A method of forming a cement composition. The method comprises adding to a hydraulic cementitious material a first strength-enhancing agent and a second strength-enhancing agent, wherein the content of total alkali (Na.sub.2O equivalent) in the hydraulic cementitious material is less than or equal to 0.7% by weight of the cementitious material. The first strength-enhancing agent includes a compound represented by structural formula (I): ##STR00001##
and
the second strength-enhancing agent is sodium sulfate, potassium sulfate, or a mixture thereof. The example values of the variables in structural formula (I) and the example amounts of the first and second strength-enhancing agents being added are defined herein.

An additive for mineral binder composition, in particular accelerators for mineral binder compositions, in particular cementitious binder compositions. The accelerator includes 35 to 99.7 w % of at least one mineral filler F with a particle size D50<5 μm, preferably <4 μm, most preferred <3.5 μm, 0.3 to 65 w % of a sodium aluminate SA, and 0 to 45 w % of at least one other inorganic compound I selected from the group consisting of calcium aluminate cements and/or sulfates of alkali or alkaline earth metals. Further, corresponding mineral binder compositions as well as uses and processes, including the acceleration of setting and curing of mineral binder compositions at low temperatures.

An additive for mineral binder composition, in particular accelerators for mineral binder compositions, in particular cementitious binder compositions. The accelerator includes 35 to 99.7 w % of at least one mineral filler F with a particle size D50<5 μm, preferably <4 μm, most preferred <3.5 μm, 0.3 to 65 w % of a sodium aluminate SA, and 0 to 45 w % of at least one other inorganic compound I selected from the group consisting of calcium aluminate cements and/or sulfates of alkali or alkaline earth metals. Further, corresponding mineral binder compositions as well as uses and processes, including the acceleration of setting and curing of mineral binder compositions at low temperatures.

Described are compositions and methods for controlled strength development in a hydratable cementitious material, and more particularly to the use of polymerizable monomer components, which are initiated and activated by a redox pair which are mixed in controlled fashion, for enhancing non-hydration strength within the matrix of the plastic hydratable cementitious material before setting of the cementitious material begins. Exemplary applications include minimizing pressures on formwork for high fluid ready-mix applications, enhancing support and bonding properties for integrated concrete slab work and other sequential applications, or facilitating speedy 3D printing applications, among other unique possibilities.

Described are compositions and methods for controlled strength development in a hydratable cementitious material, and more particularly to the use of polymerizable monomer components, which are initiated and activated by a redox pair which are mixed in controlled fashion, for enhancing non-hydration strength within the matrix of the plastic hydratable cementitious material before setting of the cementitious material begins. Exemplary applications include minimizing pressures on formwork for high fluid ready-mix applications, enhancing support and bonding properties for integrated concrete slab work and other sequential applications, or facilitating speedy 3D printing applications, among other unique possibilities.

A method of designing a cement slurry may include: (a) selecting at least a cement and concentration thereof, water and concentration thereof, and, optionally, at least one supplementary cementitious material and a concentration thereof, such that a cement slurry comprising the cement, the water, and, if present, the at least one supplementary cementitious material, meet a density requirement; (b) calculating a thickening time of the cement slurry using a thickening time model; (c) comparing the thickening time of the cement slurry to a thickening time requirement, wherein steps (a)-(c) are repeated if the thickening time of the cement slurry does not meet or exceed the thickening time requirement, wherein the selecting comprises selecting different concentrations and/or different chemical identities for the cement and/or the supplementary cementitious material than previously selected, or step (d) is performed if the thickening time of the cement slurry meets or exceeds the thickening time requirement; and preparing the cement slurry.

A method of designing a cement slurry may include: (a) selecting at least a cement and concentration thereof, water and concentration thereof, and, optionally, at least one supplementary cementitious material and a concentration thereof, such that a cement slurry comprising the cement, the water, and, if present, the at least one supplementary cementitious material, meet a density requirement; (b) calculating a thickening time of the cement slurry using a thickening time model; (c) comparing the thickening time of the cement slurry to a thickening time requirement, wherein steps (a)-(c) are repeated if the thickening time of the cement slurry does not meet or exceed the thickening time requirement, wherein the selecting comprises selecting different concentrations and/or different chemical identities for the cement and/or the supplementary cementitious material than previously selected, or step (d) is performed if the thickening time of the cement slurry meets or exceeds the thickening time requirement; and preparing the cement slurry.

A method of designing a cement slurry may include: (a) selecting at least a cement and concentration thereof, a water and concentration thereof, and one or more chemical additives and a concentration thereof such that a cement slurry formed from the cement, water, and the one or more chemical additives meet a density requirement; (b) calculating a thickening time of the cement slurry using a thickening time model; (c) comparing the thickening time of the cement slurry to a thickening time requirement, wherein steps (a)-(c) are repeated if the thickening time of the cement slurry does not meet or exceed the thickening time requirement, wherein the step of selecting comprises selecting concentrations and/or different chemical identities for the one or more chemical additives, cement, or water, or step (d) is performed if the thickening time of the cement slurry meets or exceeds the thickening time requirement; and (d) preparing the cement slurry.

A method of designing a cement slurry may include: (a) selecting at least a cement and concentration thereof, a water and concentration thereof, and one or more chemical additives and a concentration thereof such that a cement slurry formed from the cement, water, and the one or more chemical additives meet a density requirement; (b) calculating a thickening time of the cement slurry using a thickening time model; (c) comparing the thickening time of the cement slurry to a thickening time requirement, wherein steps (a)-(c) are repeated if the thickening time of the cement slurry does not meet or exceed the thickening time requirement, wherein the step of selecting comprises selecting concentrations and/or different chemical identities for the one or more chemical additives, cement, or water, or step (d) is performed if the thickening time of the cement slurry meets or exceeds the thickening time requirement; and (d) preparing the cement slurry.

A multi-component mortar system including a component A and a component B wherein, component A includes aluminous cement, at least one set inhibitor, at least one mineral filler and water, and component B includes an initiator system for the set-inhibited aluminous cement, at least one mineral filler and water. The multi-component mortar system is easy to use and suitable for repair and refurbishment and particularly for printing 3D structures.