Methods, systems, and apparatus, for performing additive manufacturing with concrete. One example is an additive manufacturing print head. The print head includes a body defining an internal flow path, a print nozzle at an outlet of the internal flow path, an auger disposed within the internal flow path, a first microwave emitter, and a second microwave emitter. The auger is operable to convey a concrete mixture towards the print nozzle. The first microwave emitter is operable to alter a viscosity of the concrete moisture within the flow path by directing first microwave energy towards the internal flow path. The second microwave emitter is arranged to direct second microwave energy towards the concrete mixture when it exits the print nozzle.

Methods, systems, and apparatus, for performing pultrusion molding with concrete. One exemplary method includes conveying a textile material through a concrete infusion system to provide a concrete infused textile material (CITM). Heating and shaping the CITM by conveying the CITM through a microwave chamber comprising an electrically non-conductive die disposed therein, the microwave chamber operable to heat concrete infused in the textile material by irradiating the CITM with microwave energy as the CITM is conveyed through the microwave chamber, and the die operable to shape the CITM as the CITM is conveyed through the microwave chamber. Cooling the CITM by conveying the CITM through a cool down chamber operable to maintain heat in the CITM as the CITM is conveyed through the microwave chamber allowing the concrete to cure while a temperature of the CITM is reduced.

A cementitious print head and a cementitious printing methodology may include a feed barrel, a print head nozzle, a CO.sub.2 supply, a steam supply, a selective valve assembly in communication with the CO.sub.2 supply and the steam supply, a plurality of dual use extrusion head injectors, and a print head controller. The print head controller is operatively coupled to the selective valve assembly and is programmed to execute a CO.sub.2 and steam injection protocol where steam may be selected for injection by the extrusion head injectors into a cementitious composition as it is extruded from the print head nozzle to enhance a hydration reaction and formation of hydroxide in the cementitious composition before CO.sub.2 may be selected for injection by the extrusion head injectors into the cementitious composition as it is extruded from the print head nozzle to enhance a carbonation reaction in the cementitious composition.

A cement-based tile formed from a mixture comprising: a cement in the range of about 0.1 to 88% by wet weight percent; a secondary material in the range of about 0.1 to 50% by wet weight percent, the secondary material comprising limestone, sand, silica sand, gypsum, silica fume, fumed silica, Plaster of Paris, calcium carbonate, fly ash, slag, rock, or a combination thereof; a reinforcement fiber in the range of about 0.5 to 20% by wet weight percent, the reinforcement fiber comprising cellulose fiber, glass fiber, plastic fiber, polypropylene fiber, polyvinyl alcohol (PVA) fiber, homopolymer acrylic fiber, alkali-resistant fiber, or a combination thereof; a rheology modifying agent in the range of about 0.5 to 10% by wet weight percent; a water in the range of 10 to 60% of a total wet material weight; and wherein the mixture is extruded or molded to form the cement-based tile.

A cement-based tile formed from a mixture comprising: a cement in the range of about 0.1 to 88% by wet weight percent; a secondary material in the range of about 0.1 to 50% by wet weight percent, the secondary material comprising limestone, sand, silica sand, gypsum, silica fume, fumed silica, Plaster of Paris, calcium carbonate, fly ash, slag, rock, or a combination thereof; a reinforcement fiber in the range of about 0.5 to 20% by wet weight percent, the reinforcement fiber comprising cellulose fiber, glass fiber, plastic fiber, polypropylene fiber, polyvinyl alcohol (PVA) fiber, homopolymer acrylic fiber, alkali-resistant fiber, or a combination thereof; a rheology modifying agent in the range of about 0.5 to 10% by wet weight percent; a water in the range of 10 to 60% of a total wet material weight; and wherein the mixture is extruded or molded to form the cement-based tile.

The present description relates to a method of producing a wet-cast slag-based concrete product particularly where the wet-cast slag-based concrete product is partially or completely set inside a mould, pre-conditioned outside of the mould and then cured with carbon dioxide in a curing chamber. The wet-cast slag-based concrete product is optionally reinforced.

A manufacturing process of a cement product includes: (a) reacting at least one anhydrous or hydrated cement component with liquid or supercritical CO.sub.2 to form a cement composition; and (b) curing the cement composition to form a cement product.

The invention provides novel apparatus and processes for gas flow and conditioning to achieve optimal CO.sub.2 curing of articles of composite materials (e.g., precast objects made of carbonatable calcium silicate-based cements), with solid interior or having hollow interior ducts, channels and chambers or otherwise being hollowed out, as well as the precast objects so made, which are suitable for a variety of applications in construction, pavements and landscaping, and infrastructure.

The present description relates to methods of producing a wet-cast slag-based concrete product particularly where the wet-cast slag-based concrete product is cast, pre-conditioned and cured with carbon dioxide inside a mould and/or inside a mould placed in a curing chamber. The wet-cast slag-based concrete product is optionally reinforced.

A cementitious print head and a cementitious printing methodology may include a feed barrel, a print head nozzle, a CO.sub.2 supply, a steam supply, a selective valve assembly in communication with the CO.sub.2 supply and the steam supply, a plurality of dual use extrusion head injectors, and a print head controller. The print head controller is operatively coupled to the selective valve assembly and is programmed to execute a CO.sub.2 and steam injection protocol where steam may be selected for injection by the extrusion head injectors into a cementitious composition as it is extruded from the print head nozzle to enhance a hydration reaction and formation of hydroxide in the cementitious composition before CO.sub.2 may be selected for injection by the extrusion head injectors into the cementitious composition as it is extruded from the print head nozzle to enhance a carbonation reaction in the cementitious composition.