Water Retention and Desiccation Potential of Lignocellulose-Based Fiber-Reinforced Soil

This paper investigates the effects of three different lignocellulose fibers [jute, coir, and water hyacinth (WH)] on the soil water retention curve (SWRC) and desiccation potential of compacted clayey silt. Samples of compacted clayey silt mixed with an amount of discrete natural fibers were exposed to the natural environment and controlled events of 15 wetting/drying cycles for 105 days. Matric suction and moisture content of near-surface soil were monitored along with allied surface crack formation, quantified by the crack intensity factor (CIF). Adding lignocellulose fibers moderately increased the water retention capacity of the soil but had no significant effect on the rate of desaturation. The presence of fibers could reduce CIF effectively, by at least half the amount compared with bare soil. Among the fibers tested, coir provided the most significant resistance against desiccation cracking due to its comparatively higher lignin content and multifilament nature, which increase the fiber ductility and surface coarseness, both of which are favorable to resisting crack formation. The shape of the CIF-suction relation of selected soils mirrors that of the SWRC and may be represented by a simple modified van Genuchten fitting approach.