Provided is a cement composition that has high fluidity (for example, a 0-drop flow value of 200 mm or more) before curing and exhibits high compressive strength (for example, 320 N/mm.sup.2 or more) after curing. The cement composition includes a cement, a silica fume having a BET specific surface area of from 10 m.sup.2/g to 25 m.sup.2/g, an inorganic powder having a 50% cumulative particle size of from 0.8 μm to 5 μm, a fine aggregate having a maximum particle size of 1.2 mm or less, a water reducing agent, an antifoaming agent, and water. The ratio of the cement is from 55 vol % to 65 vol %, the ratio of the silica fume is from 5 vol % to 25 vol %, and the ratio of the inorganic powder is from 15 vol % to 35 vol % in the total amount of 100 vol % of the cement, the silica fume, and the inorganic powder.

The present invention relates to a water redispersible polymer powder (RDP) which comprises a co-dried admixture of a water-insoluble film forming polymer, a colloidal stabilizer and rubber particles. The presence of rubber within the RDP does not significantly affect redispersibility and may, when incorporated into hydraulically-binding compositions, provide an improvement in the physical properties of the resultant hydraulically bound composition.

The present invention relates to a water redispersible polymer powder (RDP) which comprises a co-dried admixture of a water-insoluble film forming polymer, a colloidal stabilizer and rubber particles. The presence of rubber within the RDP does not significantly affect redispersibility and may, when incorporated into hydraulically-binding compositions, provide an improvement in the physical properties of the resultant hydraulically bound composition.

A composition includes an aqueous colloidal dispersion of a nanomaterial. The nanomaterial includes, disposed on a surface of the nanomaterial, a first coupling agent including silane and a functional group including an amino acid. The nanomaterial includes, disposed on the surface of the nanomaterial, a second coupling agent including silane and a polymer with a molecular weight between 1,000 and 20,000.

A composition includes an aqueous colloidal dispersion of a nanomaterial. The nanomaterial includes, disposed on a surface of the nanomaterial, a first coupling agent including silane and a functional group including an amino acid. The nanomaterial includes, disposed on the surface of the nanomaterial, a second coupling agent including silane and a polymer with a molecular weight between 1,000 and 20,000.

The invention comprises a composition comprising hyaloclastite having a volume-based mean particle size of less than or equal to 40 μm. The invention also comprises a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm. The invention further comprises a cementitious-based material comprising aggregate, a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm and water sufficient to hydrate the cementitious material. A method of using the composition of the present invention is also disclosed.

The invention comprises a composition comprising hyaloclastite having a volume-based mean particle size of less than or equal to 40 μm. The invention also comprises a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm. The invention further comprises a cementitious-based material comprising aggregate, a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm and water sufficient to hydrate the cementitious material. A method of using the composition of the present invention is also disclosed.

A liquid concentrate for use in a well that penetrates a subterranean formation comprising: a base liquid; and a strength retrogression additive, wherein the strength retrogression additive consists of particles of silicon dioxide containing crystalline regions, wherein the liquid concentrate has an activity of at least 40%. A method of cementing in a subterranean formation comprising: providing the liquid concentrate; forming a cement composition by adding a predetermined volume of the liquid concentrate to at least cement and water; and introducing the cement composition into the subterranean formation

A liquid concentrate for use in a well that penetrates a subterranean formation comprising: a base liquid; and a strength retrogression additive, wherein the strength retrogression additive consists of particles of silicon dioxide containing crystalline regions, wherein the liquid concentrate has an activity of at least 40%. A method of cementing in a subterranean formation comprising: providing the liquid concentrate; forming a cement composition by adding a predetermined volume of the liquid concentrate to at least cement and water; and introducing the cement composition into the subterranean formation

A cement slurry composition, containing hydraulic cement, water, and from 1 to less than 4% of an organically modified nanoclay. A method for cementing a high pressure high temperature well by pumping the cement composition of claim 1 between a casing and a formation of a well bore to fill a gap between the casing and the formation, and allowing the cement to harden.