Abstract
The present study aims at construction of expert computer model for forecast of compressive strength of the Portland cement. This model is achieved by chemical data input through interface designed by matlab program. This is followed by calculation of the content of phases; namely, C3S , C2S , C3A and C4AF. Later on , connection with fuzzy logic interface were made. The formentioned phases represent the input to the fuzzy logic interface through the condition rules IF-THEN. After defuzzification, the values of cement compressive strength appeared on the interface. The evaluations were made through calculation of square difference of the results of fuzzy logic ( present study) and statistical methods.