The effect of natural sand composition on concrete strength

Natural sands show a variety of mineralogic compositions and chemical characteristics; when sand is used in concrete aggregate, these properties may result in different concrete strengths. However, there is little data about the effects of different sand aggregates on concrete strength. In this work we highlight some mechanical aspects regarding the use of sand from different origins such as concrete aggregate. The sand samples were first tested to determine their mineralogic and chemical characteristics and their aggregate properties. Then, concrete test samples were prepared using these aggregates, and the properties of the fresh and hardened concrete were determined. The results show that although all the samples were found to be suitable for use as fine aggregate in high-strength concrete production, natural sands that contained smectite-type clays have poor aggregate quality compared with other sands. Conversely, the chemical composition of the natural sand samples, especially the Na2O content, is important for predicting the strength properties of hardened concrete.