Tensile Strength and Morphological Properties of Chemically-Treated Composite Abaca-Coco Coir Twine and Rope as Natural Geotextile Materials

Abstract

The use of natural fibers has recently received attention due to their potential as sustainable, green alternatives to geosynthetics. This study investigates the morphological properties of raw and chemically-treated abaca and coconut coir fibers. Fibers were immersed in a 6% NaOH solution for 24 hours to remove surface impurities. Twines and ropes were fabricated using abaca fibers and coconut coir. Each abaca and coconut coir twine has a diameter of 5.0 ± 1.0 mm, while the composite abaca-coconut rope has an average thickness of 10.0 ± 1.0 mm. The fabrication adhered to the standards set by the Department of Public Works and Highways (DPWH) for bioengineering coconet applications, as specified in D.O. No. 29, Series of 2008. The resulting fibers, twines, and ropes were evaluated for tensile strength using ASTM D3822 for single fibers and ASTM D2256 for twines and ropes. Scanning Electron Microscopy (SEM) was used to analyze the morphological changes after treatment. The results showed significant improvements in the morphological properties of abaca and coconut coir fibers, particularly after alkaline treatment, compared with DPWH-standard coconut coir-based geotextile materials. Notable changes were observed, including increased surface roughness, enhanced fibrillation, and removal of surface impurities. These findings imply the potential of alkali-treated abaca and coconut coir fibers as durable, high-performance, and locally sourced natural geotextiles for bioengineering and soil stabilization.