Investigation on the Blended Cement Mixture of Sintered Clinker of Calcium Sulfoaluminate Cement and Granulated Blast Furnace Slag

In this paper, we present studies in laboratory where we used bauxite Tan Rai and synthetic gypsum DAP Dinh Vu to fabricate cement clinker of calcium sulfoaluminate. Results of compositional analysis by XRD revealed major phases of ye’elimite 4CaO.3Al₂O₃.SO₃ (C₄A₃Š), belite 2CaO.SiO₂ (C₂S), anhydrite CaO.SO₃ (CŠ) in the sintered product. With the aim of combining two hydration mechanisms of CSA cement (rapid) and slag cement (slow), we then formulated blended cement from mixture of 15.58%wt CSA clinker and 73.36%wt fine ground granulated blast furnace slag and 11.06%wt synthetic gypsum. Specification tests of prepared cement were conducted conforming to the requirement of standard BS EN 15743 for supersulfated cement. In term of strength development, we noted quite high strength gain after 7 days in both tap water and sea water mixing cement. The global compressive strength of cement mortar met the grade 40 MPa of standard. Considering its practical application, we discuss on the perspective using this special cement for concrete under severe condition after taking into account further study on durability.