Investigating sand quality effect on concrete strength: A case of debre markos and its vicinities

This research aimed to investigating sand quality effect on compressive strength of concrete. All sand samples were tested for silt and clay contents, organic impurities and chemical composition in accordance with ASTM and concrete cubes were casted with mix ratio of 1:2:3 and tested for compressive strength at age of 7 and 28 days. Aliyas (5.33%) and Kuye (12.18%) sand had the minimum and maximum silt content, respectively. Chemical composition of Abay Wodehimado, Aliyas and Abay Wodeyamado sand sources, SiO2 + Al2O3 + Fe2O3, is testified pozzolana class F as per ASTM C-618 and the loss of ignition, MgO, Na2O, and K2O values meet the standard requirement. Accordingly, Kuye, 19.972 MPa, and Abay Wodeyamado, 28.957 MPa, resulted the lowest and highest compressive strength, respectively. It is concluded that sand found in Debre Markos Town and its surrounding contain silt and clay content and organic impurities that exceed the allowable limits and it resulted significant reduction in concrete strength. It is recommended that the concrete mix design in the city should always consider the strength reduction due to presence of these impurities and gradation to ensure that target strength of the resultant concrete is achieved.