Utilization of Bottom Ash and Sawdust Waste as a Substitute for Fine Aggregate in Concrete Mix

Concrete is a split mixture, sand, cement, water, and additives. The concrete to be designed is made of a mixture of cement with bottom ash + sawdust, split, sand, and water. The purpose of this study was to determine the effect of using bottom ash + sawdust and the ratio between bottom ash + sawdust and fine aggregate. In this study using variations of 0%BA+SK: 100%AH; 5%BA+SK: 95%AH; 10%BA+SK: 90%AH; 15%BA+SK: 85%AH; 20%BA+SK: 80%AH; 25%BA+SK: 75%AH. The results of testing the compressive strength of concrete at the age of 28 days for 0%BA+SK: 100%AH; 5%BA+SK: 95%AH; 10%BA+SK: 90%AH and 15%BA+SK: 85%AH obtained 262.52 kg/cm2; 253.63 kg/cm2; 242.67 kg/cm2; and 235.11 kg/cm2 meet the requirements for concrete quality of 225 kg/cm2. For a mixture of 20%BA+SK: 80%AH, 25%BA+SK: 75%AH at the age of 28 days obtained 203.70 kg/cm2 and 197.93 kg/cm2 and does not meet the concrete quality requirements of 225 kg/cm2. Concrete mixture using 15%BA+SK: 85%AH is the best concrete mixture, and the concrete compressive strength is 235.11 kg/cm2. The more the use of bottom ash and sawdust into the concrete mixture, the compressive strength of the concrete will decrease.