The present invention relates to methods for the production of fresh cured fiber cement products. More particularly, the present invention provides methods for the production of fresh fiber cement products comprising cured fiber cement waste material, at least comprising the steps of: (a) Providing a cured fiber cement waste powder by comminuting cured fiber cement waste material; (b) Providing an aqueous fiber cement slurry comprising water, cementitious binder, natural or synthetic fibers and said cured fiber cement waste powder; (c) Forming a green fiber cement sheet from said aqueous fiber cement slurry; and (d) Autoclave-curing said green fiber cement sheet thereby providing a fresh fiber cement product.

The present invention relates to methods for the production of fresh cured fiber cement products. More particularly, the present invention provides methods for the production of fresh fiber cement products comprising cured fiber cement waste material, at least comprising the steps of: (a) Providing a cured fiber cement waste powder by comminuting cured fiber cement waste material; (b) Providing an aqueous fiber cement slurry comprising water, cementitious binder, natural or synthetic fibers and said cured fiber cement waste powder; (c) Forming a green fiber cement sheet from said aqueous fiber cement slurry; and (d) Autoclave-curing said green fiber cement sheet thereby providing a fresh fiber cement product.

The present invention provides means capable of imparting high temporal stability to a hardening aid solution which serves as a raw material and capable of imparting high strength and high quality stability to a hardened body of the self-hardening material, in the hardened body of the self-hardening material that contains a ceramic powder containing Si element at least on the surface thereof. The present invention relates to a hardening aid solution containing Si element, an alkali, and a dispersing medium, wherein the dispersing medium contains water; a dissolution concentration of the Si element is 20000 mass ppm or more; the number of moles of the alkali present in 1 kg of the dispersing medium is 2 mol/kg or more; an absolute value of an amount of change in a dissolution concentration of Si element in a solution obtained by diluting the hardening aid solution by 2 times based on the mass using an aqueous KOH solution having a concentration of 3 mol/L is 2000 mass ppm or less, between before and after a heat dissolution test including heating the solution at a solution temperature of 80° C. for 5 hours, and then allowing the solution to stand in an ambient environment at 25° C. for 1 hour; and the hardening aid solution is used for hardening a powder containing a ceramic powder containing Si element at least on the surface thereof.

The present invention provides means capable of imparting high temporal stability to a hardening aid solution which serves as a raw material and capable of imparting high strength and high quality stability to a hardened body of the self-hardening material, in the hardened body of the self-hardening material that contains a ceramic powder containing Si element at least on the surface thereof. The present invention relates to a hardening aid solution containing Si element, an alkali, and a dispersing medium, wherein the dispersing medium contains water; a dissolution concentration of the Si element is 20000 mass ppm or more; the number of moles of the alkali present in 1 kg of the dispersing medium is 2 mol/kg or more; an absolute value of an amount of change in a dissolution concentration of Si element in a solution obtained by diluting the hardening aid solution by 2 times based on the mass using an aqueous KOH solution having a concentration of 3 mol/L is 2000 mass ppm or less, between before and after a heat dissolution test including heating the solution at a solution temperature of 80° C. for 5 hours, and then allowing the solution to stand in an ambient environment at 25° C. for 1 hour; and the hardening aid solution is used for hardening a powder containing a ceramic powder containing Si element at least on the surface thereof.

This invention discloses a double-liquid grouting slurry, its technology and application for super large diameter underwater shield engineering under high water pressure condition. The materials of slurry I are: 35-45 parts of cement clinker; 15-25 parts of slag; 24-35 parts of fly ash; 15-25 parts of steel slag; 5-15 parts of bentonite; 4-10 parts of limestone tailing; 0.3-2.0 parts of water reducing agent; 0.5-2.5 parts of cellulose. The materials of slurry II are: 0.2-3.8 parts of short-cut fiber; 96-99 parts of sodium silicate solution; 0.8-4.8 parts of viscous polymers. This invention generates the double-liquid slurry preparation process including crushing-screening-milling-group mixing-grouped mixing at different speeds, the volume ratio of slurry I and II is 1:1-10:1 during grouting, and the slurry is injected into the shield void through the six-point position technology at the shield tail and 3+2+1 segment splicing synchronous grouting techniques.

