A vegetal concrete masonry unit is provided which comprises cooked crop residues, binder and pulverized fuel ash in a mass ratio of 1:1:1.5 to 1:1.5:3.

Class C fly ash-based cementitious materials, concretes, and related techniques are disclosed. In accordance with some embodiments, an activated class C fly ash-based cementitious material may be produced by intergrinding class C fly ash (e.g., classified to remove quartz and/or other contaminants and, thus, increase the reactive materials present), an activator, sodium citrate, borax, and a polycarboxylate material. The class C fly ash may have an amorphous glass content of about 60 wt % or more, a calcium oxide (CaO.sub.2) content of about 20 wt % or more, and a quartz content of about 10 wt % or less. The activator may be a chemical which reacts with class C fly ash to form strätlingite structures therein when introduced with water. In some cases, the cementitious material may be provided as an all-in-one powder blend. In some case, techniques disclosed herein may be utilized in providing a fast-setting flowable fill material.

A method of reducing sulfur concentration in fly ash, flue gas desulfurization (FGD) ash, and mixtures thereof by contacting the fly ash, FGD ash, or mixtures thereof with an aqueous acidic solution, for a time, at a temperature, and at a liquid-to-solid ratio wherein the sulfur concentration within the fly ash, FGD ash, or mixture thereof is reduced to no more than 5 wt % SO.sub.3 based on the total weight of dry fly ash, FGD ash, or mixture thereof so treated.

A nano-modified dry-mixed alkali-activated cementitious, or one-part geopolymer cement (OPgC), material with high early strength is provided for rapid repair of cement-based infrastructure components. The OPgC may include an aluminosilicate rich material, an alkali material and a nano-modifier, and optionally include other functional admixtures and fibers. The OPgC can be freshly mixed with water to obtain a repairing material. The OPgC may mix with water and fine or coarse aggregate to form mortar or concrete. The OPgC can be an alternative binding matrix for the development of an environmentally friendly and cost effective rapid repair material.

A nano-modified dry-mixed alkali-activated cementitious, or one-part geopolymer cement (OPgC), material with high early strength is provided for rapid repair of cement-based infrastructure components. The OPgC may include an aluminosilicate rich material, an alkali material and a nano-modifier, and optionally include other functional admixtures and fibers. The OPgC can be freshly mixed with water to obtain a repairing material. The OPgC may mix with water and fine or coarse aggregate to form mortar or concrete. The OPgC can be an alternative binding matrix for the development of an environmentally friendly and cost effective rapid repair material.

A method for disposing of fly ash. After the fly ash has been processed using the method contained herein, this fly ash can be disposed of more easily because of the reduced toxicity of the final product. Also, this converted fly ash may be recycled and used as a material or aggregate in concrete. The method includes the treatment of dioxins found in fly ash found in waste incinerator flue from waste incineration power plants which includes collecting the fly ash, putting the fly ash into a hermetic device and treating the fly ash through various heating steps and thereafter lowering an environmental temperature in the hermetic heating device, which results in a significant reduction of dioxins in the fly ash.

A method for disposing of fly ash. After the fly ash has been processed using the method contained herein, this fly ash can be disposed of more easily because of the reduced toxicity of the final product. Also, this converted fly ash may be recycled and used as a material or aggregate in concrete. The method includes the treatment of dioxins found in fly ash found in waste incinerator flue from waste incineration power plants which includes collecting the fly ash, putting the fly ash into a hermetic device and treating the fly ash through various heating steps and thereafter lowering an environmental temperature in the hermetic heating device, which results in a significant reduction of dioxins in the fly ash.

A method of making fly ash comprising combusting a fuel in the presence of a mineral additive, wherein the mineral additive comprises at least one silicate, fly ash obtained by said method and the use of said fly ash as a pozzolan, for example for use in a cementitious composition such as cement and concrete.

A method of making fly ash comprising combusting a fuel in the presence of a mineral additive, wherein the mineral additive comprises at least one silicate, fly ash obtained by said method and the use of said fly ash as a pozzolan, for example for use in a cementitious composition such as cement and concrete.

An embodiment comprises a method of treating a subterranean formation comprising: providing a treatment fluid comprising a kiln dust, biowaste ash, and water; and introducing the treatment fluid into a subterranean formation. Another embodiment comprises a method of cementing comprising: introducing a cement composition into a subterranean formation, wherein the cement composition comprises a kiln dust, biowaste ash, and water; and allowing the cement composition to set in the subterranean formation. Yet another embodiment comprises a method comprising: providing a spacer fluid comprising biowaste ash and water; introducing the spacer fluid into a well bore to displace at least a portion of a first fluid from the well bore; and introducing a cement composition into the well bore, wherein the spacer fluid separates the cement composition and the first fluid.