A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement:SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement:SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

The invention relates to a process for producing a composite comprising: a. providing a particulate material, wherein the particulate material comprises minerals having a content of at least 30% m/m of calcium, magnesium, aluminium, silicon, potassium or iron, or a combination of two or more thereof. b. providing an aggregate, c. providing a primary additive, wherein the primary additive comprises a sugar or derivative thereof, a polyol or derivative thereof, an organic acid, an organic acid salt or an inorganic acid, or any combination of two or more thereof, d. mixing the particulate material, the aggregate and the primary additive with water to form a mixture, and e. carbonating the mixture in the presence of carbon dioxide, wherein the concentration of carbon dioxide is greater than about 2 vol %.

The invention relates to a process for producing a composite comprising: a. providing a particulate material, wherein the particulate material comprises minerals having a content of at least 30% m/m of calcium, magnesium, aluminium, silicon, potassium or iron, or a combination of two or more thereof. b. providing an aggregate, c. providing a primary additive, wherein the primary additive comprises a sugar or derivative thereof, a polyol or derivative thereof, an organic acid, an organic acid salt or an inorganic acid, or any combination of two or more thereof, d. mixing the particulate material, the aggregate and the primary additive with water to form a mixture, and e. carbonating the mixture in the presence of carbon dioxide, wherein the concentration of carbon dioxide is greater than about 2 vol %.

A method of cementing may include: mixing at least a cement dry blend, water, and a liquid activated pozzolan additive to form a cement slurry, wherein the liquid activate pozzolan additive comprises a carrier fluid and an activated pozzolan; introducing the cement slurry into a wellbore penetrating a subterranean formation; and allowing the cement slurry to set.

A method of cementing may include: mixing at least a cement dry blend, water, and a liquid activated pozzolan additive to form a cement slurry, wherein the liquid activate pozzolan additive comprises a carrier fluid and an activated pozzolan; introducing the cement slurry into a wellbore penetrating a subterranean formation; and allowing the cement slurry to set.

A method of cementing may include preparing a cement slurry by mixing at least water and a cement dry blend, wherein the cement dry blend comprises a cement and an activated pozzolan; and introducing the cement slurry into a wellbore penetrating a subterranean formation; and allowing the cement slurry to set to form a hardened mass.

A method of cementing may include preparing a cement slurry by mixing at least water and a cement dry blend, wherein the cement dry blend comprises a cement and an activated pozzolan; and introducing the cement slurry into a wellbore penetrating a subterranean formation; and allowing the cement slurry to set to form a hardened mass.

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.