It has been unexpectedly discovered that the addition of ground-granulated blast-furnace slag to non-spec fly ash significantly improves the properties of the non-spec fly ash to the extent it can be certified under ASTM C618 and AASHTO 295, as either a Class F or Class C fly ash. Other pozzolans may also be used for this beneficiation process. Many pozzolans are experimentally tested and may be used to beneficiate non-spec fly ash into certifiable Class F fly ash. Additionally, this disclosure provides a method of converting a Class C fly ash to a more valuable Class F fly ash. This discovery will extend diminishing Class F fly ash supplies and turn non-spec fly ash waste streams into valuable, certified fly ash pozzolan which will protect and enhance concrete, mortars and grouts.

It has been unexpectedly discovered that the addition of ground-granulated blast-furnace slag to non-spec fly ash significantly improves the properties of the non-spec fly ash to the extent it can be certified under ASTM C618 and AASHTO 295, as either a Class F or Class C fly ash. Other pozzolans may also be used for this beneficiation process. Many pozzolans are experimentally tested and may be used to beneficiate non-spec fly ash into certifiable Class F fly ash. Additionally, this disclosure provides a method of converting a Class C fly ash to a more valuable Class F fly ash. This discovery will extend diminishing Class F fly ash supplies and turn non-spec fly ash waste streams into valuable, certified fly ash pozzolan which will protect and enhance concrete, mortars and grouts.

The invention provides methods and compositions for carbonation of a wet cement mix. The wet cement mix may be carbonated prior to addition of aggregates, admixture, SCM, and/or other components to produce a carbonated concrete mix. The methods and compositions may include high shear mixing of a cement or concrete mix, either during or before carbonation.

The invention provides methods and compositions for carbonation of a wet cement mix. The wet cement mix may be carbonated prior to addition of aggregates, admixture, SCM, and/or other components to produce a carbonated concrete mix. The methods and compositions may include high shear mixing of a cement or concrete mix, either during or before carbonation.

High-strength concrete-like FG blends and methods for producing them are described. The blend includes FG, hydraulic cement, additional alkali material, and pozzolanic material. The blend further includes an admixture used in the formulation of concrete. The blend further includes an aggregate. The aggregate is a coarse aggregate or a fine aggregate.

The invention relates to the use of calcium nitrate to reduce the pore size distribution of a hardened cementitious composition, preferably, a hardened concrete composition, wherein the cementitious (concrete) composition comprises between 1 weight % to 4 weight % of calcium nitrate of the cement content of the cementitious composition, depending on the type of cement. This results in a reduced permeability for the set cementitious (concrete) composition for carbon dioxide (CO.sub.2) and thus an elevated resistance towards carbonation. The invention furthermore relates to a method for producing such a hardened cementitious (concrete) composition and a pourable and curable (wet) concrete composition. The invention also relates to a steel reinforced concrete solid having an elevated resistance towards carbonation and a method for producing a steel reinforced concrete solid having an elevated resistance towards carbonation.

The invention relates to the use of calcium nitrate to reduce the pore size distribution of a hardened cementitious composition, preferably, a hardened concrete composition, wherein the cementitious (concrete) composition comprises between 1 weight % to 4 weight % of calcium nitrate of the cement content of the cementitious composition, depending on the type of cement. This results in a reduced permeability for the set cementitious (concrete) composition for carbon dioxide (CO.sub.2) and thus an elevated resistance towards carbonation. The invention furthermore relates to a method for producing such a hardened cementitious (concrete) composition and a pourable and curable (wet) concrete composition. The invention also relates to a steel reinforced concrete solid having an elevated resistance towards carbonation and a method for producing a steel reinforced concrete solid having an elevated resistance towards carbonation.

Provided are cementitious mixtures and processes for reinforcing a cementitious matrix. In one form of the process for reinforcing a cementitious matrix includes the steps of mixing a mineral cement and one or more populations of synthetic copolymer microfibers including about 1 mol. % to about 25 mol. % and from about 75 mol. % to about 99.5 mol. % of propylene monomeric units.

Disclosed are hydrophobic finish compositions and cementitious articles made with the hydrophobic finish compositions. In some embodiments, the article is a waterproof gypsum panel surface reinforced with inorganic mineral fibers that face a flexible and hydrophobic cementitious finish possessing beneficial waterproofing properties. The waterproof gypsum panels of the invention have many uses, such as, tilebacker board in wet or dry areas of buildings, exterior weather barrier panel for use as exterior sheathing, and roof cover board having water durability and low surface absorption. The flexible and hydrophobic cementitious finish can include fly ash, film-forming polymer, silane compound (e.g., alkyl alkoxysilane), an extended flow time retention agent including either one or more carboxylic acids, salts of carboxylic acids, or mixtures thereof, and other optional additives.

Disclosed are hydrophobic finish compositions and cementitious articles made with the hydrophobic finish compositions. In some embodiments, the article is a waterproof gypsum panel surface reinforced with inorganic mineral fibers that face a flexible and hydrophobic cementitious finish possessing beneficial waterproofing properties. The waterproof gypsum panels of the invention have many uses, such as, tilebacker board in wet or dry areas of buildings, exterior weather barrier panel for use as exterior sheathing, and roof cover board having water durability and low surface absorption. The flexible and hydrophobic cementitious finish can include fly ash, film-forming polymer, silane compound (e.g., alkyl alkoxysilane), an extended flow time retention agent including either one or more carboxylic acids, salts of carboxylic acids, or mixtures thereof, and other optional additives.