Long-Term Strength Studies on Natural Fibre Composite (N-F-C) Sheets for Use as Separator in Flexible Pavements in Terms of CBR Values

Abstract

Coir fibre–polymer composite being economical and ecofriendly, can be considered as a best alternative for the geosynthetic composite. The use of coir fibre–polymer composites can be extended to ground improvement and can be used as a separator in flexible pavement. This paper deals with the long-term performance in terms of strength criteria of natural fibre composite sheets for use as separator in flexible pavements. The study was confined to three types of composites: coir fibre latex composite sheet, woven coir mat and woven coir mat latex composite sheet. In the study the strength characteristics were studied using the California Bearing Ratio (CBR) test method. The tests were conducted at an interval of one month for a period of four months to study the time dependent strength variation on natural fibre composites. A system of soil, aggregate and composite is used for CBR test. The soaked CBR values for various composites developed are studied and compared for their strength characteristics. Several results show that with time the residual strength increases initially and converges to a certain value, after which the rate of deterioration decreases at a small value. Among the three types of composites, woven coir mat latex composite is expected to give better results in terms of strength characteristics.