The potential to damage synthetic graphite is high during the pyrolysis of pitch/coke composite material in processing of carbon/carbon components. Exact modeling of heating patterns could optimize the preparation conditions in order to obtain high quality products. A capillary-cell model was built to evaluate the internal pressure resulting from volatile matter in green carbon blocks during carbonization. The theoretical model for heating patterns was proposed by considering the influence of heating rates on the internal pressure and the thermal stress during the heat-treatment procedure. The results showed that the theoretical heating rates were mainly controlled by mass transfer in the range 467-850 K and by heat transfer in other temperature ranges. The values calculated by the developed model were compared with the industrial results, and the validity of the proposed method for the prediction of heating patterns is evaluated.