The invention provides novel aerated composite materials made from a carbonatable calcium silicate composition, and formulations and methods of manufacture and use thereof, in particular, the use of novel additive mineral compositions in the form of magnesium, magnesium salts or magnesium oxides, to improve physical chemical properties of low density concrete materials. The low density, aerated material is comprised of calcium carbonate (CaCO.sub.3) and silica (SiO.sub.2), as cured products of carbonatable calcium silicate compositions.

The present disclosure relates to a medical cement composition containing calcium silicate in an amount of less than 20 wt % of a total weight of the composition, with a lithium salt being added thereto. The medical cement composition of the present disclosure has a low compressive strength of 12 MPa or less, after being hardened, for easy removal, excellent stability in storage, and high bioactivity.

The present disclosure relates to a medical cement composition containing calcium silicate in an amount of less than 20 wt % of a total weight of the composition, with a lithium salt being added thereto. The medical cement composition of the present disclosure has a low compressive strength of 12 MPa or less, after being hardened, for easy removal, excellent stability in storage, and high bioactivity.

The invention provides novel paving stones and construction block composite materials and methods for preparation thereof. The paving stones and construction block composite materials can be readily produced from widely available, low cost precursor materials by a production process that involves compacting in a mold that is suitable for large-scale production. The precursor materials include calcium silicate, for example, wollastonite, and particulate filler materials which can comprise silicon dioxide-rich materials. Additives can include calcium carbonate-rich and magnesium carbonate-rich materials. Various additives can be used to fine-tune the physical appearance and mechanical properties of the composite material, such as colorants such as particles of colored materials, such as, and pigments (e.g., black iron oxide, cobalt oxide and chromium oxide). These paving stones and construction block composite materials exhibit visual patterns similar to stone as well as display compressive strength and water absorption equal to or better than that of stone.

The invention provides novel paving stones and construction block composite materials and methods for preparation thereof. The paving stones and construction block composite materials can be readily produced from widely available, low cost precursor materials by a production process that involves compacting in a mold that is suitable for large-scale production. The precursor materials include calcium silicate, for example, wollastonite, and particulate filler materials which can comprise silicon dioxide-rich materials. Additives can include calcium carbonate-rich and magnesium carbonate-rich materials. Various additives can be used to fine-tune the physical appearance and mechanical properties of the composite material, such as colorants such as particles of colored materials, such as, and pigments (e.g., black iron oxide, cobalt oxide and chromium oxide). These paving stones and construction block composite materials exhibit visual patterns similar to stone as well as display compressive strength and water absorption equal to or better than that of stone.

Disclosed are cementitious materials as well as methods of forming cured cementitious materials. In one aspect, provided are methods of forming a cured cementitious material that comprise (a) contacting a cementitious material comprising a calcium silicate precursor with water and carbon dioxide under conditions effective to form crystalline’calcium silicate hydrates within the cementitious material; and (b) allowing the cementitious material to harden to form the cured cementitious material.

Disclosed are cementitious materials as well as methods of forming cured cementitious materials. In one aspect, provided are methods of forming a cured cementitious material that comprise (a) contacting a cementitious material comprising a calcium silicate precursor with water and carbon dioxide under conditions effective to form crystalline’calcium silicate hydrates within the cementitious material; and (b) allowing the cementitious material to harden to form the cured cementitious material.

A cement composition including a hydraulic cement material, a latent-hydraulic cement material, and a non-hydraulic cement material. Also provided is a method including combining, at a jobsite, the cement composition comprising the hydraulic cement material, the latent-hydraulic cement material, and the non-hydraulic cement material with water to provide a cement slurry, and allowing the cement slurry to harden in the presence of carbon dioxide (CO.sub.2) to provide a hardened cement.

A cement composition including a hydraulic cement material, a latent-hydraulic cement material, and a non-hydraulic cement material. Also provided is a method including combining, at a jobsite, the cement composition comprising the hydraulic cement material, the latent-hydraulic cement material, and the non-hydraulic cement material with water to provide a cement slurry, and allowing the cement slurry to harden in the presence of carbon dioxide (CO.sub.2) to provide a hardened cement.

The invention discloses an artificial nacre material with layered structure and preparation method thereof. The preparation method includes the following steps: uniformly mixing a carbonated cementitious material and water at a water-solid ratio of 0.3 to 1.2 to obtain a carbonated cementitious material suspension; treating the carbonated cementitious material suspension by a freeze-casting process to obtain a carbonated cementitious material coagulation with layered structure; treating the carbonated cementitious material coagulation with the layered structure by a freeze-drying process to obtain a carbonated cementitious material with layered structure; treating the carbonated cementitious material with layered structure by a carbonization process to obtain an artificial nacre material with layered structure. The obtained artificial nacre material with layered structure has higher fracture toughness and durability, and the preparation method has the advantages of low energy consumption, carbon dioxide fixation and environmental friendliness.