A synchronous single-liquid grouting slurry, its technology and application for large diameter shield engineering under water-rich, high-pressure and weak soil strata conditions, comprising raw materials: 1050-1200 parts of gold tailing, 420-480 parts of silicate cement clinker, 220-240 parts of fly ash, 45-120 parts of waste clay brick, 65-95 parts of slag, 25-45 parts of limestone tailing, 70-80 parts of steel slag, 30-45 parts of silica fume, 15-22 parts of desulfurized gypsum, and 9-15 parts of quick-setting and early-strength composite additive. The invention controls the d.sub.50, d.sub.85 and d.sub.95 of the material particles as 35-40, 42-48 and 50-55 μm, respectively. Gold tailing with the particle size of 120-600 μm being used as the fine aggregate, their volume fractions are 40-60%. The slurry production technique, comprising crushing-sieving-superfine ball milling-homogenization-particle size classification-variable speed mixing being developed. The shield tail eight-point grouting technique is being developed for filling.

The present invention relates to additives and, more specifically, the use of biochar, in concrete and other cementitious materials to provide for building materials that have a lower carbon footprint than their traditional counterparts. Traditional methods for production of cement produce large amount of carbon dioxide (CO2). When coupled with the massive demand for cement building materials around the world, this means that the cement production has a significant impact on the amount of CO2 produced globally. By including biochar and other additives along with, or instead of some traditional components of cement, one may be able to provide for cementitious building materials that sequester carbon, rather than release it.

The present invention relates to additives and, more specifically, the use of biochar, in concrete and other cementitious materials to provide for building materials that have a lower carbon footprint than their traditional counterparts. Traditional methods for production of cement produce large amount of carbon dioxide (CO2). When coupled with the massive demand for cement building materials around the world, this means that the cement production has a significant impact on the amount of CO2 produced globally. By including biochar and other additives along with, or instead of some traditional components of cement, one may be able to provide for cementitious building materials that sequester carbon, rather than release it.

Provided are a textile reinforced cement composite for suppressing occurrence of slipping and a crack and a manufacturing method thereof. The textile reinforced cement composite for suppressing occurrence of slipping and a crack can suppress slipping between a textile grid reinforcement and a cement composite by using an angulated filling material mixed therewith when a textile reinforced cement composite having a textile grid reinforcement embedded in a cement composite is manufactured, suppress occurrence of a crack of the cement composite, suppress occurrence of a crack of the cement composite due to a fiber bridging reaction by using organic fiber mixed therewith, induce distribution of fine cracks, suppress degradation of fluidity of the cement composite caused by mixing of the angulated filling material by using a spherical binder and a chemical admixture added thereto, and suppress slipping between the textile grid reinforcement and the cement composite by using a fine powder binder having a predetermined particle size and mixed therewith.

Provided are a textile reinforced cement composite for suppressing occurrence of slipping and a crack and a manufacturing method thereof. The textile reinforced cement composite for suppressing occurrence of slipping and a crack can suppress slipping between a textile grid reinforcement and a cement composite by using an angulated filling material mixed therewith when a textile reinforced cement composite having a textile grid reinforcement embedded in a cement composite is manufactured, suppress occurrence of a crack of the cement composite, suppress occurrence of a crack of the cement composite due to a fiber bridging reaction by using organic fiber mixed therewith, induce distribution of fine cracks, suppress degradation of fluidity of the cement composite caused by mixing of the angulated filling material by using a spherical binder and a chemical admixture added thereto, and suppress slipping between the textile grid reinforcement and the cement composite by using a fine powder binder having a predetermined particle size and mixed therewith.