EFFECT OF LIME SUBSTITUTION ON KAOLIN-BASED GEOPOLYMER MORTAR WITH 15 MOLAR NaOH MODIFICATION

Abstract

Infrastructure development continues to encourage equitable growth and improve the economy. With the increasing need for infrastructure development, it is necessary to explore alternative materials in mortar mixes, such as geopolymer technology. Geopolymer mortar is a type of mortar that completely replaces cement as a binder with pozzolanic materials. This research aims to analyze the effect of lime substitution on the compressive strength and porosity of kaolin-based geopolymer mortar at 15 Molar NaOH concentration. This study used an experimental method using geopolymer mortar test specimens with dimensions of 5 × 5 × 5 cm with treatment at room temperature. A total of seven mix design variations were tested, with lime substitution of 5%, 10%, 15%, 20%, 25%, and 30%. The results showed that the highest compressive strength and lowest porosity values were achieved at 28 days of age. The optimum composition was found at 10% lime substitution, resulting in a compressive strength of 2.9 MPa and porosity of 14.89%. This shows that as the mortar ages, its compressive strength increases while its porosity decreases. In addition, lime substitution significantly affected the mechanical properties of the geopolymer mortar.