Measurement of mechanical characteristics of fiber from a novel invasive weed: A comprehensive comparison with fibers from agricultural crops

With growing importance of green infrastructure, sustainable natural fibers such as coir and jute are extensively used for shallow depth embankment reinforcement. The motivation of the study is to investigate the reinforcing potential of an invasive weed species (water hyacinth) for subgrade reinforcement and juxtapose its reinforcing efficacy with that of the conventionally used coir and jute fibers. For such a comparison, a series of unconfined compression strength (UCS) tests was conducted on clayey silt reinforced with randomly distributed fibers extracted from the selected species. The results were used to study the influence of different fiber percentages, soil-fiber composite density and moisture content on the strength improvement factor (SIF) of the soil-fiber composite. Further, the test results were used to study the soil-fiber composite ductility using all three fibers. To explain the soil-fiber composite ductility, two new physical parameters has been identified. Among the three fibers tested, jute showcased the highest strength in majority of the tested conditions. However, coir and WH fibers are equally competent for increasing SIF at least by 50%. Among the tested soil-fiber composite, coir reinforced soil showcased highest ductility at the tested conditions, which is attributed to its high elongation at break. The post peak ductility of soil-fiber composite is dependent mainly on the fiber percentage and the compaction state. This is mainly governed by the development of fiber bridges in the shear band and also due to “lubrication” effect.