Limits fixed in Codes for the chemical characteristics of cements have been established with semi-empirical methods, given the complexity of influencing phenomena, without correspondence between these values and the physico-chemical or mechanical properties as durability or strength. Knowledge of statistical distribution models allows to fix limits of acceptation or rejection, with criteria of frequencies, and dependence relationships among them. In order to propose distribution models for the percentage of Ignition Loss, Insoluble Residuum and SO3, the values of the variables on 255 samples analysed at the Instituto E. Torroja during 10 years, have been studied. Dependences among variables, defined by the correlation coefficients, have been studied as well. Sample values have been grouped in equally probable intervals and goodness of fit with Normal, Gamma and Log-Normal distributions was done by means of test X2. Finally, goodness of fit and agreement between upper fractals and maxima values in samples let us propose distribution models for each variable.