A powder essentially composed of aggregates based on boron nitride, the powder exhibiting an overall chemical composition, as percentages by weight, including between 40 and 45% of boron, between 53 and 57% of nitrogen, less than 400 ppm by weight of calcium, less than 5%, in total, of other elements and more than 90% of boron nitride, limit included, as percentage by weight and on the basis of the combined crystalline phases, a mean circularity of greater than or equal to 0.90, a median pore size of less than or equal to 1.5 m and an apparent porosity of less than or equal to 55%.

A method of pressure-pumping a ready-mixed concrete includes pouring a preceding material for pumping into a piping, then, pouring the ready-mixed concrete into the piping, and pressure-pumping the preceding material and the ready-mixed concrete, so that a lubricant layer formed of the preceding material is formed on an inner surface of the piping to thereby pressure-pump the ready-mixed concrete inside the lubricant layer made of the preceding material. The preceding material includes calcium carbonate as a main material, to which cellulose nanofibers and erythorobic acid are added, and an amount of the cellulose nanofibers is 0.005 wt % or more.

A method of pressure-pumping a ready-mixed concrete includes pouring a preceding material for pumping into a piping, then, pouring the ready-mixed concrete into the piping, and pressure-pumping the preceding material and the ready-mixed concrete, so that a lubricant layer formed of the preceding material is formed on an inner surface of the piping to thereby pressure-pump the ready-mixed concrete inside the lubricant layer made of the preceding material. The preceding material includes calcium carbonate as a main material, to which cellulose nanofibers and erythorobic acid are added, and an amount of the cellulose nanofibers is 0.005 wt % or more.

Cement compositions that can capture carbon dioxide and related methods are generally described.

Cement compositions that can capture carbon dioxide and related methods are generally described.

A method for suspending lightweight beads in a fluid includes combining lightweight beads, a fluid, and a surfactant to form a liquid additive. The liquid additive may be used to reduce the density of a wellbore fluid. The liquid additive or wellbore fluid can be combined with a cementitious material to form a lightweight cement composition.

A method for suspending lightweight beads in a fluid includes combining lightweight beads, a fluid, and a surfactant to form a liquid additive. The liquid additive may be used to reduce the density of a wellbore fluid. The liquid additive or wellbore fluid can be combined with a cementitious material to form a lightweight cement composition.

Methods and compositions are provided that utilize high-alumina refractory aluminosilicate pozzolans in well cementing. An embodiment discloses a method of cementing comprising: introducing a cement composition into a subterranean formation, wherein the cement composition comprises: a component selected from the group consisting of cement kiln dust, Portland cement, and any combination thereof; a high-alumina refractory aluminosilicate pozzolan; and water; and allowing the cement composition to set.

Methods and compositions are provided that utilize high-alumina refractory aluminosilicate pozzolans in well cementing. An embodiment discloses a method of cementing comprising: introducing a cement composition into a subterranean formation, wherein the cement composition comprises: a component selected from the group consisting of cement kiln dust, Portland cement, and any combination thereof; a high-alumina refractory aluminosilicate pozzolan; and water; and allowing the cement composition to set.

A fiber reinforced concrete composition which cures to a cured fiber reinforced concrete composite following addition of water, the cured fiber reinforced concrete composite having a density from about 700 to 1000 kg/m.sup.3 and a compressive strength from about 5 to 15 MPa. A fiber reinforced concrete composition includes a brittle inorganic matrix precursor, a plurality of reinforcing fibers present in a range from 0.5 volume percent to less than 4 volume percent based on the total volume of the cured fiber reinforced concrete composite, and lightweight aggregate having a mean particle size in the range of 10 m to 1000 m, in an amount effective to achieve a target density in the cured composite not more than 1000 kg/m.sup.3. The reinforcing fibers include polypropylene fibers. The lightweight aggregate can include hollow fly ash spheres and glass microspheres. An acrylic admixture can be added to the composition.