Effect of Coir Fiber Reinforcement on Properties of Metakaolin-Based Geopolymer Composite

This study explored the use of coir fibers extracted from coconut husks, an agro-waste material that constitutes sanitation and environmental pollution problems, as a reinforcing element in the production of metakaolin-based geopolymer composites with improved properties. A series of sample formulations were produced with varying coir fiber content (0.5, 1.0, 1.5, and 2.0 percent weight of metakaolin powder). The investigation was conducted using a 10 M NaOH alkaline solution with a 0.24 NaOH:Na2SiO3 mass ratio. Samples were cured for 28 days and tested for bulk density, ultrasonic pulse velocity (UPV), and compressive and flexural strength. Microstructural examinations such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) were also performed on samples. Compressive strength values up to 21.25 N/mm(2) at 0.5% fiber content and flexural strength values up to 10.39 N/mm(2) at 1% fiber content were achieved in this study. The results obtained showed a decreasing bulk density of geopolymer samples (2113 kg/m(3) to 2045 kg/m(3)) with increasing coir fiber content. The geopolymer samples had UPV values varying from 2315 m/s to 2717 m/s. Coir fiber with 0.5-1.0% fiber content can be incorporated into metakaolin-based geopolymers to produce eco-friendly composite materials with improved mechanical properties for sustainable development.

Automated summary

This study investigated the use of coir fibers extracted from coconut husks as a reinforcing element in the production of metakaolin-based geopolymer composites. The results showed improved mechanical properties in the composites with varying coir fiber content, indicating the potential for eco-friendly composite materials for sustainable development.