The Pozzolanic Effect of Fly Ash on the California Bearing Ratio Behavior of Black Cotton Soil

Thermal power stations that use pulverized coal as fuel generate large quantities of fly ash, resulting in environmental and disposal problems. Increasing demand for power leads to a greater use of coal and hence a further increase in the quantity of fly ash. These problems can be solved if the fly ash is put to use in an environmentally friendly way. Among the various uses for fly ash, the most massive and effective use is in geotechnical engineering applications. The study of fly ash and its interaction with soil is a must towards this goal. In the present investigation, an attempt has been made to study the engineering properties of fly ash—black cotton (BC) soil mixes with special reference to their use as sub-base materials in pavement construction. The study aims to understand the effect of fly ash on the California bearing ratio (CBR) of BC soil. The CBR variation is observed to depend upon the particle size distribution and pozzolanic nature of fly ash. The study indicates that addition of fly ash increases the CBR of BC soil significantly