Accelerating admixture for cementitious compositions

摘要

The present invention describes a hardening accelerating admixture for hydraulic binders, the accelerator being based on transition metal silicate hydrates having the general formula: aMexOy bMO cAl2O3 SiO2 dH2O 1) where—Me represents a transition metal whose molar coefficient a is in a range between 0.001 and 2, preferably between 0.01 and 1; —M represents an alkaline earth metal whose molar coefficient b is in a range between 0 and 2, preferably between 0.3 and 1.6; —The molar coefficient c for Al2O3 is in a range between 0 and 2, preferably between 0.1 and 1; —H2O represents the hydration water of the silicate hydrate whose molar coefficient d can vary within a wide range between 0.5 and 20; x and y can both be equal to 1 or different, depending on the valence of the transition metal, given that the valence of the oxygen atom in the metal oxide is equal to 2.

主权项

1. A method of accelerating setting and hardening of hydraylic binders, said method comprising:
adding to said hydraulic binders from 0.01% to 40% with respect to the weight of the binders of a transition metal silicate hydrate having general formula
aMexOy.bMO.cAl2O3.SiO2.dH2O  1) where
Me represents a transition metal whose molar coefficient a is in a range between 0.001 and 2;M represents an alkaline earth metal whose molar coefficient b is in a range between 0 and 2;The molar coefficient c for Al2O3 is in a range between 0 and 2;H2O represents the hydration water of the silicate hydrate whose molar coefficient d vary within a wide range between 0.5 and 20;x and y both be equal to 1 or different, depending on the valence of the transition metal, given that the valence of the oxygen atom in the metal oxide is equal to 2 and being characterized by the presence of particles with a diameter lower than 1,000 nm, whereby accelerating the setting and hardening of said hydraulic binders.