PENGARUH ABU SEKAM PADI SEBAGAI SUBSTITUSI ABU TERBANG TERHADAP SIFAT MEKANIK BETON GEOPOLIMER

Abstract

This study investigates the effect of rice husk ash as a substitute for fly ash on the mechanical properties of geopolymer concrete. Fly ash, used as a binder in geopolymer concrete, was replaced with rice husk ash at varying percentages of 0%, 4%, 8%, and 12% by the weight of the precursor. Tests were conducted to evaluate the impact of this substitution on the workability, setting time, compressive strength, modulus of elasticity, and splitting tensile strength of geopolymer concrete. The results showed that increasing the percentage of rice husk ash reduced the workability and accelerated the initial and final setting times of the geopolymer paste. Substitution with up to 8% rice husk ash improved the compressive strength, modulus of elasticity, and splitting tensile strength of the concrete. The optimum values were obtained at 8% substitution, with a compressive strength of 35.98 MPa, a modulus of elasticity of 18,075.66 MPa, and a splitting tensile strength of 2.28 MPa. This study demonstrates that rice husk ash can be effectively used as a substitute material to enhance the mechanical properties of geopolymer concrete, while also reducing dependency on fly ash and the environmental impact caused by cement production.