A process for preparing powdered dispersants comprising at least 90% by weight of at least one copolymer CP of the polycarboxylate ether type. The powdered dispersants can be easily dispersed in water. The invention also relates to the use of such powdered dispersants in mineral binder compositions, in particular dry mortars, concrete or gypsum formulations.

A regulating cementitious material for promoting hydration of Portland cement is provided. The regulating cementitious material may include ingredients by weight as follows: ye'elimite, 27˜68 parts; anhydrite, 29˜68 parts; lithium nitrite, 2˜5 parts; ethylene glycol monoisopropanolamine, 0.14˜0.29 parts; triethanolamine acetate, 0.04˜0.09 parts; and polyglycerol, 0.04˜0.09 parts. An early strength of Portland cement can be improved through a cooperative hydration between minerals and an enhanced solubilization of a complexing agent.

A concrete and asphalt repair coating formulation includes a cement component and an aggregate component. The cement component includes a calcium sulfoaluminate cement and a Portland cement. The aggregate component includes coarse aggregates between 125-500 microns in diameter and fine aggregates between 5-62.5 microns in diameter.

A preparation method for a concrete additive for a maritime work environment includes: S1, compounding a volcanic ash material containing aluminum oxide and lime in proportion, loading a mixture into a sugar coating machine, and spraying a proper amount of alcohol, to prepare spherical particles; S2, adding the spherical particles in S1 and cement into the sugar coating machine, uniformly spraying deionized water in a rotating process, and coating surface layers of the spherical particles with a layer of cement for maintenance; and S3, placing the maintained particles in S2 into a hydrophobic emulsion, and coating the surface layers of the particles with a layer of hydrophobic emulsion, to obtain a concrete additive.

A synchronous single-liquid grouting slurry, its technology and application for large diameter shield engineering under water-rich, high-pressure and weak soil strata conditions, comprising raw materials: 1050-1200 parts of gold tailing, 420-480 parts of silicate cement clinker, 220-240 parts of fly ash, 45-120 parts of waste clay brick, 65-95 parts of slag, 25-45 parts of limestone tailing, 70-80 parts of steel slag, 30-45 parts of silica fume, 15-22 parts of desulfurized gypsum, and 9-15 parts of quick-setting and early-strength composite additive. The invention controls the d.sub.50, d.sub.85 and d.sub.95 of the material particles as 35-40, 42-48 and 50-55 μm, respectively. Gold tailing with the particle size of 120-600 μm being used as the fine aggregate, their volume fractions are 40-60%. The slurry production technique, comprising crushing-sieving-superfine ball milling-homogenization-particle size classification-variable speed mixing being developed. The shield tail eight-point grouting technique is being developed for filling.

Disclosed are a method for separately preparing light magnesium oxide and calcium oxide by using dolomite and an application thereof in preparation of a calcium-magnesium composite expanding agent. In the method for preparing light magnesium oxide and calcium oxide, based on the difference in decomposition temperature between magnesium carbonate and calcium carbonate during the calcination and decomposition of dolomite and the difference in the weight of the materials after decomposition, the effective separation of magnesium oxide and calcium oxide is realized by a one-step method, thus separately preparing light magnesium oxide and light calcium oxide. The calcium-magnesium composite expanding agent is prepared by using the foregoing light magnesium oxide and calcium oxide. On the one hand, the present invention solves the problem of the limited origin of the light magnesium oxide raw material of the magnesium expanding component in the calcium-magnesium composite expanding agent.

Disclosed are a method for separately preparing light magnesium oxide and calcium oxide by using dolomite and an application thereof in preparation of a calcium-magnesium composite expanding agent. In the method for preparing light magnesium oxide and calcium oxide, based on the difference in decomposition temperature between magnesium carbonate and calcium carbonate during the calcination and decomposition of dolomite and the difference in the weight of the materials after decomposition, the effective separation of magnesium oxide and calcium oxide is realized by a one-step method, thus separately preparing light magnesium oxide and light calcium oxide. The calcium-magnesium composite expanding agent is prepared by using the foregoing light magnesium oxide and calcium oxide. On the one hand, the present invention solves the problem of the limited origin of the light magnesium oxide raw material of the magnesium expanding component in the calcium-magnesium composite expanding agent.

A composite cementitious feedstock includes mineral rock agglutinates, super absorbent polymer (SAP) particles, cement particles, and a binder. Each of the agglutinates has irregular surface regions and cavities originating at the irregular surface regions. At least a portion of the SAP particles and cement particles are disposed on the irregular surface regions and in the cavities. The binder coheres the agglutinates, SAP particles, and cement particles.

The present invention is the production method of ready injection material which aims to develop natural hydraulic lime in nano size by using a single raw material.

A powdered quick-setting agent containing a calcium aluminate and a sodium silicate, preferably further containing at least one selected from the group consisting of an alkali metal sulfate, an alkaline earth metal sulfate, and an aluminum sulfate.