An accelerator powder for cement and also rapid-setting binder compositions which contain the accelerator powder and the use in mortar or concrete. The accelerator powder includes from 10 to 99.7% by weight of a water-insoluble mineral powder P and from 0.3 to 90% by weight of at least one compound V selected from the group consisting of alkali metal halides and alkaline earth metal halides, alkali metal nitrates and alkaline earth metal nitrates, alkali metal nitrites and alkaline earth metal nitrites, alkali metal thiocyanates and alkaline earth metal thiocyanates and hydroxyalkylamines or salts thereof, and mixtures thereof.

A method of reducing corrosion in tubular strings installed in wellbores includes dispensing an accelerated cement composition into a wellbore annulus, a casing-casing annulus, or both, the accelerated cement composition comprising a cement composition and an accelerant composition, where: the cement composition comprises a cement precursor and water; the accelerant composition comprises triethanolamine; and a concentration of the triethanolamine in the accelerated cement composition is greater than or equal to 10,000 parts per million by weight; allowing the accelerated cement composition to cure in the annulus to form a cured cement, where the triethanolamine reacts with a metal of the tubular string, the reaction forming a protective layer on the surfaces of the tubular string that inhibits dissolution of iron from the metal of the tubular string.

A fast-curing mineral binder mixture includes a zirconium(IV)-based accelerator, a cement which includes at least one component selected from the compounds 3CaO*Al.sub.2O.sub.3, 12CaO*7Al.sub.2O.sub.3, CaO*Al.sub.2O.sub.3, CaO*2Al.sub.2O.sub.3, CaO*6Al.sub.2O.sub.3 and 4CaO*3Al.sub.2O.sub.3*SO.sub.3, and 15 to 80 wt % of a sulfate carrier, wherein the wt % is based on a weight of the fast-curing mineral binder mixture. The fast-curing mineral binder mixture can optionally include at least one alkaline component and/or at least one additive.

Disclosed are a barium slag-modified aluminate quick-hardening special cementing material and a preparation method thereof, wherein the raw materials for the preparation of the barium slag-modified aluminate quick-hardening special cementing material includes, in parts by weight: 10-12 parts of aluminate cement clinker, 2-3 parts of barium slag powder, 1.5-2 parts of sulfate material, and 0-1.5 parts of early-setting agent. The present invention, on the basis of ensuring the original advantages of aluminate cement, can increase the long-term strength, durability, and economy, and solve the possible environmental problems caused by the barium slag, making it more suitable for use in various engineering projects.

Trona-accelerated composition for backfilling trenches are described. The compositions consist of aggregate (e.g., sand), Portland cement, Trona, water and sometimes air. The compositions may have a compressive strength of between 10 psi and 100 psi after 4 hours, a compressive strength of between 75 psi and 500 psi after 28 days, and a penetration resistance of between 4.5 tsf and 200 tsf after 4 hours. Also disclosed are methods of filling a trench with fast-setting flowable fill.

A novel cement composition for 3D printing including has 90% to 99.5% by weight of one or more cements selected from a Portland cement, an aluminous cement, a sulphoaluminous cement and a prompt natural cement; and has 0.5% to 10% by weight of a silicoaluminous filler having a specific surface area of at least 5 m.sup.2/g, as well as a method for implementing the composition.

The present invention relates to the use of a soluble magnesium compound for adjusting, in particular reducing, the viscosity of an aluminum sulfate suspension.

A method of making a setting type compound by injecting an activator compound into a plaster compound wherein the activator compound tube is coaxial and within the plaster compound tube, each at the same flowrate, the same pressure and the same viscosity. The cross sectional transverse areas of an annulus containing the plaster compound and the hole in the annulus containing the activator compound are the same.

A method of producing magnesium cement. The method may comprise mixing water at a temperature of between approximately 50 C. and 100 C., a magnesium oxygen-containing compound and a magnesium salt. In some embodiments, the water is heated to a temperature of between approximately 70 C. and 90 C. The magnesium oxygen-containing compound may comprise one or more of magnesium oxide and magnesium hydroxide. The magnesium salt may comprise one or more of magnesium acetate, magnesium bromide, magnesium oxalate, magnesium thiosulfate, magnesium phosphate, magnesium nitrate, magnesium silicate, a magnesium chloride in any hydration state, anhydrous magnesium chloride, hexahydrate magnesium chloride, a magnesium sulfate in any hydration state, anhydrous magnesium sulfate, heptahydrate magnesium sulfate and magnesium carbonate.

A concrete composition having an optimized formulation and suitable for 3-D printing is provided. The composition may include a hydraulic cement composition, aggregate, cement and/or aggregate by-product dust, one or more rheology modifiers, a plasticizer, fibers, and a sufficient amount of water to effect setting of the composition. Optionally the concrete composition may include a setting agent. A method for 3D printing multiple layers of the concrete composition is also provided.