Abstract
This paper discuss the synthesis of standard hydrates and the drying method for XRD quantitive analysis of C3A-CaSO4·2H2O-CaCO3-Na2SO4-H2O system. Monocarboaluminate was synthesized by using of mixture of C3A and CaCO3 (mole ratio 1 : 1). Combined water of monocarboaluminate (mole ratio) was 10.4 by aspirator drying after 3 h. Hemicarboaluminate was formed by the mixture of C3A : CaCO3 : Ca (OH) 2 = 1 : 1/2 : 1/2 at 28 day. Combined water of hemicarboaluminate was 11.2 by aspirator drying after 3 h. Chemical compositions of ettringite and monosulfoaluminate were C3A·3CaSO4·31.4H2O and C3A·CaSO4·11.5H2O respectively by the same drying method. Single phase of U was formed by the mixture of C3A : CaSO4·2H2O : Na2SO4 = 1 : 0.9 : 0.5. The chemical composition of U phase may be C3A·0.9CaSO4·0.5Na2SO4·13H2O.
