An embodiment includes a Class C fly ash (CFA) cementitious composition with a controllable setting time comprising at least one Class C fly ash; at least one alkali hydroxide; at least one source of phosphate; and water. Alternate embodiments include a Class C fly ash (CFA) cementitious composition with a solid activator comprising at least one Class C fly ash; at least one alkali carbonate; at least one source of phosphate; and water.

An embodiment includes a Class C fly ash (CFA) cementitious composition with a controllable setting time comprising at least one Class C fly ash; at least one alkali hydroxide; at least one source of phosphate; and water. Alternate embodiments include a Class C fly ash (CFA) cementitious composition with a solid activator comprising at least one Class C fly ash; at least one alkali carbonate; at least one source of phosphate; and water.

A nanozeolite modified green concrete contains alkali-activated natural pozzolan. Natural pozzolan is a green and sustainable material, potentially useful in green concrete, e.g., to curb greenhouse gas emissions associated with ordinary Portland cement production. Nanozeolite (NZ) is present as an additive to the green concrete, e.g., at 3 to 5 wt. %, of natural pozzolan to improve strength development and microstructural properties, resulting in superior strength and denser microstructure compared to a green concrete without nanozeolite.

A nanozeolite modified green concrete contains alkali-activated natural pozzolan. Natural pozzolan is a green and sustainable material, potentially useful in green concrete, e.g., to curb greenhouse gas emissions associated with ordinary Portland cement production. Nanozeolite (NZ) is present as an additive to the green concrete, e.g., at 3 to 5 wt. %, of natural pozzolan to improve strength development and microstructural properties, resulting in superior strength and denser microstructure compared to a green concrete without nanozeolite.

Systems and methods are provided for making aggregate from comingled waste plastics. For example, there is provided a method of making a preconditioned absorptive resin aggregate, the method including: obtaining a supply of granulated mixed plastic waste treated with a preconditioning agent that comprises at least one of calcium oxide and calcium hydroxide; mixing the supply of granulated mixed plastic waste treated with the calcium oxide preconditioning agent with one or more additives to form a plastic waste mixture, the one or more additives comprising pozzolans; hot extruding the plastic waste mixture to form an extruded product comprising waste plastic material; cooling the extruded product; and processing the extruded product to form an aggregate. Products incorporating such aggregates, such as, for example, lightweight construction blocks, are also provided. Also provided are methods of forming a waste plastics feedstock.

Systems and methods are provided for making aggregate from comingled waste plastics. For example, there is provided a method of making a preconditioned absorptive resin aggregate, the method including: obtaining a supply of granulated mixed plastic waste treated with a preconditioning agent that comprises at least one of calcium oxide and calcium hydroxide; mixing the supply of granulated mixed plastic waste treated with the calcium oxide preconditioning agent with one or more additives to form a plastic waste mixture, the one or more additives comprising pozzolans; hot extruding the plastic waste mixture to form an extruded product comprising waste plastic material; cooling the extruded product; and processing the extruded product to form an aggregate. Products incorporating such aggregates, such as, for example, lightweight construction blocks, are also provided. Also provided are methods of forming a waste plastics feedstock.

A method of manufacturing an activated pozzolan composition includes: (i) grinding a natural pozzolan, alone or with another mineral component that is not cement clinker, to form a finely ground pozzolan component having a first d90 in a range of about 10 m to about 45 m and a first d10 less than about 5 m; and (ii) blending, without intergrinding, the finely ground pozzolan component with a coarse particulate mineral component comprised of coarse mineral particles not interground with the fine interground particulate component, the coarse particulate component having a second d90 greater than the first d90 and a second d10 greater than the first d10. The natural pozzolan can be one or more of natural pozzolanic deposits, volcanic ash, metakaolin, shale dust, calcined clay, trass, and pumice.

A method of manufacturing an activated pozzolan composition includes: (i) grinding a natural pozzolan, alone or with another mineral component that is not cement clinker, to form a finely ground pozzolan component having a first d90 in a range of about 10 m to about 45 m and a first d10 less than about 5 m; and (ii) blending, without intergrinding, the finely ground pozzolan component with a coarse particulate mineral component comprised of coarse mineral particles not interground with the fine interground particulate component, the coarse particulate component having a second d90 greater than the first d90 and a second d10 greater than the first d10. The natural pozzolan can be one or more of natural pozzolanic deposits, volcanic ash, metakaolin, shale dust, calcined clay, trass, and pumice.

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.

Some embodiments of the present invention comprise a method of cementing comprising: placing a settable composition into a well bore, the settable composition comprising remediated coal ash, hydraulic cement, and water; and allowing the settable composition to set. Other embodiments comprise a method of cementing comprising: placing a settable composition into a well bore, the settable composition comprising remediated coal ash, calcium hydroxide (lime), and water; and allowing the settable composition to set. Other embodiments comprise a settable composition comprising: remediated coal ash, hydraulic cement, calcium hydroxide, natural pozzolan and water; and allowing the composition to set. Other embodiments comprise a settable composition comprising remediated coal ash and any combination of hydraulic cement, calcium hydroxide, slag, fly ash, and natural or other pozzolan.