The Effect of Using Volcanic Sand from Mount Soputan as a Substitute for Fine Aggregate in the Production of Bricks

Abstract

Concrete blocks are a type of building unit shaped like bricks, made from a primary mix of Portland cement, water, and fine aggregate, used for wall construction. The purpose of this study is to assess the effect of using volcanic sand from Mount Soputan as a substitute for fine aggregate on the water absorption and compressive strength of concrete blocks. Based on absorption tests at 28 days, high water absorption values were observed during immersion periods of 1, 5, 10, 30, 60 minutes, and 24 hours. The highest absorption value was found in normal concrete blocks at 1.30%, and with 20% volcanic sand addition at 1.16%. High water absorption is due to the larger pores in these concrete blocks compared to other variations. Conversely, the lowest water absorption was observed in the 30% volcanic sand variation at 0.80% and the 40% volcanic sand variation at 0.75%. According to the compressive strength test results, the highest compressive strength was found in the 40% volcanic sand mixture at 28 days, with a value of 250.95 kg/cm². Meanwhile, the lowest 28-day compressive strength among all mixtures was found in the normal concrete blocks, with a value of 164.50 kg/cm². Among the volcanic sand mixtures, the lowest 28-day compressive strength was found in the 20% volcanic sand variation, with a value of 176.82 kg/cm². Therefore, it can be concluded that the use of volcanic sand as a partial substitute for fine aggregate affects the compressive strength of concrete blocks, with the 40% substitution level giving the best performance in this study.Therefore, it can be concluded that the use of volcanic sand in the production of concrete blocks significantly affects their compressive strength