In this study, Portland cement (PC 42,5) replaced with Chrome Magnesit brick dust as a ratio of its weight of %0, %5, %10, %15, %20, and %25. By this procedure, six different mixtures were prepared and effect of cement was investigated on the starting and finishing time of the setting. As a result, while the mixture with 5% Chrome Magnesit brick dust decreases the starting and finishing setting time in small amount with, the increasing amount of the Chrome Magnesit increases the starting and finishing setting time. Also, by using Fuzzy Logic method, prediction model was constituted based on the quantity of Chrome Magnesit brick dust to predict the starting and finishing time of the setting for cement which could not be determined with experimental. It was showed that the prediction model could be used to predict the starting and finishing time of the setting for cement based on the quantity of brick dust.