Effective utilization of natural fibres (coir and jute) for sustainable low-volume rural road construction – A critical review

Abstract

• Various treatment techniques for improving the strength and durability of natural fibres. • Correlations between physical and mechanical properties of coir and jute geotextiles. • Comprehensive laboratory and field studies pertaining to low-volume rural roads. • Efficacy of the natural geotextiles in enhancing the performance of low-volume rural roads​. Geo-reinforcement is one of the most important utilities whose primary function is to mechanically enhance the strength of soil specifically engineered for the construction of geo-structures. Utilizing polymer-based geosynthetic reinforcement for various applications in pavements has been successfully used for the past few decades. However, with the growing awareness towards the environment and climate change, there is a constant lookout for energy-efficient and sustainable reinforcing materials for road construction. Lignocellulosic fibres are sustainable and have the potential to replace synthetic reinforcing materials, especially for low-volume rural road construction (expected commercial vehicles less than 450 per day) wherein traditional ground improvement techniques are considered to be expensive. Extensive studies have focused on the enhancement of mechanical properties of subgrade by the inclusion of natural reinforcing materials based on laboratory and field studies without comprehensively understanding the problems associated with the durability and field compatibility in low-volume roads. Lack of clear understanding of these lignocellulosic fibres and the fibre-based geotextiles resulted in the reluctance in the material usage in most applications. An extensive review of the existing studies from the last 30 years was used to obtain a relationship between the physical, biochemical and mechanical characteristics of the lignocellulosic fibres to efficiently utilize them as reinforcing materials. Further, the various treatment techniques required to enhance the strength, stiffness, and durability of these fibres are critically examined. In addition to a complete understanding of the properties and treatment techniques for lignocellulosic fibres, the factors affecting the mechanical performance of coir (CGT) and jute (JGT) fibres-based geotextiles have been analyzed using regression techniques to efficiently utilize them as a reinforcing material in low-volume rural road construction. Finally, the increase in soil properties due to the presence of CGT and JGT is examined using extensive laboratory and field investigations/ case studies, thereby mitigating rutting, cracking, differential settlement, and other major failures in the flexible pavement. Based on this study, the scope for future research is also outlined.