PEMANFAATAN ABU TERBANG (FLY ASH) UNTUK PEMBUATAN BETON GEOPOLIMER PADA KONDISI DAERAH AGRESIF DENGAN MOLARITAS 12 MOLAR

Abstract

A kind of concrete called geopolymer concrete is one that that entirely eliminates the use of cement as a binder, replacing it with other elements like rice husk ash, fly ash, and coconut husk ash, and others. In this study, fly ash is employed. The fly ash and its alkaline activators involve 12 molar sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃), with heat curing treatment at an overnight temperature of 100°C. This research is conducted to determine the compressive strength of geopolymers concrete under normal conditions at the age of 28 days., immersion in a high- acidic mixture with a 2.0–3.0 pH, and burial in peat soil with a pH of 4.0-5.0 at the age of 56 days. The highest compressive strength is observed in the geopolymer concrete under normal conditions, reaching 68.41 MPa. Subsequently, the compressive strength of the concrete buried in peat soil with a pH of 4.0–5.0 is 56.34 MPa. The concrete submerged in very acidic solutions (pH 2.0–3.0) had the lowest compressive strength, at 52.52 MPa. Consequently, it may be said that the corrosive nature of acids causes a decrease in the compressive strength of geopolymer concrete in acidic environments.
Keywords: Fly ash, 15 molar, geopolymer, acid solution, peat soil, compressive strength.