Title: Experimental studies on coir geotextile reinforced low volume rural roads

Abstract

This paper proposes the practical implementation of improvement of weak subgrade soil by using coir geotextile. The test track is subjected to various tests to study the improvement in structural behaviour of the reinforced pavement. The total length of the road was divided into three sections. This was done to analyse the performance of coir reinforced pavements with sections of different thickness and types of coir geotextiles. Coir geotextiles with mass density 740 gsm (designated as CGT1) and 365 gsm (designated as CGT2) of widths 6 m and 8 m were used. The study explores the improvement in elastic modulus that could be attained by the subgrade reinforced with coir geotextiles through field experiments like geogauge and static plate load tests. The culmination of this work is the preparation of design guidelines for coir geotextile reinforced low volume roads. Hence baseline design inputs that are obtained from the above mentioned tests were used for the numerical analysis using KENPAVE software. The data reveal that the elastic modulus of the subgrade has multiplied appreciably when reinforced with coir geotextile, which would help in increasing the service life of the pavement. The same has been reflected in the distress survey results also. The improvement attained is 1.41 and 1.25 times of the elastic modulus of the parent soil, with coir geotextile of mass per unit are 740gsm and 365gsm, respectively. The modified subgrade elastic modulus has been inputted in the KENPAVE software and analysed in order to prepare a design chart for coir geotextile reinforced low volume roads.