| abstract |
The tectoaluminosilicate cement disclosed, which contains K, Ca and aluminosilicates plus, optionally, Li, Na and Mg, is characterized in that it contains: a phyllosilicate dehydroxylated at a temperature between 500 and 900 °C, reactive silica, reactive calcium aluminosilicate glass with a Ca:Si ratio of » 1 and alkali-metal activator of total formula (I): a(M2O) * x(SiO2) * y(H2O) in which M = Li, Na or K, a = 0-4, x = 0-5 and y = 3-20, the overall Si:Al ratio being » 1. The tectoaluminosilicate cement preferably contains at least one alkali-metal hydroxide. The dehydroxylated phyllosilicate may be a metakaolin giving tectosilicate structures in the presence of alkali-metal components. The reactive silica may be a de-aluminated phyllosilicate, a silica gel, an aluminosilicate, thermally activated by an alkali metal, obtained by sintering a silicate within an alkali metal carbonate at a temperature between 800 and 1,200 °C, the alkali metal component and aluminosilicate being mixed in the ratio 1:6 to 1:1, and/or microsilica (''fumed'' silica). The alkali metal activator may be prepared in situ from the de-aluminated phyllosilicate and/or from the silica gel in the presence of the alkali-metal hydroxide. A binder matrix obtained from the tectoaluminosilicate cement by reacting with water in the ratio 3:1 to 6:1 is characterized by total formula (II): (Li, Na)0-7k1-6Mg1-0Ca3-0[Al4Si6-14O21-36] . (0-15H2O). |