Utilization of Fly Ash and Bottom Ash Waste of PLTU Jeranjang on Geopolymer Paving

Abstract

Abstract Waste is produced as fly ash and bottom ash from coal-fired power stations. PLTU in West Nusa Tenggara uses 13,000 tons of coal in one month, so it can be estimated that Fly Ash waste will be produced around 1,950-2,210 tons. Geopolymer concrete utilizes fly ash as an adhesive to replace Portland cement. Fly ash is used to make geopolymer concrete, which is created by polymerization reactions caused by alkali-aluminosilicate reactions that result in materials with strong structures. In this study, the ratio of the composition of the weight ratio of paste (fly ash and alkaline solution) with aggregate was 35:65. The aggregates used are sand and bottom ash. The test object is a prototype paving block with a specific dimension of 10cm x 21cm x 6cm. Mechanical testing using compressive strength and water absorption testing with a specimen life of 7, 14, 21, and 28 days. Testing of bottom ash and fly ash characteristics in the form of XRF testing. The XRF test results found that the bottom ash and fly ash of PLTU Jeranjang belonged to class F. The average test result of compressive strength at the age of 28 days for mix designs A, B, and C was 8.54 MPa, respectively; 10.29 MPa; and 16.10 MPa. Quality geopolymer paving can be applied to gardens and other interiors used. Another result of the absorption value of Mix design C of 8% shows the addition of fly ash can be utilized in place of some of the used cement in paving blocks that satisfy SNI 03-0691-1996 Quality C criteria.