A light weight geopolymer concrete, having a specific gravity less than 2.0, more typically between 1 and 1.3, is provided that has compressive strength comparable to or greater than ordinary Portland concrete. The light weight geopolymer concrete has low shrinkage, expansion, and cracking, and substantially no loss of compressive strength when exposed to high temperatures of 800° C. or greater, as would occur in a fire. To be useful as a load bearing member for general applications, such as residential housing, the compressive strength of the light-weight geopolymer concrete should be at least 10 MPa, preferably greater than 12 MPa, for example greater than 15 MPa. For more demanding uses, the compressive strength should be near or at the compressive strength of concrete, that is, greater than 20 MPa, preferably greater than 30 MPa, and optimally greater than 35 MPa. To be useful during and after a fire, the strength must not be reduced by more than 20%, preferably not less than 10%, optimally not reduced at all when exposed to heat up to 800° C. Embodiments of the invention include low-density high-temperature-resistant geopolymer concrete which increases load bearing strength when exposed to temperatures above 400° C., preferably at 800° C. Key constituents for forming most embodiments include a geopolymer source such as fly ash, a cement-coated expanded vermiculite, a fiber such as wollastonite, and soluble silicates such as alkali silicates.

A light weight geopolymer concrete, having a specific gravity less than 2.0, more typically between 1 and 1.3, is provided that has compressive strength comparable to or greater than ordinary Portland concrete. The light weight geopolymer concrete has low shrinkage, expansion, and cracking, and substantially no loss of compressive strength when exposed to high temperatures of 800° C. or greater, as would occur in a fire. To be useful as a load bearing member for general applications, such as residential housing, the compressive strength of the light-weight geopolymer concrete should be at least 10 MPa, preferably greater than 12 MPa, for example greater than 15 MPa. For more demanding uses, the compressive strength should be near or at the compressive strength of concrete, that is, greater than 20 MPa, preferably greater than 30 MPa, and optimally greater than 35 MPa. To be useful during and after a fire, the strength must not be reduced by more than 20%, preferably not less than 10%, optimally not reduced at all when exposed to heat up to 800° C. Embodiments of the invention include low-density high-temperature-resistant geopolymer concrete which increases load bearing strength when exposed to temperatures above 400° C., preferably at 800° C. Key constituents for forming most embodiments include a geopolymer source such as fly ash, a cement-coated expanded vermiculite, a fiber such as wollastonite, and soluble silicates such as alkali silicates.

A cement composition for application to a ceramic substrate, such as a cement skin composition for application to a ceramic honeycomb body is provided. The cement composition includes a first source of inorganic particles having a mean particle diameter <50 nm, wherein the first source of inorganic particles is present at about <15% (by dry weight), a second source of inorganic particles having a mean particle diameter of from about 50 nm to about 700 nm, wherein the second source of inorganic particles is present at from about 5% to about 15% (by dry weight), and a water-soluble organic binder. An inorganic fibrous material can be present at about <15% (based on dry weight). The amount of at least one of the first source of inorganic particles or the inorganic fibrous material is greater than 0% (by dry weight).

A cement composition for application to a ceramic substrate, such as a cement skin composition for application to a ceramic honeycomb body is provided. The cement composition includes a first source of inorganic particles having a mean particle diameter <50 nm, wherein the first source of inorganic particles is present at about <15% (by dry weight), a second source of inorganic particles having a mean particle diameter of from about 50 nm to about 700 nm, wherein the second source of inorganic particles is present at from about 5% to about 15% (by dry weight), and a water-soluble organic binder. An inorganic fibrous material can be present at about <15% (based on dry weight). The amount of at least one of the first source of inorganic particles or the inorganic fibrous material is greater than 0% (by dry weight).

The present invention relates to inorganic fibres having a composition comprising: 61.0 to 70.8 wt % SiO.sub.2; 28.0 to 39.0 wt % CaO; 0.10 to 0.85 wt % MgO other components, if any, providing the balance up to 100 wt %,

The sum of SiO.sub.2 and CaO is greater than or equal to 98.8 wt % and the other components comprise less than 0.70 wt % Al.sub.2O.sub.3, if any.

The present invention relates to inorganic fibres having a composition comprising: 61.0 to 70.8 wt % SiO.sub.2; 28.0 to 39.0 wt % CaO; 0.10 to 0.85 wt % MgO other components, if any, providing the balance up to 100 wt %,

The sum of SiO.sub.2 and CaO is greater than or equal to 98.8 wt % and the other components comprise less than 0.70 wt % Al.sub.2O.sub.3, if any.

Disclosed is a honeycomb support structure comprising a honeycomb body and an outer layer or skin formed of a cement that includes an inorganic filler material having a first coefficient of thermal expansion from 25° C. to 600° C. and a crystalline inorganic fibrous material having a second coefficient of thermal expansion from 25° C. to 600° C.

Disclosed is a honeycomb support structure comprising a honeycomb body and an outer layer or skin formed of a cement that includes an inorganic filler material having a first coefficient of thermal expansion from 25° C. to 600° C. and a crystalline inorganic fibrous material having a second coefficient of thermal expansion from 25° C. to 600° C.

The invention comprises a concrete form. The concrete form comprises a first panel having a first primary surface for contacting plastic concrete and a second primary surface opposite the first surface, wherein the first panel is made from a rigid plastic sheet or a metal sheet; and a second panel spaced from the second primary surface of the first panel, wherein the second panel is made from a rigid plastic sheet or a metal sheet. The concrete form also comprises a layer of insulating material disposed between the first panel and the second panel. A method of using the concrete form is also disclosed.

The invention comprises a concrete form. The concrete form comprises a first panel having a first primary surface for contacting plastic concrete and a second primary surface opposite the first surface, wherein the first panel is made from a rigid plastic sheet or a metal sheet; and a second panel spaced from the second primary surface of the first panel, wherein the second panel is made from a rigid plastic sheet or a metal sheet. The concrete form also comprises a layer of insulating material disposed between the first panel and the second panel. A method of using the concrete form is also disclosed.