Abstract
This study was carried out to investigate the combined effect of MgO and SO3 content in cement on soundness of the cement paste throughout their effect on autoclave expansion tests. Cement paste, with different MgO and SO3 percentages in type I and V cements, were cast. The results showed that there is a considerable effect of MgO content on autoclave expansion tests and on the optimum gypsum content in cement. The increase in MgO content results in an increase in the autoclave expansion and a reduction in the optimum gypsum content. The autoclave test is not sensitive to the variation in SO3 content in cement at low MgO value. The sensitivity is increased with increase MgO content. Type V cement appears to be more sensitive to the increase in MgO and SO3 contents than Type I. The X- ray diffraction analysis was also conducted to examine the microstructure and phase distribution of cement paste after autoclave treatment.
