<p>When dealing with silty soils, there is always a problem in construction because they have a low bearing capacity and can be easily deformed. The proposed research examines the possibility of waste brick kiln ash (WBKA) as a green stabilizing agent in reinforcing the mechanical and microstructural characteristics of silty soil. Laboratory experiments were done by combining WBKA to soil at 2.5, 5, 7.5, 10 and 12.5% by dry weight of soil. To determine the engineering behaviour of the stabilized soil, standard proctor compaction and unconfined compressive strength (UCS) tests were conducted. The samples were cured at 7, 28 and 180 days to analyse the effect of curing period on the strength development. The findings depict that the increase in the strength characteristics of silty soil by WBKA addition is substantial, and the dosage of 10% is determined as the optimum. The UCS of the soil at this dosage rose by a good weight of about 414 per cent with 180 days of curing in relation to untreated soil. The enhancement of the strength can be explained by the fact that the pozzolanic reaction of silica-rich WBKA with soil minerals results in the creation of cementitious compounds. The creation of N-A-S-H and C-A-S-H gels, leading to a stronger bonding of particles and a more compact soil structure is proven by microstructural studies based on Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). The results prove that WBKA may be the good and sustainable stabilizer of silty soils and contribute to the positive use of industrial waste materials.</p>