A method of treating a lost circulation zone in a wellbore includes contacting an accelerant composition comprising triethanolamine with a cement composition in the lost circulation zone, the cement composition comprising at least: from 1 weight percent (wt. %) to 90 wt. % cement precursor based on the total weight of the cement composition; and from 5 wt. % to 70 wt. % water based on the total weight of the cement composition; where a weight ratio of triethanolamine to the cement precursor is from 0.1 percent (%) to 60%; and curing the cement composition in the lost circulation zone to form a cured cement, where the triethanolamine accelerates the curing rate of the cement composition and the cured cement seals the lost circulation zone.

A calcium sulphate-based product including gypsum and a shrinkage resistance additive. The shrinkage resistance additive is a metal nitrate, hydroxide, acetate or sulphate and is preferably provided in an amount greater than 4 wt % (based on the amount of additive and gypsum). The additive may be a nitrate of an alkali metal (e.g. potassium), an alkaline earth metal (e.g. magnesium or calcium), a transition metal (e.g. iron or zinc) or aluminium.

A calcium sulphate-based product including gypsum and a shrinkage resistance additive. The shrinkage resistance additive is a metal nitrate, hydroxide, acetate or sulphate and is preferably provided in an amount greater than 4 wt % (based on the amount of additive and gypsum). The additive may be a nitrate of an alkali metal (e.g. potassium), an alkaline earth metal (e.g. magnesium or calcium), a transition metal (e.g. iron or zinc) or aluminium.

Method and composition for producing aggregates from cement and concrete, including residual or returned concrete. Exemplary methods involve the use of an aggregate-forming inducer that provides a surface anchoring site for cement paste to bond/adhere, such as shredded news print, cardboard, or mixtures thereof, and also including fiber materials such as polymers, glass, and other material fibers. The aggregate-forming inducer is mixed with fresh concrete until aggregates are formed.

Method and composition for producing aggregates from cement and concrete, including residual or returned concrete. Exemplary methods involve the use of an aggregate-forming inducer that provides a surface anchoring site for cement paste to bond/adhere, such as shredded news print, cardboard, or mixtures thereof, and also including fiber materials such as polymers, glass, and other material fibers. The aggregate-forming inducer is mixed with fresh concrete until aggregates are formed.

Bentonite-based grout fluids and methods of using the grout fluids are provided. A method of using a grout fluid includes placing a geothermal conduit in at least one hole in the earth, providing a grout fluid consisting essentially of water and a bentonite-based grout, wherein the bentonite-based grout consists essentially of calcium carbonate, a bentonite, one or more grout-setting modifiers, and one or more thermally conductive materials, introducing the grout fluid into a space between the geothermal conduit and sidewalls of the at least one hole so that the grout fluid is in contact with the geothermal conduit, and after introducing the grout fluid, allowing the grout fluid to set to fix the geothermal conduit to the at least one hole, wherein after setting, the grout fluid has a hydraulic conductivity of between about 1×10.sup.−7 cm/s and about 1×10.sup.−9 cm/s.

Bentonite-based grout fluids and methods of using the grout fluids are provided. A method of using a grout fluid includes placing a geothermal conduit in at least one hole in the earth, providing a grout fluid consisting essentially of water and a bentonite-based grout, wherein the bentonite-based grout consists essentially of calcium carbonate, a bentonite, one or more grout-setting modifiers, and one or more thermally conductive materials, introducing the grout fluid into a space between the geothermal conduit and sidewalls of the at least one hole so that the grout fluid is in contact with the geothermal conduit, and after introducing the grout fluid, allowing the grout fluid to set to fix the geothermal conduit to the at least one hole, wherein after setting, the grout fluid has a hydraulic conductivity of between about 1×10.sup.−7 cm/s and about 1×10.sup.−9 cm/s.

A method for preparing an accelerator for sprayed mortar/concrete is provided. The accelerator includes an organic component, inorganic component aluminum sulfate, an initiator, and a reductant. The organic component in the form of a polymer monomer is added to concrete and polymerized into a polymer network structure in the presence of the initiator and the reductant; and the inorganic component aluminum sulfate promotes rapid hydration of the concrete to form an inorganic network structure. Such organic-inorganic interpenetrating network thickens a cement-based material rapidly to achieve strong adhesion, fast-setting and hardening properties and effectively reduces resilience of the sprayed mortar/concrete. The accelerator prepared by the method is well compatible with all sorts of cement, efficient and environmentally friendly. The organic-inorganic interpenetrating network is formed by polymerization and cement hydration, and therefore, the toughness of the sprayed mortar/concrete is improved by the organic polymer-inorganic compound accelerator.

A method for preparing an accelerator for sprayed mortar/concrete is provided. The accelerator includes an organic component, inorganic component aluminum sulfate, an initiator, and a reductant. The organic component in the form of a polymer monomer is added to concrete and polymerized into a polymer network structure in the presence of the initiator and the reductant; and the inorganic component aluminum sulfate promotes rapid hydration of the concrete to form an inorganic network structure. Such organic-inorganic interpenetrating network thickens a cement-based material rapidly to achieve strong adhesion, fast-setting and hardening properties and effectively reduces resilience of the sprayed mortar/concrete. The accelerator prepared by the method is well compatible with all sorts of cement, efficient and environmentally friendly. The organic-inorganic interpenetrating network is formed by polymerization and cement hydration, and therefore, the toughness of the sprayed mortar/concrete is improved by the organic polymer-inorganic compound accelerator.

A dry mineral binder composition includes cement and mineral fillers for the manufacture of molded parts by way of 3D printing. The binder composition additionally contains at least one aluminum sulfate-based accelerator, at least one polycarboxylate ether-based super-plasticizer and at least one rheology additive.