Experimental Study on the Influence of Mogadishu Manufactured Sand on the Engineering Properties of Concrete.

Abstract

Due to the increasing demand for sand for construction activities across the world including Mogadishu Somalia, natural sand resources are growingly used up and its price is becoming increasingly high. This study aimed to research the influence of Mogadishu manufactured sand on the engineering properties of concrete. Manufactured sand refers to fine aggregate which is less than 4.75mm. In this research, Mogadishu Manufactured sand was refined from the crushed limestone rock as a replacement for river sand. The overall objective of the study was to evaluate the influence of Mogadishu manufactured sand on the engineering properties of concrete; the specific objectives were to examine the properties of plastic and hardened concrete; to investigate the durability of concrete with Mogadishu manufactured sand. The study used manufactured sand incomplete and complete replacement for natural sand. The replacement level were 0% (pure river sand), 25%, 50%, 75% and 100% for constant water-cement ratio for all mixes. The basic aggregate tests considered were sieve analysis for fine and coarse aggregate, specific gravity, and water absorption was also done. Design mix of class 30 concrete having mix amount for both natural and manufactured sand was considered for the workability test (slump test and compaction factor test). The splitting tensile strength test and compressive strength test for 28 and 56 days was done. The study, in addition, considered durability testing by exposing the concrete to sodium chloride, magnesium sulphate and sulphuric acid. Then final assessment was done to determine how these chemicals affected the concrete after 28 and 56 days of immersion. It was found that the slump and compaction factor values of the concrete mix with Mogadishu manufactured sand decreased compared to that of conventional concrete. Concrete with Mogadishu manufactured sand significantly improves the strength properties of the concrete by up to 25%. This was attributed to the presence of micro fines in the manufactured sand generated from limestone rock. When exposed to sulphuric acid, magnesium sulphate and sodium chloride, the durability of concrete with manufactured sand were improved as compared to that of normal concrete with river sand. Hence from the experimental investigations, it is concluded that Mogadishu manufactured sand can be partially utilized as fine aggregate in concrete production of construction activities.