The behavior of expansive soil, also referred to as “black cotton soil,” has been the focus of extensive research by geotechnical engineers, who have also applied effective management techniques. The goal of the current study is to clarify the effectiveness of alccofine-1203 and dry leaf ash (DLA) (natural ash) powder in improving the characteristics of soil and in enhancing high swell and shrink, and low bearing capacity soil, which has advantages for builders. The effects of alccofine-1203 (3, 6, 9, and 12%) and dry leaf ash (2.5, 5.0, 7.5, and 10%) on the Atterberg limits, OMC, UCS, MDD, SEM, XRD, and other crucial soil characteristics have been calculated using an experimental program. Separate amounts of each admixture were mixed into the porous soil. The addition of the designated admixtures was found to significantly reduce the expansive soil's swelling behavior, plasticity index IP, liquid limit WL, and plasticity index OMC. UCS is gradually increased from 46.4 kPa to983 kPa at 56 days with the combined effect of 9% alccofine + 7.5% DLA reacted with soil is played a vital role when compared to the remaining combination of admixtures. Calcium silicate hydrate (C-S–H), calcium aluminate hydrates (C-A-H), and other cementitious compounds that are visible in SEM and XRD studies were ultimately lead to the increase in strength. Thus, the results showed that the addition of 9% alccofine and 7.5% DLA demonstrated an essential improver and prove that by adding the admixture is a potential stabilizer, and also, the problematic soil is transformed into the best soil.