Comparative study of Giciye Kayumbu and Rusine sand to the compressive strength of concrete Case of Kigali Gasabo Rwanda

Abstract

The use of high-quality sand is crucial for maintaining the compressive strength of composite structures, which is essential for the stability of buildings and infrastructure. Poor-quality sand, characterized by excessive silt, clay, or other impurities, can weaken the bond between particles and aggregates in concrete. This weakened bonding reduces the overall strength of the concrete, making it prone to cracking and diminishing its load-bearing capacity. Laboratory tests were conducted to determine the suitability of different types of sand for use in construction. The results indicate that Kayumbu sand outperforms both Rusine and Giciye sands. Kayumbu sand is a coarse variety with a fineness modulus exceeding 2.9 and a sand equivalent of 96.34%. Its compressive strength was measured at 26.47 MPa at 7 days and 40.21 MPa at 28 days, demonstrating its superior performance. In comparison, Giciye sand, also coarse sand with a fineness modulus above 2.9 and a sand equivalent of 91.22%, showed lower compressive strength values of 21.84 MPa at 7 days and 32.58 MPa at 28 days. Although Giciye sand is better than Rusine, it does not match the strength characteristics of Kayumbu sand. Rusine sand, the least favorable among the three, is medium sand with a fineness modulus ranging between 2.6 and 2.9 and a sand equivalent of 88.46%. It exhibited compressive strengths of 17.01 MPa at 7 days and 27.22 MPa at 28 days, reflecting its reduced quality due to higher clay and silt content. Based on the laboratory analysis and interpretation of these results, Kayumbu sand is the preferred choice for use in construction. It offers the highest compressive strength and overall performance, making it the most suitable sand for construction purposes compared to Rusine and Giciye sands.