A method for the production of a cavity filled with a low-density mineral foam includes (i) preparing a cement slurry including Portland cement; ultrafine particles of which the D50 is from 10 to 600 nm; a water reducing agent; a manganese salt; and water; wherein the mass ratio of manganese salts/Portland cement is below 0.014; (ii) adding to the cement slurry obtained after (i) a gas-forming liquid including a gas-forming agent; and a viscosity-modifying agent which is a polymer chosen among anionic bio-based polymer, amphiphilic bio-based polymer, alkali swellable acrylic polymer and mixture thereof; to obtain a foaming slurry; (iii) filling the cavity with the foaming slurry obtained at (ii); (iv) leaving the foaming slurry to expand within the cavity.

The present invention relates to a new class of chemical admixtures for hydraulic cement compositions and methods of preparing same. The admixtures, which include complexes of metals with one or more hydroxycarboxylic acids and/or derivatives of hydroxycarboxylic acids, improve at least the following properties of cement compositions: hardness, compressive strength, shrinkage, and freeze-thaw resistance. Hydraulic cement compositions that may be improved with the chemical admixtures include pastes, mortars, grouts and concretes, all of which may be made from ordinary Portland cement, blended cements, or non-Portland cements made with Supplementary Cementitious Materials.

The present invention relates to a new class of chemical admixtures for hydraulic cement compositions and methods of preparing same. The admixtures, which include complexes of metals with one or more hydroxycarboxylic acids and/or derivatives of hydroxycarboxylic acids, improve at least the following properties of cement compositions: hardness, compressive strength, shrinkage, and freeze-thaw resistance. Hydraulic cement compositions that may be improved with the chemical admixtures include pastes, mortars, grouts and concretes, all of which may be made from ordinary Portland cement, blended cements, or non-Portland cements made with Supplementary Cementitious Materials.

Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets and low density fillers distributed throughout. The combination of entrained air pockets and low density fillers provide a low density fiber cement matrix with physical and mechanical properties similar to comparable low density fiber cement matrix without entrained air pockets.

Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets and low density fillers distributed throughout. The combination of entrained air pockets and low density fillers provide a low density fiber cement matrix with physical and mechanical properties similar to comparable low density fiber cement matrix without entrained air pockets.

An object to provide a prestressed concrete that can be widely used for general building members, in which a chemical stress induced by an expansive material and a mechanical stress induced by a continuous fiber reinforcing wire are simultaneously used together, and due to a synergistic effect of the mechanical stress and the chemical stress, the strength is increased, the reduction in weight, reduction in thickness, and suppression of cracking are achieved, and the degree of freedom in design increased. To provide a prestressed concrete characterized in that, in a concrete into which a prestress is introduced, a mechanical stress induced by a tensional material and a chemical stress induced by an expansive material for a concrete are introduced simultaneously into the concrete, the tensional material is a continuous fiber reinforcing wire, the expansive material for a concrete is contained in an amount of 5 to 30 kg/m3, and aluminum oxide contained in an amount of 0.2 to 2.0% by weight to the expansive material.

An object to provide a prestressed concrete that can be widely used for general building members, in which a chemical stress induced by an expansive material and a mechanical stress induced by a continuous fiber reinforcing wire are simultaneously used together, and due to a synergistic effect of the mechanical stress and the chemical stress, the strength is increased, the reduction in weight, reduction in thickness, and suppression of cracking are achieved, and the degree of freedom in design increased. To provide a prestressed concrete characterized in that, in a concrete into which a prestress is introduced, a mechanical stress induced by a tensional material and a chemical stress induced by an expansive material for a concrete are introduced simultaneously into the concrete, the tensional material is a continuous fiber reinforcing wire, the expansive material for a concrete is contained in an amount of 5 to 30 kg/m3, and aluminum oxide contained in an amount of 0.2 to 2.0% by weight to the expansive material.

The present disclosure relates to the field of ecological restoration of a coal gangue hill, and in particular, to a solid waste-based porous material, a method for preparing the solid waste-based porous material, and a method of ecological restoration of the coal gangue hill by applying the solid waste-based porous material. A coal-based solid waste restoration material and mycorrhizal solid bacterial agent are mixed to restore the coal gangue hill, the coal-based solid waste restoration material is prepared by mixing coal-based solid waste porous materials, low-rank coal, and waste organic matter and adding a microbial quickly decomposition agent for aerobic fermentation and standing.

The present disclosure relates to the field of ecological restoration of a coal gangue hill, and in particular, to a solid waste-based porous material, a method for preparing the solid waste-based porous material, and a method of ecological restoration of the coal gangue hill by applying the solid waste-based porous material. A coal-based solid waste restoration material and mycorrhizal solid bacterial agent are mixed to restore the coal gangue hill, the coal-based solid waste restoration material is prepared by mixing coal-based solid waste porous materials, low-rank coal, and waste organic matter and adding a microbial quickly decomposition agent for aerobic fermentation and standing.

A system and associated methods for processing unhardened concrete are disclosed. It at least one embodiment, the system for processing unhardened concrete includes a means to estimate a quantity of returned concrete; a foam adder to add foam to the quantity of returned concrete; a mixer to mix the added foam and returned concrete together to create treated concrete; a discharger to discharge the treated concrete; a discharge area configured in which to allow the treated concrete to set and harden; a converter to convert the hardened treated concrete into a particulate or aggregate form; and a user to determine the specific utilization of the particulate or aggregate form loose material.