Inorganic cohesion agent for self-compacting cement pastes

Abstract

The present invention relates to an inorganic cohesion agent for self-compacting cement pastes consisting of a co-precipitated SiO 2 /CaCO 3 mixture.

1 . An inorganic cohesion agent for self-compacting cement pastes, consisting of a co-precipitated SiO 2 /CaCO 3  mixture.  
     
     
         2 . The cohesion agent according to  claim 1 , characterized in that the co-precipitated mixture of silica and calcium carbonates is obtained starting from natural or synthetic calcium silicates, crystalline or amorphous, hydrated or non-hydrated, or their mixtures, cements or cement clinkers.  
     
     
         3 . The cohesion agent according to  claim 1 , characterized in that the co-precipitated SiO 2 /CaCO 3  mixture is in aqueous suspension.  
     
     
         4 . The cohesion agent according to  claim 1 , characterized in that the co-precipitated SiO 2 /CaCO 3  mixture is in the dry state.  
     
     
         5 . The cohesion agent according to  claim 1 , characterized in that the co-precipitated SiO 2 /CaCO 3  mixture has a weight ratio SiO 2 /CaCO 3  ranging from 1.2 to 0.1.  
     
     
         6 . The cohesion agent according to  claim 1 , characterized in that the co-precipitated SiO 2 /CaCO 3  mixture contains up to 50% of other components in mass.  
     
     
         7 . The cohesion agent according to  claim 6 , characterized in that the other components are calcium silicates (non-reacted or transformed), for example those indicated as CSH, and/or metallic oxides.  
     
     
         8 . The cohesion agent according to  claim 1 , characterized in that the specific surface of the co-precipitated mixture ranges from 20 to 100 m 2 /g.  
     
     
         9 . The cohesion agent according to  claim 1 , characterized in that the co-precipitated SiO 2 /CaCO 3  mixture is present in dosages ranging from 1 to 30% with respect to the weight of the cement.  
     
     
         10 . The cohesion agent according to  claim 1 , characterized in that the co-precipitated SiO 2 /CaCO 3  mixture is present in dosages ranging from 5 to 15% with respect to the weight of the cement.  
     
     
         11 . The cohesion agent according to  claim 1 , which can be obtained by means of a process for the production of silica, in which calcium silicate crystals are put in contact with CO 2  in the presence of water and converted to silica, having the same configuration as silicate crystals, and to calcium carbonate particles attached to amorphous silica particles.  
     
     
         12 . Use of the agent according to any of the previous claims, for self-compacting cement pastes.  
     
     
         13 . Self-compacting concrete obtained with the use of an inorganic cohesion agent according to any of the claims from  1  to  10 .  
     
     
         14 . Recovery mortars or pastes obtained by the use of an inorganic cohesion agent according to any of the claims from  1  to  10 .