Effect of Adding Sand on Cement Mixtures: An Experimental Investigation of Compressive Strength Using Portland Cement and Nalut Sand

Abstract

This study aims to evaluate the effect of adding different proportions of sand on the compressive strength of cementitious mixes. Portland cement and sand sourced from Nalut were used, and compressive strength tests were conducted in accordance with the international standard ASTM C109. Cubic specimens were prepared and tested at curing ages of 7 and 28 days.  The specimens were produced with varying sand-to-cement ratios. The results showed an inverse relationship between sand content and compressive strength, whereas increasing the cement content led to a noticeable improvement in compressive strength. One specimen yielded an anomalous and illogical result during testing; it was retested successfully, highlighting the importance of quality control in experimental work.  The results were graphically represented and analyzed to determine the optimum proportions for engineering applications. The study recommends the use of specific optimal sand–cement mixing ratios that balance quality and cost to achieve the best engineering performance. Furthermore, it opens prospects for the utilization of local materials in construction projects in accordance with precise economic and technical standards.