Recycled Cement Production Methods and Applications

Cementitious material and preparation method that replaces traditional cement in construction applications while reducing carbon emissions. The material comprises waste concrete powder that undergoes mechanical grinding and heat activation to produce a cement-like material with improved hydration properties. The process involves grinding concrete into smaller particles, activating them through heat treatment, and then combining the activated concrete with other cement components. This material exhibits enhanced hydration characteristics and mechanical strength compared to traditional cement, making it suitable for applications requiring improved durability and performance.

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Method for producing reclaimed cementitious fines from demolished cement-containing materials to replace virgin cement in concrete and mortar production. The method involves crushing and processing reclaimed cement-containing waste materials, including recycled concrete aggregate, demolished concrete aggregates, and demolished brick or block walls containing cement-based mortar, into finely-sized cementitious fines. These reclaimed fines can be used as a direct substitute for virgin cement in cement paste, mortar, and concrete mixes, eliminating the need for virgin cement production and associated greenhouse gas emissions.

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A method for preparing a high-performance cement additive that enables enhanced cement hydration and improved compressive strength through controlled mineralization. The additive is prepared by first crushing and sieving waste concrete into fine particles, followed by repeated crushing to achieve a particle size less than 2 mm. The crushed particles are then subjected to controlled mineralization in a reactor at 1MPa pressure with CO2 at 50% RH for 24 hours. The resulting mineralized cement additive exhibits significantly improved hydration properties and compressive strength compared to conventional cement, making it suitable for cement-based construction applications.

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A novel, carbon-negative building material comprising a 95% recycled iron-based compound with compressed carbon dioxide curing, offers enhanced durability and strength compared to conventional Portland cement. The material, known as Ferrock, incorporates compressed carbon dioxide to expedite curing and eliminates the need for added heat, while its iron-based composition reduces embodied carbon emissions. The compound's unique composition and curing process provide improved mechanical properties and reduced porosity compared to conventional Portland cement.

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A prefabricated concrete block made from a mixture of recycled aggregates and cement with reduced carbon footprint. The block combines a recycled aggregate from construction waste with a lower-carbon cement type, achieving a 17.6% reduction in CO2 emissions compared to conventional cement. The production process incorporates solar energy for electricity generation, further enhancing the eco-friendly profile of the block. The innovative composition replaces traditional volcanic stone with crushed recycled aggregates, while the cement is replaced with a lower-carbon cement type.

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A cement substitute made from waste clay and/or pottery, and a method of manufacturing the same, that reduces carbon dioxide emissions while maintaining cement's strength. The substitute is produced by mixing waste clay and purified sludge, then firing at lower temperatures (500-900°C) to create a low-temperature fired clay with enhanced hydraulic properties. The resulting low-temperature fired clay can be used as a cement substitute in cement production, achieving significant carbon dioxide reduction without compromising setting time or compressive strength.

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A cementitious material that replaces traditional Portland cement in concrete production while significantly reducing greenhouse gas emissions. The material comprises a brine slurry of water, magnesium hydroxide, and selected salts, combined with slag. When mixed with aggregate, the brine slurry forms a concrete that absorbs and retains CO2 during curing, making it a viable alternative to traditional cement. The material achieves this through its unique brine composition, which not only absorbs CO2 but also provides enhanced mechanical properties. The brine can be formulated to achieve specific CO2 absorption rates, and the material can be formulated with additives to further enhance its carbon-neutral performance.

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A method for utilizing waste fresh cement slurry as a mineral admixture in construction, particularly in concrete production. The process involves carbonizing the waste slurry through controlled CO2 injection, followed by mechanical treatment to produce a stabilized, carbon-based material that can be used as a replacement for conventional cement in concrete formulations. This approach addresses the environmental and operational challenges associated with traditional cement disposal and recycling methods.

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Alkali-activated low-carbon regenerated putty powder for building exterior wall coatings that combines waste concrete regeneration with sustainable cement production. The powder is prepared by mixing Portland cement, gray calcium, and waste concrete material with a specialized activator blend, followed by controlled hydration to form a durable, low-carbon cementitious material. The resulting powder exhibits improved mechanical properties and reduced environmental impact compared to conventional cement-based materials.

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Sintering-free solid waste-based low-carbon, low-alkali white cement that can be produced through the recycling of refractory organic and inorganic waste materials. The cement utilizes a unique combination of solid waste-derived gelling agents, zeolite-like minerals, and nano-silica sol to create a high-performance, low-alkali cement that addresses the challenges of white cement production, particularly in decorative applications. The cement achieves its strength through the synergistic effects of these waste-derived components, which provide a robust bonding system while minimizing environmental impact.

