Potential of Bentonite-lime-mix Modified with Phosphogypsum and Reinforced with Sisal Fibres

Abstract

The paper presents the potential of bentonite-limephosphogypsum mix reinforced with sisal fibre in effectively reducing the pavement thickness in an extremely problematic sub-soil condition intended for road construction. In view of which, compaction, unconfined compressive strength and California bearing ratio tests were conducted. The content of lime, phosphogypsum and sisal fibre was varied from 0 to 10%, 0 to 10% and 0 to 2% respectively. The specimens were prepared at their respective optimum moisture content and maximum dry unit weight for conducting the unconfined compressive strength and bearing ratio tests and were cured for 3 to 28 days. The results of this study reveal that the unconfined compressive strength and bearing ratio of the bentonite-lime-phosphogypsum mix increased with the increase in curing period. Addition of sisal fibres to the bentonite-limephosphogypsum mix changes the behaviour of the composite from brittle to ductile in the post peak region. Scanning electron micrographs and energy-dispersive X-ray analysis confirms the improvement in unconfined compressive strength and bearing ratio. The improved behaviour of the composite indicates that the sisal fibres have the potential for use in road pavements.