Abstract

ceeded, may cause a cracks. One of the modern methods used to estimate the stability of the cement size (expansion) is the autoclave method, this study aim to estimate the stability of the cement and this will gives an indication of the late expansion. The statistical program “Statistica” were used in the analysis of the factors affecting the results of autoclave test these factors were (CaO, SO3 , MgO, Al2 O3 , Fe2 O3 , free lime, LOI, IR, LSF). The linear regression method was used and the study were done in two ways individually and again in groups. The multiple linear regression was found to be very appropriate for predicting the autoclave expansion of Portland cement. On the other hand there is no significant variance in the value of correlation coefficient when studying the factors individually or in groups, so, it is preferable to use models with individual factors for facilitate of research.