CALCINATION CONDITION OF BELITE-CALCIUM BARIUM SULPHOALUMINATE CEMENT AND ITS PERFORMANCE

The synthesis conditions of belite-calcium barium sulphoaluminate cement clinker were studied by the orthogonal test method.The experimental results show that the optimal sintering temperature,sintering time and cooling method are 1350℃,90 min and quick cooling respectively,and the optimal gypsum content in the cement is 5% in the cement.Under these processing conditions, the compressive strength of belite-barium calcium sulphoaluminate cement reaches 26.4 MPa and 80.4 MPa at 3 d and 28 d curing ages respectively.Gypsum can promote cement hydration and enable ettringite (AFt) to form quickly in the early period of hydration, which results in an increase of the early strength of the cement.The constitution,structure and morphology of the clinker and hydra- tion products were analyzed by means of scanning electron microscopy and X-ray diffraction.The main minerals of the clinker are belite (C_2S),alite (C_3S) and calcium barium sulphoaluminat (C_(2.75)B_(1.25)A_3(?)),and the main hydrates are hydrated calcium silicate (C-S-H),AFt and calcium hydroxide (CH).