Techniques to Prevent Bleeding in Fresh Concrete

Concrete modifier and preparation method for improving concrete workability and durability. The modifier comprises a polymerization product derived from a combination of polyether macromonomer, acrylic acid, acrylamide, 2-acrylamid-2-methylpropanesulfonic acid, unsaturated phosphate ester, organic matter with two carbon-carbon double bonds, and deionized water. The modifier is prepared through a controlled polymerization process that incorporates an initiator, alkali, and organic matter with double bonds. The resulting modifier enhances concrete's water retention, improves slump stability, and enhances resistance to segregation and bleeding.

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Anti-bleeding agent for concrete that prevents water seepage and improves workability, particularly in sandstone applications. The agent comprises a blend of emulsifier, aluminum sulfate, sodium thiosulfate, naphthalene-based water-reducing agent, hydroxypropyl methylcellulose, and sodium lauryl sulfate. This combination provides enhanced water retention and surface tension control properties, particularly effective in reducing bleeding and improving workability. The agent's formulation allows precise control over the water-cement ratio, enabling optimal concrete production and construction conditions.

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A low-bleeding polycarboxylic acid water-reducing agent for machine-made sand that enhances concrete fluidity and cohesion. The agent is synthesized through a novel esterification process involving unsaturated polyaldehyde macromonomer, photoinitiator, and unsaturated acid. The resulting agent exhibits improved water retention properties compared to conventional agents, particularly in machine-made sand applications where conventional agents often cause bleeding and segregation.

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Anti-excretion type polycarboxylic acid water-reducing agent for concrete that prevents bleeding and segregation through controlled hydration and particle distribution. The agent combines a self-made functional water-reducing agent with nanometer coagulant, sodium hydroxide solution, white carbon black, and deionized water. The mixture is prepared through a controlled reaction process that balances hydration and coagulation to prevent excessive water release and particle separation. This agent is particularly effective in concrete with low C3A content and uneven aggregate distribution.

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Concrete composition for tunnel lining that maintains long-term fresh properties without setting delay. The composition comprises a cement additive containing a water-soluble polymer with a structural unit derived from a sulfo group-containing (meth)acrylic acid derivative and a sugar alcohol, a copolymer having a hydrolyzable group as a retention component, and a viscosity-adjusting component. The cement additive maintains water binder ratio of 45-60 mass % and medium to high fluidity while suppressing bleeding and improving cement paste cohesion.

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Polycarboxylic acid water-reducing agent for concrete that adapts to various fly ash types through molecular structure modification. The agent combines polycarboxylic acid with specific functional groups, including unsaturated carboxylic acids, esters, and phosphoric acid esters, which enhance its compatibility with fly ash. The agent's molecular structure allows it to effectively manage water reduction while maintaining cement hydration, resulting in improved workability and reduced bleeding.

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A water-reducing agent for concrete that improves workability and reduces bleeding while maintaining performance characteristics. The agent is a novel, mutually exclusive/associative polycarboxylic acid compound that combines specific monomers with a chain transfer agent. This compound offers superior compatibility with machine-made sand and gravel aggregates, enabling more efficient concrete production while maintaining optimal workability and concrete quality.

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Anti-bleeding agent for concrete and concrete admixture, which prevents concrete bleeding during transportation and construction. The agent is prepared through a polymerization reaction between a monomer and an oxidizing agent, resulting in a modified polyoxyethylene acid. The resulting polymer solution is then mixed with an oxidizing agent and a chain transfer agent to form a concrete additive. This additive can be incorporated into concrete mixtures in concentrations up to 30% of the cement content.

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Admixture for controlling bleeding of prefabricated concrete by inhibiting lagging bleeding. The admixture combines a polycarboxylic acid polymer with higher molecular weight polyether groups and amine groups to enhance cement hydration at lower temperatures. The polymer network formation and hydration product generation are optimized to prevent precipitation of free water, while maintaining sufficient cohesion and plasticity to prevent premature bleeding. This synergistic effect enables controlled bleeding behavior throughout the concrete's curing process, particularly during construction when lagging bleeding is most problematic.

