A water-based mixture of multi compounds for adding to fresh concrete to protect the concrete against moisture and moisture-associated problems. A hygroscopic and hydrophilic behavior of its crystallization system within a concrete matrix minimizes moisture transmission through capillaries and connected voids. As a result, the mixture may reduce moisture related problems, such as damage caused by repeated freeze and thaw cycles and chloride ion penetration as from deicing salts, as well as alkali-silica reactions, and other problems.

A water-based mixture of multi compounds for adding to fresh concrete to protect the concrete against moisture and moisture-associated problems. A hygroscopic and hydrophilic behavior of its crystallization system within a concrete matrix minimizes moisture transmission through capillaries and connected voids. As a result, the mixture may reduce moisture related problems, such as damage caused by repeated freeze and thaw cycles and chloride ion penetration as from deicing salts, as well as alkali-silica reactions, and other problems.

Disclosed are a polymer cement-granite composite tomb box and a preparation method thereof. The tomb box has a layered structure or an upper-lower composite structure, where the layered structure is composed of one or two layers of granite slabs and one layer of the polymer cement, and an upper portion of the upper-lower composite structure is made of granite slabs, and an lower portion of the upper-lower composite structure is made of the polymer cement or a combination of the polymer cement and the granite slabs.

Disclosed are a polymer cement-granite composite tomb box and a preparation method thereof. The tomb box has a layered structure or an upper-lower composite structure, where the layered structure is composed of one or two layers of granite slabs and one layer of the polymer cement, and an upper portion of the upper-lower composite structure is made of granite slabs, and an lower portion of the upper-lower composite structure is made of the polymer cement or a combination of the polymer cement and the granite slabs.

The present invention relates to the use of a combination of block polymers and particular compositions in a fluid injected under pressure into an oil-bearing rock, where: the fluid comprises solid particles and/or is brought into contact with solid particles within the oil-bearing rock following the injection thereof, the combination comprises (i) a polymer comprising: —a first block that is adsorbed on at least a portion of the particles; and —a second block, having a composition different from that of the first, and having a weight-average molecular weight of greater than 10 000 g/mol, for example greater than 100 000 g/mol, and that is soluble in the fluid; (ii) particles suitable for providing a gas barrier effect, preferably a latex and/or silica particles.

The present invention relates to the use of a combination of block polymers and particular compositions in a fluid injected under pressure into an oil-bearing rock, where: the fluid comprises solid particles and/or is brought into contact with solid particles within the oil-bearing rock following the injection thereof, the combination comprises (i) a polymer comprising: —a first block that is adsorbed on at least a portion of the particles; and —a second block, having a composition different from that of the first, and having a weight-average molecular weight of greater than 10 000 g/mol, for example greater than 100 000 g/mol, and that is soluble in the fluid; (ii) particles suitable for providing a gas barrier effect, preferably a latex and/or silica particles.

An additive capable of suppressing generation of free water from a cement slurry even under a high temperature environment of 150° C. or more and a silica-based additive that suppresses, in a cement slurry for cementing in oil fields and gas oil fields, free water under high temperature and high pressure environments of 100° C. or more, the silica-based additive containing an aqueous silica sol containing nanosilica particles with a true density of 2.15 g/cm.sup.3 or more and less than 2.30 g/cm.sup.3, and a cement slurry for cementing that contains the silica-based additive.

An additive capable of suppressing generation of free water from a cement slurry even under a high temperature environment of 150° C. or more and a silica-based additive that suppresses, in a cement slurry for cementing in oil fields and gas oil fields, free water under high temperature and high pressure environments of 100° C. or more, the silica-based additive containing an aqueous silica sol containing nanosilica particles with a true density of 2.15 g/cm.sup.3 or more and less than 2.30 g/cm.sup.3, and a cement slurry for cementing that contains the silica-based additive.

A method of forming a cement composition. The method comprises adding to a hydraulic cementitious material a first strength-enhancing agent and a second strength-enhancing agent, wherein the content of total alkali (Na.sub.2O equivalent) in the hydraulic cementitious material is less than or equal to 0.7% by weight of the cementitious material. The first strength-enhancing agent includes a compound represented by structural formula (I): ##STR00001##
and
the second strength-enhancing agent is sodium sulfate, potassium sulfate, or a mixture thereof. The example values of the variables in structural formula (I) and the example amounts of the first and second strength-enhancing agents being added are defined herein.

A method of forming a cement composition. The method comprises adding to a hydraulic cementitious material a first strength-enhancing agent and a second strength-enhancing agent, wherein the content of total alkali (Na.sub.2O equivalent) in the hydraulic cementitious material is less than or equal to 0.7% by weight of the cementitious material. The first strength-enhancing agent includes a compound represented by structural formula (I): ##STR00001##
and
the second strength-enhancing agent is sodium sulfate, potassium sulfate, or a mixture thereof. The example values of the variables in structural formula (I) and the example amounts of the first and second strength-enhancing agents being added are defined herein.