A geopolymer cementing fluid with controllable thickening time includes the following components in parts by weight: 100 parts of a cementitious material, 10 parts-30 parts of an activator, 0.2 parts-5 parts of a retarder, 0.4 parts-4 parts of an anti-settling agent, and 30 parts-70 parts of water. The geopolymer cementing fluid of the present invention has the advantages of controllable thickening time, excellent compressive strength, good settlement stability, good rheological properties, green and eco-friendly, and the like. The geopolymer cementing fluid can be better suited for the operations of oil and gas well cementing and ensure cementing safety.

It is provided a method of cementing comprising a) providing a cement slurry by mixing: i) a cement composition comprising an cement and an amount of magnetic nanoparticles from 0.01 wt. % to 10 wt. % relative to the amount of cement (0.01% to 10% BWOC), wherein the magnetic nanoparticles have a mean particle size determined by Transmission Electron Microscopy (TEM) from 10 nm to 50 nm and a crystallite size determined by the Scherrer equation which is at least an 80% the mean particle size; and ii) water; and b) applying to the cement slurry an alternating magnetic field of from 25 mT to 60 mT at a frequency from 50 kHz to 200 kHz) in order to set the cement slurry. It is also provided the mentioned cementing composition and an article of manufacture obtainable by the method of cementing.

Disclosed is a composite gypsum board comprising a set gypsum core disposed between face (e.g., Manila) and back (e.g., Newsline) cover sheets. The set gypsum core is formed from a core slurry comprising stucco, water, and optional additives, such as foaming agent, migrating starch, accelerator, retarder, dispersant, etc. A dense layer formed from a dense layer slurry comprising stucco, water, fiber (e.g., paper fiber), and optionally, strength-enhancing starch, is disposed between the core and the face paper. The dense layer slurry contains a greater concentration of fiber, and optionally, strength-enhancing starch, than the core slurry, but the concentration of one or more other additives (e.g., accelerator, retarder, dispersant, or combinations thereof) is lower or the same in the dense slurry as compared with the core slurry. Also disclosed is a method of making board using one board mixer. In embodiments, paper fiber is added to water to form a suspension. The suspension is introduced, while in a non-laminar state, into the dense slurry. Further disclosed is apparatus, such as an extractor and an additive injection system, which can be a part of a cementitious slurry mixing and dispensing assembly.

Disclosed is a composite gypsum board comprising a set gypsum core disposed between face (e.g., Manila) and back (e.g., Newsline) cover sheets. The set gypsum core is formed from a core slurry comprising stucco, water, and optional additives, such as foaming agent, migrating starch, accelerator, retarder, dispersant, etc. A dense layer formed from a dense layer slurry comprising stucco, water, fiber (e.g., paper fiber), and optionally, strength-enhancing starch, is disposed between the core and the face paper. The dense layer slurry contains a greater concentration of fiber, and optionally, strength-enhancing starch, than the core slurry, but the concentration of one or more other additives (e.g., accelerator, retarder, dispersant, or combinations thereof) is lower or the same in the dense slurry as compared with the core slurry. Also disclosed is a method of making board using one board mixer. In embodiments, paper fiber is added to water to form a suspension. The suspension is introduced, while in a non-laminar state, into the dense slurry. Further disclosed is apparatus, such as an extractor and an additive injection system, which can be a part of a cementitious slurry mixing and dispensing assembly.

Corrosion mitigating cement compositions and methods for their preparation are provided. The cement compositions are derived from self-cementing pozzolans and chemical accelerators, retarders, mechanical strength modifiers and corrosion inhibitors. The corrosion inhibitors include boron compounds such as boric acid. Concretes prepared using the cement compositions possess low conductivity and a conductivity which further decreases with aging.

Corrosion mitigating cement compositions and methods for their preparation are provided. The cement compositions are derived from self-cementing pozzolans and chemical accelerators, retarders, mechanical strength modifiers and corrosion inhibitors. The corrosion inhibitors include boron compounds such as boric acid. Concretes prepared using the cement compositions possess low conductivity and a conductivity which further decreases with aging.

The present invention relates to additives and, more specifically, the use of biochar, in concrete and other cementitious materials to provide for building materials that have a lower carbon footprint than their traditional counterparts. Traditional methods for production of cement produce large amount of carbon dioxide (CO2). When coupled with the massive demand for cement building materials around the world, this means that the cement production has a significant impact on the amount of CO2 produced globally. By including biochar and other additives along with, or instead of some traditional components of cement, one may be able to provide for cementitious building materials that sequester carbon, rather than release it.

A cementitious composition includes a Portland cement and at least one non-Portland hydratable cement selected from the group consisting of calcium sulfoaluminate cement, a calcium aluminosilicate cement, and calcium aluminate cement, wherein the Portland cement has a content of at least 10 percent based on the total weight of the non-Portland hydratable cement powder, wherein the cementitious composition is free of latex bonding agents, and wherein the cementitious composition is bondable to asphalt. The cementitious composition may also include an aggregate in the form of asphalt millings.

A cementitious composition includes a Portland cement and at least one non-Portland hydratable cement selected from the group consisting of calcium sulfoaluminate cement, a calcium aluminosilicate cement, and calcium aluminate cement, wherein the Portland cement has a content of at least 10 percent based on the total weight of the non-Portland hydratable cement powder, wherein the cementitious composition is free of latex bonding agents, and wherein the cementitious composition is bondable to asphalt. The cementitious composition may also include an aggregate in the form of asphalt millings.

Gypsum panels and methods for their manufacture are provided herein. The gypsum panels include a gypsum core having a first surface and a second opposed surface and a first fiberglass mat associated with the first surface of the gypsum core, such that gypsum from the gypsum core penetrates at least a portion of the first fiberglass mat.