Effect of Gypsum Content on Corrosion Resistance of Alite-Barium Calcium Sulphoaluminate Cement

摘要

Effect of gypsum content on the sulfate and seawater resistance of alite-barium calcium sulphoaluminate cement was studied. Portland cement was taken for comparison. The composition and microstructure of hardened cement pastes were analyzed by means of Xray diffraction and scanning electron microscope. The results show that gypsum affects the tightness of alite-barium calcium sulphoaluminate cement pastes and further influences the ability to resist seawater and sulfate corrosion. The mineral constitution 2.75CaO-0.25BaO-3Al2O3BaSO4 has the best of prominent high strength, fast hydration rate and short setting time, etc. Because 2.75CaO-0.25BaO-3Al2O3-BaSO4 instead of some or all of C3A in Portland cement clinker, this cement can be defined as Alite-barium calcium sulphoaluminate cement. Under appropriate dosage in gypsum, Alite - barium calcium sulphoaluminate cement hydrate and form ettringite. There is much ettringite which increased density of hardened cement pastes, so that it is hard for seawater and sulfate enter the pastes. Compared with the Portland cement, alite-barium calcium sulphoaluminate cement have better corrosionresistant and the corrosion resistance coefficient to the sulfate and seawater are 1.31 and 1.08, respectively. The corrosion resistance coefficient of Portland cement are 0.94,0.90, respectively. At the same time, the mechanism sulfate resistance of alitebarium calcium sulphoaluminate cement is discussed.