Effect of chemically treated coir fibres on the strength characteristics of clay

The effect of chemically treated coir fibres on the strength characteristics of clayis presented in this study. A series of consolidated undrained test were performed on soil reinforced with untreated, sodium hydroxide treated and potassium permanganate treated fibres. The coir fibre content was varied from 0.25% to 1.5%. The results indicated that the optimum moisture content of clay reinforced with untreated/treated coir fibres increases with the increase in fibre content. The optimum moisture content of clay reinforced with treated coir fibres was less in comparison to untreated coir fibres. KMnO₄ treated coir fibre absorbs slightly less water in comparison to NaOH treated coir fibres in clay. The dry unit weight of clay reinforced with untreated/treated coir fibres decreases with the increase in fibre content. The dry unit weight of clay reinforced with treated coir fibres was higher in comparison to untreated coir fibres. Reinforcing clay with KMnO₄ treated coir fibre results in higher dry unit weight in comparison to NaOH treated coir fibres. The peak deviator stress of clay reinforced with coir fibres can be significantly improved by treatment with NaOH and KMnO₄. With the increase in coir fibre content (0.25%-1.5%) in clay, there was an increase in the peak deviator stress. The shear strength parameters were found to increase with increase in coir fibre content (0.25%-1.5%) in clay. The addition of KMnO₄ treated fibres to the clay results in a higher value of peak deviator stress and shear strength parameters. The hyperbolic model can be used for predicting the stressstrain response of unreinforced and reinforced clay with appropriate selection of model parameters. The clay reinforced with untreated/treated coir fibres has shown improved strength characteristics, it can be used for short term stability problems.