Long-Term Performance of Rural Roads Reinforced with Coir Geotextile – A Field Study

Abstract

India has one of the largest road networks in the world, aggregating to about 56 lakh km at present. At sites with inadequate CBR, problems of excessive rutting are very common. In order to overcome this ground improvement techniques such as inclusion of coir geotextile is a good option. Coir geotextiles are manufactured with coir fibers, extracted from the husk of coconut, and are more durable than other natural fibers due to high lignin content. Construction of pavements strengthened with coir geotextiles makes it cost-effective and eco-friendly. In this paper, the results of the performance study conducted on five coir geotextile reinforced and unreinforced roads in different parts of Kerala, after three to 6 years of construction are reported. Coir geotextile had been placed in between subgrade and sub base. The performance was evaluated by conducting Benkelman Beam Deflection (BBD), Field CBR and Dynamic Cone Penetration (DCP) test on reinforced and unreinforced roads. A reduction in characteristic deflection thereby decrease in bituminous Macadam overlay, decrease in DCP Index and improvement in in-situ CBR values ranging from 22% to 178% were obtained for roads on all types of soil. A correlation was also developed between field CBR and field DCPI.

Keywords

• subgrade
• coir geotextile
• characteristic deflection
• overlay
• dynamic cone penetration index
• field cbr