Field Evaluation of Coir Geotextile Reinforced Subgrade for Low Volume Pavements

ABSTRACT

This investigative study focuses on the response of full scale coir reinforced low volume roads when subjected to static loading. The test track of 1.736 km consists of a control section and eight reinforced sections including two types of coir geotextiles and subbase with varying thickness. An assessment of the general behavior of coir geotextile-reinforced sections, to static plate load tests, California Bearing Ratio tests, geogauge and dynamic cone penetration tests is done for evaluation. The study summarizes the results of the executed tests on the reinforced test track in comparison to the unreinforced one. The results reveal that the geotextile with higher apparent opening size is not as good as that of the finer mesh geotextile. A maximum of 112% improvement in the elastic modulus of subgrade is achieved by using a woven coir geotextile of 740 g/m² mass per unit area whereas 70% increment is attained while using an alternate geotextile of 365 g/m² mass per unit area. The elastic modulus values are determined from the various field tests and the overall damage analysis is carried out using KENPAVE software. From the analysis, it is noted that an appreciable decrease in the aggregate layer thickness is achieved by using coir geotextile as reinforcement. Use of coir geotextiles in pavements as a reinforcement can therefore help in reducing the demand and consumption of fast-depleting natural resources.

摘要

本研究的重点是全尺度椰壳加固的低体积公路在静载作用下的响应. 全长1.736公里的测试轨道由一个控制段和八个加固段组成，包括两种不同厚度的椰壳土工织物和地基. 对椰壳土工织物加固截面的一般性能进行了评价，包括静板荷载试验、加利福尼亚承重比试验、测径试验和动力锥贯入试验. 研究总结了加固试验轨道与未加固试验轨道的对比试验结果. 结果表明，具有较高表观开孔尺寸的土工布不如细目土工布. 使用单位面积质量为740 g/m2的土工织物，地基弹性模量最多可提高112%，而使用单位面积质量为365 g/m2的土工织物，地基弹性模量最多可提高70%. 通过各种现场试验确定弹性模量值，并使用KENPAVE软件进行整体损伤分析. 从分析中可以看出，采用椰壳土工织物作为加固材料，骨料层厚度明显减小. 因此，在人行道上使用椰壳土工布作为加固材料，有助于减少对快速消耗的自然资源的需求和消耗.

KEYWORDS:

• Coir geotextile
• Reinforcement
• Subgrade
• Elastic Modulus
• KENLAYER
• low Volume Roads

Acknowledgement

The study has been conducted to analyse the coir geotextile reinforced roads laid under the Prime Minister Gram Sadak Yojana (PMGSY) and Bharat Nirman Programmes of Tamil Nadu. The authors gratefully acknowledge the research funding from Coir Board, Ministry of Micro, Small and Medium Enterprises (MSME), Government of India for the project entitled, “Pavement Performance Studies on Coir Geotextile Reinforced Rural Roads in Tamil Nadu.”