Sulphate corrosion occurs due to a chemical reaction between the hydration of cement, which is a concrete compound, and sulphate ions, resulting in deterioration in concrete. Pozzuolanas such as fly ash are used instead of cement to reduce or minimize damage caused by sulphate on concrete. This study uses fly ash tailings from Afsin Elbistan thermal power plant, which has a component close to cement instead of cement, which is one of the main components of concrete. Examples of different fineness obtained by grinding the fly ash (FA) in the ball mill for 0, 10 and 20 minutes were prepared with a FA substitution rate of 10%, creating examples of fly ash-added concrete. These examples were then exposed to a 10% and 5% additive sulphate solution and tested for compressive strength and ultrasonic pulse velocity measurement tests to investigate the effect of concrete samples on sulphate resistance. According to the results obtained, the compressive strength values of concrete samples exposed to a solution of 5% and 10% sulphate have been observed, depending on the fly ash grinding time. It has been found that the concrete samples added have reduced compressive strength by increasing the amount of sulphate solution and have a higher compressive strength value than the reference sample. However, weight losses have been reduced as the grinding time increases. It has also been determined that ultrasonic pulse velocity values have increased as a result of the increase in the fineness of the grinding and the fineness of the flying ash.