A method for manufacturing hydraulically hardening building materials, includes the steps of: providing concrete demolition waste with a maximum particle size of up to 150 mm as a starting material, mixing the starting material with water to form a feedstock slurry, introducing carbon dioxide or a precursor thereof into the feedstock slurry to form carbonated concrete fines in an amount from 1 to 100 wt.-% of the hardened binder contained in the starting material and to detach the concrete fines from the aggregate contained in the starting material to form a product slurry, and mixing the product slurry with a cement forming the building material, and use of the obtainable building material for manufacturing building structures as well as method for manufacturing a supplementary cementitious material slurry.

The present invention discloses an optimized preparation method of a carbonization-based lightweight CO.sub.2 foamed cement-based material, and belongs to the field of geotechnical engineering materials. The preparation method includes: step S1: pre-screening existing common cement-based foaming agents and foam stabilizers; step S2: preparing a water-based carbon dioxide foam; step S3: preparing a cement slurry, and mixing the water-based carbon dioxide foam with the cement slurry to prepare a lightweight CO.sub.2 foamed cement-based material; step S4: selecting foaming agents of different types and different concentrations and foam stabilizers of different types and different concentrations to prepare slurries, subjecting the slurries to slurry performance tests, and selecting the optimal ones; step S5: optimizing initial water-to-cement ratio and foam-to-slurry ratio parameters; and step S6: optimizing a gas-filling volume parameter (water pump speed).

An apparatus (100) for the production of a plaster slurry is described, the apparatus (100) comprising a mixer (102) for mixing at least plaster and water to form a plaster slurry, the mixer (102) comprising an outlet conduit (122), a foam generator (106) for mixing at least air, a foaming agent and water to produce a foam, the foam generator (106) in fluid communication with the mixer (102) via a fluid pathway (116) comprising a foam conduit (117); and a mass flow meter (124), wherein the mass flow meter (124) is configured to measure the density and mass flow rate of the foam within the foam conduit (117) or the plaster slurry within the outlet conduit (122). Additionally, a method of manufacturing a plaster slurry is described.

A system and method for disposing carbon dioxide is disclosed. The system includes a foam generator that generates a plurality of disposable foam vessels from a polymer based solution mixed with water and captured carbon dioxide from the atmosphere. The plurality of disposable foam vessels contains an amount of carbon dioxide. The plurality of disposable foam vessels is mixed in a cementitious material with a set of mixers. In a preferred embodiment, the set of mixers is a concrete mixing plant. During the curing process of the cementitious material the plurality of disposable foam vessels dissipates allowing for a timely release of CO.sub.2 to chemically react with the surrounding cementitious material. This irreversible chemistry change permanently disposes of the carbon dioxide.

Provided herein are methods and compositions for carbonation of recycled concrete aggregates (RCA) to produce carbonated RCA. In addition, uses of the carbonated RCA, such as in building materials, and building materials containing RCA, are included. Carbonation of RCA may be used alone or may be used in combination with other carbonation processes associated with concrete manufacture, such as carbonation of wet concrete mixes and/or carbonation of concrete wash water.

Systems and methods of sequestering carbon dioxide in concrete are described herein. The methods include combining water and a foaming agent to form a foaming agent mixture, adding a gas comprising carbon dioxide to the foaming agent mixture in a first mixing chamber, mixing the water, the gas comprising carbon dioxide and the foaming agent to form a foam mixture in the first mixing chamber, the foam mixture comprising a plurality of foam bubbles containing the at least a portion of the carbon dioxide, combining the foam mixture with concrete materials in a second mixing chamber so that the foam mixture contacts the concrete materials, the concrete materials comprising cement, and mixing the foam mixture and the concrete materials in the second mixing chamber to form the concrete having the carbon dioxide sequestered therein.

Cellular concrete is formed from a cement-based wet mix slurry with a foam entrained into the wet mix. The foam is created using a foaming agent, mixed with water and air using a foam generator. The wet mix is mixed with the foam to form the cellular concrete wet mix. Poor component metering and blending practices in the current state of the art limits the performance capabilities of existing cellular concrete placements. The presently disclosed technology addresses this with a cellular concrete mixing system comprising a dry mix hopper to store a quantity of dry mix, a mixing tank to blend the dry mix and water together to form a wet mix, a holding tank to store a quantity of the wet mix, a foam generator to generate foam from air, water, and foam concentrate, and a blend controller to control operation of the overall mixing system.

A method for the manufacture of foamed plaster utilizing a mixture of powdered casting plaster, powdered limestone and hemp fibre. The mixture is fed into a Venturi apparatus (40) under the influence of gravity. Compressed air may be supplied to the Venturi apparatus (40) through an inlet pipe (41) causing air and solid particles to be sucked into the Venturi apparatus (40). The elongated tube is provided with an inlet nozzle arranged to receive a mixture of water mixed with detergent agents. Further, the tube (50) is provided with an inlet nozzle (56) arranged to receive compressed air such that the elongated tube (50) delivers the mixture to a mixing and spray head (60) so as to feed the resulting mixture to a moulding means.

The invention relates to an apparatus (110) for producing foamed building materials, comprising a gas supply unit (112), a suspension supply unit (150-156), and a mixing chamber (118), the apparatus (110) further comprising a control and/or regulating unit (136) which has means (116, 124, 130, 134, 146,) for supplying values of a plurality of input parameters, based on which at least a temperature of the dispersion and an air pressure in an environment of the apparatus (110) can be inferred, the control and/or regulating unit (136) being further configured to influence at least one output parameter, by means of which the ratio of the volumes and/or masses and/or densities of gas and suspension supplied per unit of time can be adjusted. The invention further relates to a corresponding method.

Manufactures, methods and apparatus are provided through which in some implementations a structural cellular lightweight concrete comprises a concrete mixture that is no more than 65% by volume of the manufacture of structural cellular lightweight concrete, the concrete mixture including concrete conforming to the requirements of ASTM C33; foam that has a density of at least 5 lbs/ft.sup.3, having high stability characteristics, and having a closed cell bubble structure; mix water being potable and free of contamination or deleterious materials; and Portland cement conforming to ASTM C150, the Portland cement being Type I, Type III or White Portland cement, and at least 35% air by volume of the manufacture of structural cellular lightweight concrete.