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Polycarboxylic acid-based high-performance water-reducing agent for coarse aggregates with large water absorption, specifically designed for concrete with high water absorption rates. The agent combines bleeding inhibitors and adsorption inhibitors to improve concrete performance in challenging aggregate applications. It enables high-performance concrete with improved slump retention, reduced fluidity loss, and enhanced durability in marine environments. The agent's unique blend of bleeding inhibitors and adsorption inhibitors addresses common issues associated with high water absorption aggregates, such as post-bleeding, low shrinkage, and poor concrete quality.

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A nanoscale concrete admixture specifically designed for high-performance concrete applications, particularly in building construction. The admixture combines advanced air-entraining agents, defoaming agents, and retarders to address critical issues of workability and bleeding resistance in nanoscale concrete. The nanoscale cellulose fibers enhance the concrete's workability while improving its resistance to bleeding. The combination of these advanced components enables the production of high-performance concrete with improved fluidity and reduced bleeding, particularly in applications where traditional cement and sand-based mixes are facing resource constraints.

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Concrete anti-bleeding agent with enhanced water-reducing and slump-retaining properties. The agent combines a conventional polycarboxylic acid water-reducing agent with a novel, high-performance water-reducing agent. The agent achieves improved water reduction and slump retention through a synergistic combination of the two agents, enabling enhanced concrete performance in challenging construction environments.

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Concrete admixture for fair-faced concrete that enhances fluidity and strength while minimizing segregation and bleeding. The additive combines a water-reducing agent, retarder, thickener, air entraining agent, defoamer, and early strength agent in a precise ratio to achieve optimal performance characteristics. This controlled additive composition enables stable mixing, improved workability, enhanced cohesiveness, and enhanced early strength, while maintaining low sensitivity and minimal impact on concrete properties.

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Viscosity modifier for concrete that combines the high performance of polycarboxylic acid superplasticizers with the superior bleeding control properties of a specific molecular weight range. The modifier combines a high molecular weight polycarboxylic acid (600,000-200,000 g/mol) with a common molecular weight polycarboxylic acid (20,000-70,000 g/mol) in a solid content of 6-20%. This blend enhances the cement's cohesion and water retention while maintaining its high dispersion and water-reducing properties, making it particularly effective for high-strength concrete applications.

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Water-reducing agent for concrete that prevents bleeding and enhances workability. The agent combines a combination of monomers (A, B, and C) with additives (chain transfer agent, initiator, polyethylene oxide or polypropylene oxide, and paste warming rubber) to achieve effective bleeding prevention while maintaining workability.

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Concrete bleeding inhibitor for concrete transportation and pumping systems. The inhibitor is a blend of polymers and additives that prevents water from entering the concrete surface before it sets, thereby reducing bleeding and improving concrete durability. The formulation includes a combination of methacrylic acid, acrylamide, sodium persulfate, and sodium metabisulfite, along with methylenbutyl polyoxyethylene, ethyl acrylate, acrylamide, potassium persulfate, ferrous sulfate, and other additives.

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A method to prevent coagulation and bleeding in concrete by controlling the release of water-reducing agents in cold temperatures. The method involves optimizing the release profile of water-reducing agents in concrete mixtures to prevent premature coagulation and bleeding, particularly in cold conditions. The release profile is tailored to ensure that the water-reducing agent's release is matched to the concrete's hydration process, thereby preventing premature coagulation and bleeding. This approach addresses the common issue of water-reducing agents causing coagulation and bleeding in cold concrete, particularly in the initial stages of hydration.

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Method for producing concrete with reduced bleeding and improved fluidity. The method involves adding diethylene glycol (DEG) to cement and concrete mixtures in specific proportions, typically between 0.01 and 0.4 parts by mass per 100 parts by mass of cement and concrete, respectively. The DEG enhances cement hydration and reduces bleeding through its impact on the cement paste's rheology. The method also incorporates water reducing agents to further improve concrete flow characteristics. The cement used in the production process must have a high hydration rate of at least 80%. The concrete produced with this method exhibits improved workability, reduced bleeding, and enhanced durability compared to conventional concrete formulations.

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Method for manufacturing a bleeding-reducing agent in ready-mixed concrete. The method involves combining an antifoaming agent and a melamine-based fluidizing agent in a methyl cellulose-based thickener at a specific ratio to prevent bleeding in concrete. The agent composition enables uniform quality and improved durability in ready-mixed concrete, particularly in structures prone to plastic shrinkage cracking.

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