A method for producing a silica aerogel, the method including preparing a reactant by adding a basic catalyst to a first silica precursor solution, performing primary gelation in which the reactant is stirred to form a gel precursor, introducing a second silica precursor solution to a fiber, and performing a secondary gelation in which the gel precursor is introduced to the fiber to which the second silica precursor solution was introduced to form a silica aerogel.

A lightweight composite composition includes a plurality of lightweight particles including a volume of at least about 10% of a total volume of the lightweight composite composition. The plurality of lightweight particles includes an average bulk density within a range from about 0.001 g/cc to about 1.5 g/cc and an average particle size within a range from about 0.01 microns to about 90 mm. Methods of manufacturing a lightweight composite composition are provided.

A lightweight composite composition includes a plurality of lightweight particles including a volume of at least about 10% of a total volume of the lightweight composite composition. The plurality of lightweight particles includes an average bulk density within a range from about 0.001 g/cc to about 1.5 g/cc and an average particle size within a range from about 0.01 microns to about 90 mm. Methods of manufacturing a lightweight composite composition are provided.

A silica aerogel having a mean pore size less than 5 nm with a standard deviation of 3 nm. The silica aerogel may have greater than 95% solar-weighted transmittance at a thickness of 8 mm for wavelengths in the range of 250 nm to 2500 nm, and a 400 C. black-body weighted specific extinction coefficient of greater than 8 m.sup.2/kg for wavelengths of 1.5 m to 15 m. Silica aerogel synthesis methods are described. A solar thermal aerogel receiver (STAR) may include an opaque frame defining an opening, an aerogel layer disposed in the opaque frame, with at least a portion of the aerogel layer being proximate the opening, and a heat transfer fluid pipe in thermal contact with and proximate the aerogel layer. A concentrating solar energy system may include a STAR and at least one reflector to direct sunlight to an opening in the STAR.

Concrete compositions containing cement, a fine aggregate such as sand, a coarse aggregate such as crushed limestone, an industrial waste material such as electric arc furnace dust, cement kiln dust, oil ash, or limestone powder. High performance concretes made therefrom and methods of producing such concretes are also specified. The addition of industrial waste materials and nano silica provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to penetration of chloride ions) to the high performance concretes.

Concrete compositions containing cement, a fine aggregate such as sand, a coarse aggregate such as crushed limestone, an industrial waste material such as electric arc furnace dust, cement kiln dust, oil ash, or limestone powder. High performance concretes made therefrom and methods of producing such concretes are also specified. The addition of industrial waste materials and nano silica provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to penetration of chloride ions) to the high performance concretes.

A structure for protecting a substrate. The structure comprises an inner tie coat layer which can bond to the substrate, a geopolymer foam layer, and an outer protective layer. The geopolymer foam layer is the reaction product of a mixture comprising an aluminosilicate source, an alkali activator, reinforcing fibres, and a plurality of microparticles.

A structure for protecting a substrate. The structure comprises an inner tie coat layer which can bond to the substrate, a geopolymer foam layer, and an outer protective layer. The geopolymer foam layer is the reaction product of a mixture comprising an aluminosilicate source, an alkali activator, reinforcing fibres, and a plurality of microparticles.

A dispersion of an alkyd-containing polymer dispersed in water is used to form a waterborne coating composition; the alkyd-containing polymer being an acrylic-modified alkyd polymer, a silicone-acrylic-modified alkyd polymer, or a mixture thereof. The resulting waterborne coating composition includes about 2 to about 30% by weight of one or more thermal insulating fillers with the remainder being the alkyd-containing dispersion, such that the coating composition contains about 30 to about 80% by weight of the water and about 2 to about 50% by weight of the alkyd-containing polymer. The coating applied therefrom exhibits at least one of the following properties: a thermal conductivity that is less than 100 mW/mK; a weight retention of at least 70% after being heated up to 400 C as measured by thermogravimetric analysis (TGA) with a heating rate of 20 C/min.; or a weight loss of less than 50% up to a temperature of 470 C as measured by the TGA.

A dispersion of an alkyd-containing polymer dispersed in water is used to form a waterborne coating composition; the alkyd-containing polymer being an acrylic-modified alkyd polymer, a silicone-acrylic-modified alkyd polymer, or a mixture thereof. The resulting waterborne coating composition includes about 2 to about 30% by weight of one or more thermal insulating fillers with the remainder being the alkyd-containing dispersion, such that the coating composition contains about 30 to about 80% by weight of the water and about 2 to about 50% by weight of the alkyd-containing polymer. The coating applied therefrom exhibits at least one of the following properties: a thermal conductivity that is less than 100 mW/mK; a weight retention of at least 70% after being heated up to 400 C as measured by thermogravimetric analysis (TGA) with a heating rate of 20 C/min.; or a weight loss of less than 50% up to a temperature of 470 C as measured by the TGA.