Characterization of Precursor Materials for The Formulation of GEORAP (Geopolymer for Road Application) Utilizing Southeast Sulawesi Local Waste

Abstrak

Utilization of local industrial waste as geopolymer precursors offers a sustainable solution for road pavement materials while reducing environmental impact. This study aimed to characterize the physicochemical properties of three waste materials from Southeast Sulawesi—fly ash from Nii Tanasa Power Plant (FA), nickel slag from PT Antam Pomalaa (NS), and rice husk ash from Lambuya (RHA)—to evaluate their potential as geopolymer precursors. Characterization was performed using X-ray fluorescence (XRF), loss on ignition (LOI), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and Fourier transform infrared spectroscopy (FTIR). Results showed that FA was classified as Class C (CaO 27.12%) with a molar Si/Al ratio of 2.22, spherical morphology, and Si-O-T band at 940 cm−1. NS exhibited high MgO content (28.90%), angular morphology, and Si-O-T band at 918 cm−1, potentially forming N-M-A-S-H gel. RHA demonstrated high silica purity (SiO2 96.24%), porous structure, and Si-O-T band at 1072 cm−1. All materials complied with ASTM C618-23 LOI limit (<6%). Based on cross-validation between methods, a ternary formulation of FA:NS:RHA = 60:25:15 with a target Si/Al ratio of 2.0–2.5 is recommended for developing geopolymer for road application (GEORAP).

Kata kunci

• Fly Ash
• Nickel Slag
• geopolymer
• physicochemical characterization
• rice husk ash
• road pavement material