Modelling the statistical fatigue behavior, based on fatigue test results is still a challenge for researchers and engineers. The model proposed by Castillo et al. is one alternative to describe this phenomenon, which is based on a three-parameter Weibull Distribution whose parameters should be estimated. There are several methods to determine these parameters, however there is no consensus about which is the most appropriate. In this article, a general formulation of the probability weighted moments of the Weibull Distribution is presented in order to estimate the parameters mentioned above. Finally, an application with experimental data from concrete specimens and simulated data is presented.