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CBR Behaviour of Soil Treated with Class ‘F’ Fly Ash

Prasanna P. Kulkarni


Disposal of fly ash available at thermal power stations is not only a serious national issue but also causes endanger to the mankind if not properly utilized and handled. The study aims at making effective utilization of Class ‘F’ fly ash by mixing with soil in suitable proportions and showcasing its usage to be adopted in subgrade as well as subbase components in pavement infrastructures. Silty sand was mixed with increasing percentages of Class ‘F’ fly ash ranging from 0–50% by dry weight of soil. Unsoaked and soaked California bearing ratio (CBR) tests were conducted in Geosynthetics Research and Testing Laboratory, IIT Bombay. A substantial increase in soaked CBR value of about 70.5% was observed on adding 30% of fly ash. The values of liquid limit, plastic limit and plasticity indices also were observed to be decreased on account of addition of fly ash. It was concluded that addition of Class ‘F’ fly ash to the soil, not only proves to be an economical solution in pavement infrastructures but also can be treated as an environmental friendly solution for its disposal in an effective manner.

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