Study of Making Concrete Block Using Gawan River Sand and Coal Waste (Bottom Ash) with Portland Cement Padang Viewed from the Perspective of Strength and Production Costs
Authors: Nur Sahid Co. Prof. Muhammad , Santoso Bayu Aji 
Published: August 2024

Data from the DPUPR of Sragen district, the price of Merapi sand in 2020 is IDR 1,590,000 then in 2021 the price of Merapi sand is IDR 1,680,000. The increase in the material price of Merapi sand in Sragen Regency has forced the brick maker UD. Cerah, whose address is in Dayu village, Jurang Jero sub-district, Karangmalang subdistrict, Sragen district, is again racking her brains to set a selling price for the bricks to avoid losses. The making of the brick itself cannot be separated from the costs incurred for purchasing raw materials, purchasing equipment for making bricks, and labor costs. So with the high price of Merapi sand material, it requires that the brick maker, UD. Sunny innovates by replacing the cheaper sand material. In this study using experimental methods for making bricks, using the full costing method for calculating production costs and using the depreciation method to obtain the annual depreciation load for brick machines. Based on research on the characteristics of fine aggregate river sand from Ngipang village, Gawan subdistrict, Tanon sub-district, Sragen district, the results of testing for silt content, testing for organic matter content, testing for specific gravity and water absorption, gradation testing met the requirements while testing for saturated surface dry (SSD) did not meet the requirements. Then research on the characteristics of fine aggregate from coal waste (bottom ash) obtained the results of testing for mud content, testing for organic matter content, testing for gradation that met the requirements while testing for specific gravity and water absorption, testing for saturated surface dry (SSD) did not meet the requirements. Based on the research on the compressive strength test of the bricks, it was found that the compressive strength of the bricks from river sand, Ngipang village, Gawan sub-district, Tanon sub-district, Sragen district was greater than the compressive strength of the bricks from coal waste (bottom ash), the maximum average compressive strength value of bricks from river sand in the village Ngiang, Gawan sub-district, Tanon sub-district, Sragen district obtained a value of 6.51 MPa on the 1PC : 5PS FAS mixture variation of 0.5, while the maximum compressive strength value of bricks made from coal waste (bottom ash) obtained a value of 5.10 MPa on the variation mix 1PC : 5BA FAS 0.6. Based on research on the production costs of making bricks, it was found that the production costs of making 1 m3 of river sand bricks in Ngipang village, Gawan sub-district, Tanon sub-district, Sragen district were greater than the production costs of making 1 m 3 of coal waste (bottom ash) bricks, the production costs of 1 m3 river sand bricks in Ngipang village, village Gawan, Tanon sub-district, Sragen district, the highest is in the mix variation of 1PC: 5PS FAS 0.6 with the production cost of IDR 962,237.49, while the largest 1 m3 coal waste (bottom ash) brick production cost is in the 1PC mix variation: 5BA FAS 0.6 with a production cost of IDR 659,285.51.