CHEMICALLY STABILIZED FIBER OF OIL PALM EMPTY FRUIT BUNCH FOR SOIL STABILIZATION

Abstract

The exploration of oil palm empty fruit bunch (OPEFB) fiber as a construction material, especially in geotextile applications, is a growing area of interest. However, OPEFB fibers degrade rapidly, particularly in soil conditions, due to their natural composition. This study investigates the application of an alkaline solution, sodium hydroxide (NaOH), for enhancing the fiber strength and durability. OPEFB fibers, sourced from a palm oil mill in the Tanah Bumbu Regency, were treated via immersion in a 1N NaOH solution for 90 min. Subsequently, these treated fibers were embedded in soft soil and cured for 1, 7, 14, and 28 d under both open and closed conditions (that is, covered with plastic wrap). Tensile strength was assessed using specialized equipment designed for this purpose. Additionally, the fibers were blended with soil at a percentage of 7% based on dry weight, and compacted with 10% water content and a dry volume weight of 16 kN/m³. These samples were then tested for compressive strength, revealing a substantial improvement in the average tensile strength of fibers treated with NaOH at 288.22 MPa, which is 2.77 times greater than untreated fibers. Furthermore, the treated fibers exhibited enhanced durability, with tensile strength ranging between 160.2‒179.58 Mpa and 184.11‒222.2 MPa under closed and open conditions, respectively. Additionally, the compressive strength of the soil with treated fibers exceeded that of the soil with untreated fibers. Microscopic analysis revealed that the morphology of the treated fiber was denser and free of surface impurities, contributing to its improved performance.