GEOPOLYMER MORTAR PRODUCTION BASED KAOLIN AND LIME WITH W/S RATIO USING 6 M NAOH

Abstract

Geopolymer mortar is a mortar that uses an alternative binder to replace cement. The growing demand for concrete has led to increased cement production, contributing to global warming. Kaolin and lime are potential materials for geopolymer mortar, with kaolin mainly composed of silica and alumina, and lime containing a high level of calcium. This study explores the impact of using kaolin- and lime-based geopolymer mortar with different water-to-solid (W/S) ratios on its compressive strength and identifies the optimal ratio. The research employed an experimental approach, using W/S ratios as the key parameter. The test specimens were geopolymer mortar cubes made from kaolin and lime with a 6-molar NaOH solution, measuring 5 x 5 x 5 cm. A total of 63 samples were prepared, featuring 7 different W/S mix designs: 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, and 0.55. The findings indicate that the W/S ratio significantly affects the compressive strength, with higher ratios resulting in stronger mortar. The optimal W/S ratio identified in this study is 0.55, achieving the highest compressive strength of 4.79 MPa at 28 days compared to the other ratios.