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.

An improved process for the preparation of aggregates for use with mixtures of various carbonatable substances, in particular mixtures comprising pulverised fuel ash and/or steel slag. The mixtures also comprise a carbonatable binder. The process comprises the steps of a. blending a combination of two carbonatable wastes, b. mixing the blended carbonatable waste with a carbonatable binder, c. mixing the blended carbonatable waste and binder with water, and d. carbonating the damp blended carbonatable waste in the presence of carbon dioxide.

An improved process for the preparation of aggregates for use with mixtures of various carbonatable substances, in particular mixtures comprising pulverised fuel ash and/or steel slag. The mixtures also comprise a carbonatable binder. The process comprises the steps of a. blending a combination of two carbonatable wastes, b. mixing the blended carbonatable waste with a carbonatable binder, c. mixing the blended carbonatable waste and binder with water, and d. carbonating the damp blended carbonatable waste in the presence of carbon dioxide.

Provided herein are methods and compositions utilizing one or more cementitious replacement materials, one or more alkaline activating materials, and, optionally one or more bonding materials and/or one or more setting time enhancer materials. The one or more cement precursors comprises one or more of calcareous sludge; paper pulp, biomass flyash; bag house dust; biomass sludge; filter cakes from bio industry's and wastewater treatment; bio ash; biomedical ash; agricultural ash; sugar cane bagasse; rice husk ash; palm oil fuel ash; oxygen furnace slags; plant stalks; bio char; starch; pyrophyllite; or a combination thereof. The one or more alkaline activating agents comprises potassium silicate, potassium hydroxide, sodium hydroxide, sodium silicate, calcium hydroxide, magnesium hydroxide, reactive magnesium oxide, calcium chloride, sodium carbonate, silicone dioxide, sodium aluminate, calcium sulfate, sodium sulfate, or dolomite, or a combination thereof. The system comprises a vertical impact mixer.

Provided herein are methods and compositions utilizing one or more cementitious replacement materials, one or more alkaline activating materials, and, optionally one or more bonding materials and/or one or more setting time enhancer materials. The one or more cement precursors comprises one or more of calcareous sludge; paper pulp, biomass flyash; bag house dust; biomass sludge; filter cakes from bio industry's and wastewater treatment; bio ash; biomedical ash; agricultural ash; sugar cane bagasse; rice husk ash; palm oil fuel ash; oxygen furnace slags; plant stalks; bio char; starch; pyrophyllite; or a combination thereof. The one or more alkaline activating agents comprises potassium silicate, potassium hydroxide, sodium hydroxide, sodium silicate, calcium hydroxide, magnesium hydroxide, reactive magnesium oxide, calcium chloride, sodium carbonate, silicone dioxide, sodium aluminate, calcium sulfate, sodium sulfate, or dolomite, or a combination thereof. The system comprises a vertical impact mixer.

An improved process for the preparation of aggregates for use with mixtures of various carbonatable substances, in particular mixtures comprising pulverised fuel ash and/or steel slag. The mixtures also comprise a carbonatable binder. The process comprises the steps of a. blending a combination of two carbonatable wastes, b. mixing the blended carbonatable waste with a carbonatable binder, c. mixing the blended carbonatable waste and binder with water, and d. carbonating the damp blended carbonatable waste in the presence of carbon dioxide.

An improved process for the preparation of aggregates for use with mixtures of various carbonatable substances, in particular mixtures comprising pulverised fuel ash and/or steel slag. The mixtures also comprise a carbonatable binder. The process comprises the steps of a. blending a combination of two carbonatable wastes, b. mixing the blended carbonatable waste with a carbonatable binder, c. mixing the blended carbonatable waste and binder with water, and d. carbonating the damp blended carbonatable waste in the presence of carbon dioxide.

A controlled low strength material has constituents that include a cement, an aggregate, and a water. The aggregate includes concrete demolition waste. The controlled low strength material has a compressive strength that does not exceed 8.3 MPa, measured at 28 days. The controlled low strength material can alternately include a heavy oil fuel ash and the controlled low strength material can have a compressive strength that does not exceed 2.10 MPa, measured at 28 days.

A controlled low strength material has constituents that include a cement, an aggregate, and a water. The aggregate includes concrete demolition waste. The controlled low strength material has a compressive strength that does not exceed 8.3 MPa, measured at 28 days. The controlled low strength material can alternately include a heavy oil fuel ash and the controlled low strength material can have a compressive strength that does not exceed 2.10 MPa, measured at 28 days.

Compositions and methods of forming compositions for a controlled low strength material (CLSM) comprising heavy oil fuel ash (HOFA) and recycled concrete powder (RCP) waste with natural and recycled aggregates and water are provided. In some embodiments, small quantities of Portland cement are also utilized. The recycled concrete powder contains primarily calcite and quartz. The CLSM can be used as a flowable compacted fill in structural and non-structural construction applications.