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Recycled concrete produced through the controlled crushing of waste concrete, cement, and water, resulting in a material with superior strength and durability compared to conventional concrete. The process involves crushing the waste concrete into a uniform aggregate, followed by cement and water mixing to create a composite material. This composite material is then processed through controlled crushing and separation steps to produce a high-quality recycled concrete product.

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A method for designing the optimal mix ratio of building mortar prepared from fully recycled fine aggregate, enabling complete replacement of river sand in traditional mortar production. The method employs a controlled trial approach to determine the precise mix ratio of fully recycled fine aggregate (FRA) to water, based on the specific strength of the mortar to be produced. The trial strength of the mortar is calculated using a standardized formula, with the strength of the mortar grade being specified. The method ensures optimal performance by matching the mortar's strength to the desired grade, while minimizing the impact of water absorption and setting time. This approach enables the production of mortar with improved mechanical properties, comparable to those of river sand-based mortars.

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Recyclable cement made from waste concrete that enables closing the cement cycle by using all components of waste concrete as raw material. The cement composition is optimized to overcome challenges like low reactivity of quartz and high magnesium content. The cement contains waste concrete powder along with a conditioning material like silica or limestone. The conditioning material mass is limited to 10% to avoid excessive additions. This allows full recycling of waste concrete without landfilling. The cement preparation involves crushing and grinding waste concrete, adding the conditioning material, sintering clinker, molding, and carbonization curing to produce the recyclable cement.

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A method for producing recycled cement from waste concrete through a novel approach that eliminates the need for limestone and other binding agents. The process involves a combination of waste concrete, high-purity alumina, and other supplementary materials to create a cement that can be used as a binder in concrete applications. The cement achieves superior mechanical properties compared to conventional cement while maintaining its environmental benefits.

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Environmentally friendly green recycled concrete material that combines old cement and glass aggregates with specialized additives to enhance their durability. The material comprises 100-150 parts of old cement block coarse aggregates, 60-90 parts of glass fine aggregates, 20 parts of adhesive, 30 parts of water, 20 parts of crack resistance enhancers, and 10 parts of water reducing agents.

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Sustainable concrete with improved workability and durability, comprising Portland cement, aggregates, water, additives, fibers, iron and steel slag, and white ladle furnace slag. The concrete combines recycled aggregates with these binders to achieve a dry consistency, while incorporating fibers and iron and steel slag to enhance its mechanical properties. The white ladle furnace slag contributes to the material's expansion resistance. The combination provides a reliable, workable, and durable concrete suitable for structural applications.

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A method for preparing recycled micro-powder concrete through enhanced coagulation of unhydrated cement particles from the micro-powder. The method involves using a coagulation process to rehydrate and reactivate the unhydrated cement particles, thereby improving the performance of recycled micro-powder concrete while addressing environmental concerns.

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A method for preparing fully recycled concrete through controlled aggregate gradation during the recycling process. The method involves a continuous process where crushed concrete is fed into a belt scale, which measures the particle size distribution. The belt scale continuously monitors the particle size distribution and automatically controls the mixing of recycled aggregates to maintain consistent gradation. This controlled gradation enables the production of fully recycled concrete with uniform particle sizes, eliminating the need for separate screening and silo mixing.

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A method for improving the performance of recycled concrete by enhancing its workability and compressive strength. The method involves mixing air-entraining agents, cement, water reducers, and surfactants into the recycled concrete mixture to create a more fluid and workable concrete. The surfactants, particularly polycarboxylate superplasticizer and sodium dodecylbenzene sulfonate, enhance the mixture's rheological properties, while the cement and water reducers improve its workability and compressive strength. This approach addresses the environmental and performance limitations of traditional recycled concrete by addressing its fluidity and workability issues.

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A durable, eco-friendly concrete block made from recycled industrial waste by incorporating cement admixture and ready-mixed concrete sludge. The block combines a cement-rich core with a cement- and sludge-based admixture, achieving enhanced durability through the controlled hydration reaction. The admixture composition is optimized to prevent abnormal reactions and expansion, while the cement content provides structural integrity. The resulting block exhibits superior performance characteristics, including improved compressive strength and resistance to freezing and thawing, making it suitable for applications where durability is critical.

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Algorithm for developing recycled cement using inorganic construction waste. The algorithm involves collecting and analyzing various types of inorganic construction waste, classifying them based on their chemical properties, and then deriving optimal mixing ratios for producing cement substitutes through a proprietary computational model. This enables the creation of multiple cement types from a wide range of construction waste materials, significantly expanding the scope of traditional recycled concrete technologies.

