The effect of fly ash grain size on CBR and strength in high plasticity clayey soil stabilization

Soil stabilization can be divided into two as deep and surface stabilization. One of the surface stabilization application is chemical stabilization. In this study, which aims to examine the effect of fineness on chemical soil stabilization, the engineering properties of a high plasticity clayey soil were improved by using fly ash. Fly ash was added to the soil separately as it was taken from the thermal power plant and in a fine (grinded) form. CBR and strength data were investigated by adding fly ash to the soil at the rates of 5%, 10%, 15%, 20%, 25%, 30%, both raw and grinded. Curing times were determined as 7 and 28 days for the unconfined compressive strength tests during the study period. As a result of this study, in which consistency limits, compaction, CBR and unconfined compressive strength tests were carried out, it was determined that the use of fly ash by thinning in soil stabilization had a limited effect on compaction parameters, was relatively effective on consistency limits, and resulted in very high increases in CBR and strength values. In the light of these results, it was concluded that stabilization studies can be carried out on a high plasticity clayey soil with the addition of finer fly ash, which can reach higher CBR and strength data.