Physical-Mechanical Properties of Sand from Various Sandpits in the North West Region and Their Recommended Domains of Application

Abstract

Sand is widely used in the Northwest Region of Cameroon and it is over 38% of the total aggregate quantity in concrete and the only aggregate in mortar, thus has a significant impact on their properties. The inability to make alternative sand choices for use in projects and the inability of contractors to attain 25 mega Pascal (MPa) compressive strength among others, call for concern, necessitating this study to classify the sands according to their physical-mechanical properties and suitability for various works. Based in Mezam, the study required identification tests for the sands. Wum, Mbengwi, Ndop, Chomba and Mbatu sands were studied. Concrete was formulated for 25 MPa strength and mortar on a ratio of 3:1:0.75 for sand, cement and water respectively, to assess the contribution of these sands in concrete and mortar and to find their specific qualities. Tests indicated that Wum sand was densest (specific gravity 2.548 t/m3) and Mbatu sand lightest (specific gravity 2.486 t/m3). Gradation showed that Wum sand had the largest grains (Mfs 2.93) while Mbatu sand had the finest (Mfs 2.62). Concrete was formulated with water-cement ratio of 0.56 for the sands and had 26.64, 24.4, 20.59, 21.66 and 17.33 MPa resistance respectively at 28-days of curing. The mortar gave 25.33, 20.62, 13.01, 19.17 and 15.99 MPa respectively for the sources after 14-days of curing cubes of 70 mm sides. These proved that Wum sand was best for structural uses and Ndop sand for light loads. Mbengwi and Chomba sands should be washed while Mbatu sand should at best be mixed with Wum sand.