Highway Research Record

Studies on Application of Coir Geo-Textiles on Pavements

Duration:June 2004
College of Engineering, Trivandrum (R, I)

Present Status and Progress
Laboratory tests were carried out to determine the standard strength, pull out stress and standard strain of different type of coir yarn. A road stretch was identified and finalized to lay the geotextiles to study the suitability of the coir geotextiles as a reinforcing layer to improve the subgrade characteristics. The manufacturing of coir geotextile is going on.

From the laboratory tests conducted on the coir yarn, it is found that due to wetting, the strength of coir yarn is reduced by 25-30% and strain is increased by 30-40% than the dry coir yarn. The treatment of coir yarn is done by immersing the coir yarn in Poly Vinyl Alcohol for about 10 minutes after which it is immersed in cement slurry and cured for 7 days. The treatment generally increases both strength and durability and reduces strain. The increase in strength due to the treatment is around 15-20% than the dry coir yarn. The strength of wet treated coir yarn gives less value than the treated coir yarn but is higher when compared to dry and wet coir yarn.
From the tests conducted on pull out resistance of different types of coir yarn, the results reveal that thin diameter coir yarn gives more pull out value than the thick diameter coir yarn. Generally wetting of coir yarn gives higher pull out value than other types of yarns. Treated coir yarn slightly increases pull out resistance than dry coir yarn. Wet treated coir yarn also gives more pull out value than the dry coir yarn.
It is seen that the average length of fibre in the yarn is around 10 to 15 cm. The studies show that the effect of fibre distribution per metre length of coir yarn is a significant parameter. From the cost analysis, it is seen that higher runnage coir yarn is more economical than lower runnage coir yarn.

Field trials are proposed to be carried out using coir Geotextiles.