The invention provides a method for obtaining a structural element having pond ash. The method includes selecting a pond ash and adding cement to the pond ash to obtain a first mixture. Foam is sprayed to the first mixture and the said mixture is then mixed with water to form a foam concrete. The foam concrete thus obtained is then poured into a mould to obtain the desired structural element.

A mortar mix and a concrete mix incorporate a stillage admixture that improves the workability of fresh concrete and advantageously modifies the properties of the hardened concrete.

A concrete crack repair material based on nano materials includes raw materials as follows: seaweed, sulphoaluminate cement, natural sand, nano-silica fume, calcium formate, fly ash, anhydrous calcium sulphoaluminate, a polyester fiber, a water reducing agent, a corrosion inhibitor and water. By reasonably selecting the raw materials of the concrete crack repair material and making a reasonable ratio of the raw materials, the concrete crack repair material is obtained with excellent performance such as good compressive strength, bending strength and bond strength, and excellent impermeability and frost resistance. The concrete crack repair material can be used for the concrete crack repair in the marine environment, which has very important application values.

A concrete crack repair material based on nano materials includes raw materials as follows: seaweed, sulphoaluminate cement, natural sand, nano-silica fume, calcium formate, fly ash, anhydrous calcium sulphoaluminate, a polyester fiber, a water reducing agent, a corrosion inhibitor and water. By reasonably selecting the raw materials of the concrete crack repair material and making a reasonable ratio of the raw materials, the concrete crack repair material is obtained with excellent performance such as good compressive strength, bending strength and bond strength, and excellent impermeability and frost resistance. The concrete crack repair material can be used for the concrete crack repair in the marine environment, which has very important application values.

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.

Synthetic aggregates are fabricated from greater than approximately 70 wt % waste starting materials. Starting materials may be selected from granulated ground blast furnace slag, waste concrete fines, or sewage sludge ash, and mixtures thereof. The starting materials are bound together by a hydraulic cementitious binder either added to the starting materials or formed in situ. The waste starting materials, binder, and water are formed into pellets and subjected to a hydraulic reaction and carbonation in an atmosphere of greater than approximately 50% carbon dioxide at temperatures less than approximately 100 C. The resulting synthetic aggregate has a crush strength after a period of hardening equal to or greater than approximately 0.5 MPa.

Synthetic aggregates are fabricated from greater than approximately 70 wt % waste starting materials. Starting materials may be selected from granulated ground blast furnace slag, waste concrete fines, or sewage sludge ash, and mixtures thereof. The starting materials are bound together by a hydraulic cementitious binder either added to the starting materials or formed in situ. The waste starting materials, binder, and water are formed into pellets and subjected to a hydraulic reaction and carbonation in an atmosphere of greater than approximately 50% carbon dioxide at temperatures less than approximately 100 C. The resulting synthetic aggregate has a crush strength after a period of hardening equal to or greater than approximately 0.5 MPa.

Synthetic aggregates are fabricated from greater than approximately 70 wt % waste starting materials. Starting materials may be selected from granulated ground blast furnace slag, waste concrete fines, or sewage sludge ash, and mixtures thereof. The starting materials are bound together by a hydraulic cementitious binder either added to the starting materials or formed in situ. The waste starting materials, binder, and water are formed into pellets and subjected to a hydraulic reaction and carbonation in an atmosphere of greater than approximately 50% carbon dioxide at temperatures less than approximately 100 C. The resulting synthetic aggregate has a crush strength after a period of hardening equal to or greater than approximately 0.5 MPa.

Synthetic aggregates are fabricated from greater than approximately 70 wt % waste starting materials. Starting materials may be selected from granulated ground blast furnace slag, waste concrete fines, or sewage sludge ash, and mixtures thereof. The starting materials are bound together by a hydraulic cementitious binder either added to the starting materials or formed in situ. The waste starting materials, binder, and water are formed into pellets and subjected to a hydraulic reaction and carbonation in an atmosphere of greater than approximately 50% carbon dioxide at temperatures less than approximately 100 C. The resulting synthetic aggregate has a crush strength after a period of hardening equal to or greater than approximately 0.5 MPa.