Systems for accelerated carbonation curing of a pre-cast cementitious structure may include an ejector and a curing chamber downstream of the ejector. The ejector may be operable to combine a lesser-pressure carbon dioxide containing stream from a carbon dioxide source with a greater-pressure steam to produce a mixed stream including at least steam and carbon dioxide. The mixed stream may have a pressure greater than the pressure of the lesser-pressure carbon dioxide containing stream. The curing chamber may be operable to receive the mixed stream from the ejector and contact the mixed stream with the pre-cast cementitious structure to cure the pre-cast cementitious structure. Processes for accelerated carbonation curing of pre-cast cementitious structures using the systems are also disclosed.

Synthetic pozzolans are produced using local materials to provide a cementitious material that is uniform in chemistry and properties independent of the location where the materials are obtained. Two methods of production are described. One is a high temperature process in which materials are processed in a semi-molten or molten state. The second process is a low temperature aqueous process.

The invention provides novel methods and compositions that mitigate the occurrence of hazing of products made from carbonatable calcium silicate-based cements. The methods and compositions of the invention may be applied in a variety of cement and concrete components in the infrastructure, construction, pavement and landscaping industries.

The invention provides novel methods and compositions that mitigate the occurrence of hazing of products made from carbonatable calcium silicate-based cements. The methods and compositions of the invention may be applied in a variety of cement and concrete components in the infrastructure, construction, pavement and landscaping industries.

A sulfate-resistant cement composition may contain calcium magnesium aluminum oxide silicate, brownmillerite, dolomite, periclase, and calcium aluminum oxide. The composition may contain the calcium aluminum oxide in an amount in the range of 0.01 to 2.0 wt. %. The composition may contain the brownmillerite in an amount of the range of 20 to 30 wt. %.

A sulfate-resistant cement composition may contain calcium magnesium aluminum oxide silicate, brownmillerite, dolomite, periclase, and calcium aluminum oxide. The composition may contain the calcium aluminum oxide in an amount in the range of 0.01 to 2.0 wt. %. The composition may contain the brownmillerite in an amount of the range of 20 to 30 wt. %.

The invention is a system and method for building a polar zonohedron structure from precast cement panels. The building system may include a plurality of panels configured to register with each other. Each panel includes a precast cement base with side walls enclosing a cavity within the precast cement base. The panels include at least one ridge protruding from at least one surface of a side wall of the panel and at least one aperture on at least one surface of a side wall of the panel. Each ridge is preferable configured to interlock with each aperture; in his way, the panels interlock with each other to form the polar zonohedron structure.

A method of cementing an annular space between a pipe string and a well bore, the method comprising the steps of (a) providing a cement composition including a calcium-deficient calcium silicate; (b) mixing the cement composition with water to form a cement slurry; (c) mixing the cement slurry composition with carbon dioxide form a foamed cement; and (d) placing the foamed cement in the annular space between the pipe string and the wellbore.

A method of cementing an annular space between a pipe string and a well bore, the method comprising the steps of (a) providing a cement composition including a calcium-deficient calcium silicate; (b) mixing the cement composition with water to form a cement slurry; (c) mixing the cement slurry composition with carbon dioxide form a foamed cement; and (d) placing the foamed cement in the annular space between the pipe string and the wellbore.

The invention provides novel methods and novel additive compositions and use thereof in a wide range of concrete production for improving properties of concrete materials, such as durability and aestheticity. The methods and compositions of the invention may be applied in a variety of cement and concrete components in the infrastructure, construction, pavement and landscaping industries.