Effects of Different Kinds of Gypsum On Properties of Portland Cement

The effects of different gypsum on portland cement properties and hydration process were investigated through analysis testings on raw materials property, cement physicomechanical property and hydration product by SEM. Test results show that cement strength would be decreased when adding anhydrite than adding dihydrate gypsum. The cement which added with semi-hydrated gypsum need more water, but less strength is obtained in early stage. Phosphorous gypsum makes cement condensation time prolonged, while give no evidence influence on cement strength. Using fluorine gypsum as retardant, good effect has obtained on cement strength and no defect is found on cement properties.