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A method for preparing recycled cement stone with lower energy consumption and carbon emissions, enabling the production of high-performance concrete materials from waste cement-based materials. The process involves crushing, sieving, and grinding the waste materials into a cement mixture, which is then shaped and cured using a controlled carbonization or carbonization-carbonization curing sequence. This approach enables the production of recycled cement stone with improved compressive strength while minimizing the environmental impact of traditional cement production processes.

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A cement-based mortar that enables the recycling of glass waste from the glassmaking industry into a cement product. The mortar combines the properties of traditional cement with the beneficial properties of glass waste, creating a sustainable solution for cement manufacturing while reducing environmental impact.

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A method for producing concrete from construction waste that replaces cement and admixtures while utilizing the natural aggregate. The process involves crushing and pulverizing construction waste to achieve particle sizes of 5mm-20mm, followed by further processing to produce a regenerated micropowder. This micropowder is then combined with the crushed waste to produce a C30 recycled aggregate concrete. The micropowder is produced through a series of crushing and pulverization steps, with the final product being a stable and consistent aggregate that can be used as a direct replacement for natural aggregate in concrete production.

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Method for producing cement with reduced environmental impact by utilizing construction waste as raw materials. The method collects and classifies construction waste into predefined groups based on chemical composition, then analyzes the composition to determine optimal mixing ratios between the waste groups. The collected waste is then processed and blended according to these ratios, with additional raw materials added to achieve the desired cement composition. This approach enables the production of cement using waste materials while minimizing the need for virgin resources and reducing waste disposal.

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Method for preparing high-performance recycled concrete with stable properties, comprising a unique combination of mechanical processing and chemical treatment of recycled aggregates. The method involves mechanical crushing to achieve optimal particle shape and size distribution, followed by a controlled chemical treatment to significantly reduce water absorption. This enables the use of higher recycled aggregate content while maintaining concrete strength and workability, eliminating the need for high-performance adhesives or expensive processing methods.

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A new type of concrete prepared from waste concrete by optimizing the composition ratio of cement, sand, and aggregate. The concrete formulation is tailored to achieve a specific ratio of water, cement, sand, and aggregate (0.51-0.59:1:1.78-1.83:3.68-3.72), with the addition of specific additives. This composition enables the creation of a concrete with improved workability, durability, and environmental sustainability compared to conventional waste concrete. The formulation balances the cement content with the aggregate ratio to achieve optimal mechanical properties while minimizing waste generation.

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A novel, environmentally friendly coagulation aggregate that replaces traditional aggregate in concrete production. The aggregate is derived from construction waste materials, specifically from masonry structures, and is processed to create a powder that can be used as a replacement for cement in concrete. The powder achieves optimal strength and workability while reducing the environmental impact of traditional aggregate production.

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A method for utilizing steel slag and waste rock in construction projects to reduce PM2.5 emissions and achieve carbon neutral cement production. The process involves blending steel slag, waste rock, and gypsum to create a cementitious material that can replace traditional cement. The blended material is then used as a coagulant in concrete production, achieving both cementitious material and coagulant properties. This integrated approach enables the production of high-performance concrete with reduced cement consumption and emissions, while also utilizing valuable waste materials.

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A novel, environmentally friendly unburned brick made from waste materials, particularly incorporating waste slag, recycled aggregate, and plant fibers. The brick combines the benefits of waste reduction, recycled materials, and enhanced durability through the incorporation of modified natural plant fibers. The brick achieves improved strength, durability, and energy efficiency through the use of plant fibers treated with nano-silica, calcium carbonate, and styrene-acrylic emulsion. The brick is produced through a vibration-compression molding process that utilizes steam curing, allowing it to be finished in 12-15 days.

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Enhanced green bricks using waste materials to achieve improved durability and performance. The innovative composition combines cement, waste slag, ash, gypsum, recycled aggregate, plant fibers, and additives to create a sustainable, low-carbon building material. The waste materials replace conventional aggregate, while the plant fibers enhance the material's strength and crack resistance. The composition achieves significant environmental benefits through reduced waste disposal and energy consumption.

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A low-cement content, renewable green concrete that utilizes reclaimed aggregate materials and waste concrete to achieve sustainable construction practices. The concrete combines natural stone, reclaimed concrete, and recycled aggregate with a reduced cement content to create a material that not only reduces environmental impact but also maintains the necessary workability and strength for construction applications.

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A process for producing baking-free aggregate products using a waste-derived aggregate, specifically cement, fly ash, gypsum, straw, cellulose ether, foaming agent, and water. The aggregate is produced through a unique combination of cement, fly ash, gypsum, and waste materials, which are mixed and extruded into ceramic bricks. The process achieves excellent thermal insulation properties while utilizing waste materials for resource conservation, reducing environmental impact. The waste-derived aggregate can be obtained from waste concrete, brick, or ceramic waste.

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