Effect of Bottom Ash on the Properties of Subgrade Soil

The utilization of biodegradable substances for the improvement of poor soil has given better outcomes in the field of geotechnical engineering. They diminish the void proportion and thickness of absorbed water in the soil particles and boost the compaction of the subgrade. A decrease in moisture content causes an increase in shrinkage. This will bring about harm to the construction. In the recent years, manufacturers are claiming the increase in soil shear strength, decreasing in liquid limits, and swell index of the soil. Recent studies suggest that adding industry waste products like bottom ash or fly ash into the subgrade soil increases the California bearing ratio (CBR) values of the soil and decreases the swelling potential. In the present study, literature review and laboratory work were carried out on the mechanical stabilization of pavement subgrade mixed with industrial bottom ash (BA). In this study, bottom ash (BA) has been used as a filler material. An attempt has been made to evaluate the properties of soil, such as bearing capacity by replacing it with bottom ash (BA). Environmental scanning electron microscope (ESEM) study conducted to study shape and texture of particles of bottom ash and soil. Different proportions of bottom ash were mixed with locally available (well-graded sand) soil to assess their effect on the engineering properties of soil. Series of tests like California bearing ratio (CBR) of soil were carried out with different dosages of bottom ash with a varying range of 0 to 30% to compare the results. The addition of bottom ash up to a certain limit increased the CBR value by increasing its load bearing capacity and compressive strength of the soil. Using laboratory tests, it is concluded that bottom ash can be used as a filler material in road construction like embankments when they are properly compacted because their dry density is low as their lightweight particles.