Fly Ash is a type of industrial trash that is produced as a by-product of a thermal power plant. It's a nonreactive, inert particle that can float in the air for a few seconds to several months. There have been multiple researches conducted on the influence of fly ash on pavement construction. The objective of this study is to investigate how the load bearing capacity of soil changes when differing percentages of fly ash are added to the soil. The data was obtained from NTPC Badarpur. If the available soil is good in nature, we can easily create pavement; however, if the available soil is poor in nature, we can use Instead of an expensive route, fly ash can be considered as an alternative for improving soil condition. To begin, soil parameters were considered using different tests of soils, and then Atterberg Limits were estimated. On soil, a MPT (Modified Proctor Test) was used to determine the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD). A sample is compacted at OMC for the CBR test, and the results are assessed in percentages of 8%, 10%, 12%, and 13% based on the dry weight of the soil. To determine the load bearing capability of soil, CBR test is used in both wet and dry situations so that the pavement can endure even the worst conditions and the thickness of the pavement can be determined.