CALCIUMSULFATE UND EINE ANORGANISCHE CALCIUMALUMINATVERBINDUNG ENTHALTENDE ETTRINGITBINDEMITTEL FÜR DICHTEN MÖRTEL

摘要

Ettringite binder for dense mortar comprises calcium sulfates and a mineral compound of aluminates comprising soluble oxides of calcium (C) and aluminum (A) combined in one or more crystalline and/or amorphous phases. The molar ratio C/A of the mineral compound is 1.2-2.7. The total weight of the phases (C+A) is at least 30% of the total weight of the mineral compound. Preferred Features: The weight ratio of the mineral compound of calcium aluminates to calcium sulfate is 0.5-4, more preferably 1.5-3. The molar ratio of calcium sulfate to aluminum oxide (A) in the ettringite binder is 0.5-2, more preferably 0.6-1.8, and especially 0.8-1.7. The molar ratio C/A of the mineral compound of calcium aluminates is 1.3-2.5, more preferably 1.6-2. The ratio of water to solids, on mixing the ettringite binder with water, is less than 0.5. The mortar may not comprise Portland cement and/or hydraulic lime, or may comprise Portland cement and/or hydraulic lime in an amount less than 3.5 weight % with respect to the total weight of the dry mortar. The total amount of the phases (C+A) is at least 50% of the total weight of the mineral compound of calcium aluminates. Independent claims are given for: (a) a dry mortar containing (in weight % with respect to the total weight of the dry mortar): the invented ettringite binder 15-75; limestone or siliceous sand fillers 25-85; lime and/or Portland cement 0-3.5; dispersible polymer powder 0-8 and/or a solid-liquid polymer dispersion 0-20; and rheological and/or set-time control additives; (b) a dry mortar containing (in weight % with respect to the total weight of the dry mortar): the invented ettringite binder 20-50; limestone or siliceous sand fillers 50-80; lime and/or Portland cement 0-0.5; dispersible polymer powder 0-5 and/or a solid-liquid polymer dispersion 0-15; and rheological additives 0.1-0.5 and/or set-time control additives 0.1-0.5; (c) a wet mortar obtained by mixing the dry mortar with water in an amount such that the weight ratio of water to solids is less than 0.5. (d) Use of the mineral compound of aluminates in the formulation of an ettringite binder, and in the formulation of the dry and wet mortars.