A method of curing a low Ca/Mg cement composition is described that includes providing a predetermined quantity of the low Ca/Mg cement composition in uncured form; and reacting the uncured low Ca/Mg cement composition with a reagent chemical for a time sufficient to cure said cementitious material, wherein said reagent chemical is a compound synthesized from CO.sub.2 and comprises dicarboxylic acids, tricarboxylic acids, or alpha-hydroxycarboxylic acids.

A method of curing a low Ca/Mg cement composition is described that includes providing a predetermined quantity of the low Ca/Mg cement composition in uncured form; and reacting the uncured low Ca/Mg cement composition with a reagent chemical for a time sufficient to cure said cementitious material, wherein said reagent chemical is a compound synthesized from CO.sub.2 and comprises dicarboxylic acids, tricarboxylic acids, or alpha-hydroxycarboxylic acids.

A method of curing a low Ca/Mg cement composition is described that includes providing a predetermined quantity of the low Ca/Mg cement composition in uncured form; and reacting the uncured low Ca/Mg cement composition with a reagent chemical for a time sufficient to cure said cementitious material, wherein said reagent chemical is a compound synthesized from CO.sub.2 and comprises dicarboxylic acids, tricarboxylic acids, or alpha-hydroxycarboxylic acids.

A cementitious composition is provided that includes: (a) pumice; (b) cement; and (c) substantially spherical silica particles.

A cementitious composition is provided that includes: (a) pumice; (b) cement; and (c) substantially spherical silica particles.

A method for controlling the volume expansion of a hydraulically setting composition including steel making slag, the method including a step of adding a silica source to the composition. Furthermore, hydraulically setting compositions obtained by such methods and their uses.

A method for controlling the volume expansion of a hydraulically setting composition including steel making slag, the method including a step of adding a silica source to the composition. Furthermore, hydraulically setting compositions obtained by such methods and their uses.

A tubing string may include a swellable metal material for providing a seal downhole. The swellable metal material may react with a silica material and a water-based fluid to cause the swellable metal material to swell and form a seal within a flow path defined in part by the tubing string.

Disclosed are composite materials comprising a porous, carbonated, calcium silicate ceramic having a microstructure comprising interconnected open pores; where the calcium silicate surface defining the pores is partially or completely coated with an amorphous silica layer, and the silica coating comprises an overlayer of calcium carbonate crystals; where the silica coating and calcium carbonate overlayer form a network that interconnects throughout the ceramic microstructure, but do not completely occlude the pores. Also disclosed are methods of forming such composite materials.

Disclosed are composite materials comprising a porous, carbonated, calcium silicate ceramic having a microstructure comprising interconnected open pores; where the calcium silicate surface defining the pores is partially or completely coated with an amorphous silica layer, and the silica coating comprises an overlayer of calcium carbonate crystals; where the silica coating and calcium carbonate overlayer form a network that interconnects throughout the ceramic microstructure, but do not completely occlude the pores. Also disclosed are methods of forming such composite materials.