Influence of randomly mixed coir fibres and fly ash on stabilization of clayey subgrade

This paper discusses the stabilization of clayey subgrade when mixed with coir fibres (CF) randomly and fly ash (FA). The tests were carried out on the locally available clay soil with different proportions of randomly mixed CF and FA. The CF and FA proportions used in the study are expressed in percentage by dry weight of soil. The CF and FA proportions used in the present study are 1%, 1.5% and 2% and 0%, 5%, 10%, 20% and 30% respectively. The tests results revealed that the clayey subgrade stabilized with FA resulted in improvement of strength and California bearing ratio (CBR). Further, it is observed that randomly mixed 1% CF and 20% FA mixture resulted in improvement of CBR of subgrade as compared to clay subgrade treated with 20% FA alone and this increase is noticed as 1.5 times. Overall, it is concluded that 20% FA + 1% CF resulted in improvement of subgrade in terms of CBR.