UTILIZATION OF PALM KERNEL SHELL FOR FLY ASH GEOPOLYMER MORTAR IN INDONESIA

Abstract

Indonesia, as the world’s largest palm oil producer, generates millions of tons of palm kernel shell (PKS) waste annually, posing significant environmental challenges if inadequately managed. Concurrently, fly ash from coal-fired power plants offers a sustainable resource for geopolymer mortar production. This study explores the innovative use of activated carbon derived from PKS as an additive in fly ash-based geopolymer mortar to utilize both industrial by-products and enhance material performance. Activated carbon was produced from PKS via carbonization and physical activation, while geopolymer mortars were synthesized using sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) as alkaline activators with varying NaOH molarities (10 M, 12 M, and 14 M). The mortars’ mechanical strength, microstructural features, and chemical characteristics were comprehensively evaluated through compressive strength testing, SEM-EDX, XRD, BET, and FTIR analyses. Mortar activated with 12 M NaOH achieved the highest compressive strength (29.51 MPa) and exhibited superior microstructural integrity, characterized by a dense matrix, reduced porosity, enhanced durability, and strong chemical bonding. These results demonstrate the feasibility of incorporating abundant industrial and agricultural waste into sustainable construction materials, contributing to environmental impact mitigation, and advancing low-carbon building technologies.