Foundry casting elements and methods of forming the same, the methods including: forming an aqueous slurry including an inorganic binder precursor, shaping the slurry using a pattern, curing the shaped slurry using a low temperature solidification process to form a casting element, and removing the pattern from the casting element.

Foundry casting elements and methods of forming the same, the methods including: forming an aqueous slurry including an inorganic binder precursor, shaping the slurry using a pattern, curing the shaped slurry using a low temperature solidification process to form a casting element, and removing the pattern from the casting element.

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).

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).

The present invention primarily relates to the use of a mixture capable of biocementation as a means of preventing or reducing plant growth, preferably weed growth. The invention also relates to a method for preventing or reducing plant growth, preferably weed growth, on/in a substrate.

The present invention primarily relates to the use of a mixture capable of biocementation as a means of preventing or reducing plant growth, preferably weed growth. The invention also relates to a method for preventing or reducing plant growth, preferably weed growth, on/in a substrate.

Method and equipment for conditioning wet concrete (703), the wet concrete (703) being agitated in a revolving-drum concrete mixer (702), thereby bringing changing portions of the wet concrete (703) to a free surface (706) of the wet concrete (703) inside the mixer (702), the agitated wet concrete (703) being cooled and partially carbonated in that liquid and/or solid carbon dioxide is supplied to the concrete mixer (702) simultaneously with liquid nitrogen so that both the supplied nitrogen and the supplied carbon dioxide contact the free surface (706) of the wet concrete (703).

Method and equipment for conditioning wet concrete (703), the wet concrete (703) being agitated in a revolving-drum concrete mixer (702), thereby bringing changing portions of the wet concrete (703) to a free surface (706) of the wet concrete (703) inside the mixer (702), the agitated wet concrete (703) being cooled and partially carbonated in that liquid and/or solid carbon dioxide is supplied to the concrete mixer (702) simultaneously with liquid nitrogen so that both the supplied nitrogen and the supplied carbon dioxide contact the free surface (706) of the wet concrete (703).

The method for producing a carbonate bonded, compacted article, which method comprises the steps of providing a particulate, carbonatable material; compacting the particulate material to form a compact; and carbonating said compact. The carbonation of the compact is started and subsequently continued for at least 1 hour with a low partial carbon dioxide pressure in the carbonation gas which is lower than 0.5 bars, after which carbonation of the compact is continued for at least 8 hours with a high partial carbon dioxide pressure in the carbonation gas which is higher than 0.5 bars. By carbonating in two phases with a low and a high partial carbon dioxide pressure, a higher compressive strength of the carbonated compacts can be achieved within a predetermined carbonation time, in particular within a carbonation time of about 24 hours so that every day new compacts can be carbonated.

The method for producing a carbonate bonded, compacted article, which method comprises the steps of providing a particulate, carbonatable material; compacting the particulate material to form a compact; and carbonating said compact. The carbonation of the compact is started and subsequently continued for at least 1 hour with a low partial carbon dioxide pressure in the carbonation gas which is lower than 0.5 bars, after which carbonation of the compact is continued for at least 8 hours with a high partial carbon dioxide pressure in the carbonation gas which is higher than 0.5 bars. By carbonating in two phases with a low and a high partial carbon dioxide pressure, a higher compressive strength of the carbonated compacts can be achieved within a predetermined carbonation time, in particular within a carbonation time of about 24 hours so that every day new compacts can be carbonated.