Analysis of 25 MPa quality concrete compressive strength with variations in sand zones

The need for aggregate in a concrete mixture is around 60-70% of the total weight of concrete, so the choice of aggregate can affect the quality of the concrete. Generally, when making concrete, coarse-graded sand is preferred over fine-graded sand because fine-graded sand has less strong adhesion between the grains. This condition could potentially lead to environmental degradation due to excessive excavation of coarse-graded sand. This research aims to analyze concrete mixtures in various sand zones to achieve a compressive strength of quality concrete of 25 MPa. The method used is laboratory experimental. The research results show that to achieve a concrete quality of 25 MPa, Water-Cement Ratio (WCR) values of 0.54, 0.53, 0.52, 0.50 are required; the amount of cement was 379.63 kg, 386.79 kg, 394.23 kg, 410 kg; and the percentage of sand to total aggregate is 39%, 39%, 38%, 37% for concrete mixtures using sand zones 1, 2, 3 and 4, respectively. The finer the sand gradation, the greater the amount of cement required, while the WCR value and percentage of sand to total aggregate are lower to achieve a concrete quality of 25 MPa.