flexural strengths were 31.25 MPa and 4.37 MPa respectively. From this result it is concluded that manufactured sand can be used as natural sand partial and fully replacement