Analisis Sifat Mekanik Dan Perubahan Mikrostruktur Mortar Geopolimer Berbasis GGBFS Dan Diatomite Akibat Paparan Suhu Tinggi

Abstract

Geopolymer concrete is an eco-friendly alternative to conventional concrete as it eliminates the use of Portland cement, which contributes significantly to CO₂ emissions. This study aims to analyze the effect of combining Diatomite and Ground Granulated Blast Furnace Slag (GGBFS) on the compressive strength and microstructure of geopolymer mortar after exposure to high temperatures of 1000°C for 4 hours. Cube specimens measuring 5×5×5 cm were prepared with Diatomite-GGBFS variations (D10G0–D5G5) and activator molarity (8 M, 10 M, 12 M, and 14 M), and cured for 7, 14, and 28 days. The results showed that higher GGBFS content and increased activator molarity significantly improved the compressive strength, especially at 14 M. Meanwhile, Diatomite contributed to better thermal resistance due to its insulating properties. The optimal performance was observed in the D5G5 mixture with 14 M, which showed the highest strength and best microstructural stability after heating. This study highlights the potential of using industrial and natural waste materials to develop sustainable and heat-resistant construction materials.