The significant part of the electrical power over the world is produced in coal-firing thermal plants. Annually producing fly ash at thermal electrical power plants are about 48 million tons in the USA, 10 million tons in the UK, 15 million tons in Turkey. As the other industrial wastes, it leads to stocking and environmental problems. Only 10% of the total amount can be utilized in the construction industry in the US while remaining 90% have to be stocked in ash dams. In order to increase its impact on the environment utilization opportunities are being searched. Because of the low-cost availability and pozzolanic properties, the fly ash is used in cement industry, road construction and geotechnical practice. In this experimental study, shear strength and deformation properties fly ash added silty clay have been investigated.