Concrete Setting Time Control Technologies

A cement-based concrete that rapidly hardens to achieve rapid repair of cracked concrete structures. The concrete composition combines Portland cement, aggregate, polymer emulsion, admixture, hydrophilic modified basalt fiber, metakaolin, calcium stearate, filler, and water. The basalt fiber is surface-modified with a hydroxyl group-containing silane compound, enhancing its bonding properties. The composition exhibits ultra-fast setting characteristics, enabling rapid hardening to repair cracks in concrete structures.

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A super slow setting concrete and a super retarder for preparing super slow setting concrete, which enables ultra-long setting times while maintaining sufficient strength. The super retarder comprises a mixture of Ca(OH)2 and Al2(SO4)3 powders, which increases the Ca2+ and SO42- ion concentration in the pore solution, thereby inhibiting early hydration reactions. The retarder is combined with a water-reducing agent that enhances the absorption of water around cementitious particles, delaying initial hydration reactions while promoting later hydration. This combination enables the concrete to achieve extended setting times while maintaining mechanical strength.

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Concrete composition that maintains workability and durability while achieving early strength, particularly in emergency construction applications. The composition comprises cement, aggregate, blast furnace slag, fly ash, and nanosilicate powder. The nanosilicate powder enhances early strength through its reaction with cement, while the sodium benzoate component prevents the undesirable side reactions associated with carbonyl diamide. This combination ensures improved workability and durability while maintaining the desired early strength.

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Concrete composition for structural repair and reinforcement that enhances durability and resistance to environmental degradation. The composition comprises cement, aggregate, blast furnace slag, silica fume, calcium sulfuraluminate, and nanosilicate powder. The composition is formulated with a specific ratio of these components, particularly the blast furnace slag and silica fume, to achieve enhanced salt and sulfuric acid resistance while maintaining early strength. The composition includes a novel admixture that combines butylene glycol with the blast furnace slag and silica fume to enhance water retention and prevent cracking. The composition is particularly effective for repairing concrete structures that are prone to salt and sulfuric acid attack.

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Concrete construction method that enables simultaneous finishing of concrete floors in adjacent work zones. The method involves blending an initial mixing amount of an admixture into the concrete for the first period, followed by a second blending of a larger admixture in the second period. The expanded concrete and accelerated hardening admixture are mixed in a constant ratio before being applied to the concrete. This approach enables finishing work to be performed at the same time as concrete placement, significantly reducing the overall construction time.

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A special admixture for ultra-slow concrete that enhances its setting time while maintaining strength. The admixture combines modified phosphogypsum, sodium gluconate, sodium tripolyphosphate, sulfamic acid, hydroxypropyl methylcellulose, and sodium polyacrylate in specific weight ratios. This formulation delays cement hydration, particularly in high-temperature applications, while maintaining early strength and durability. The combination of these components effectively reduces cement hydration rates, enabling longer pouring times without compromising concrete performance.

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Additive mixture for concrete that delays setting time by up to 2-4 hours. The mixture comprises sodium gluconate, molasses, water, naphthalene sulfonic acid, and formalin. The gluconate and molasses slow down hydration, while naphthalene sulfonic acid enhances wetting and emulsification. Formalin contributes to a more stable setting process. This additive can be incorporated into ready-mix concrete to achieve controlled setting times for construction applications.

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Cement composition and method for producing the cement composition that enables rapid self-sustainability of concrete after mixing, while maintaining excellent workability. The composition comprises a base cement and an admixture containing a calcium silicate-based hardening accelerator and ultra-rapid-hardening cement, with specific mass ratios and content limits. The admixture enhances the cement's self-healing properties through controlled calcium silicate activation, while the ultra-rapid-hardening cement accelerates the hardening process. The composition demonstrates rapid self-sustainability and improved workability compared to conventional cement mixtures.

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A fast-setting concrete repair material that combines calcium aluminate with anhydrite for enhanced rapid hardening. The composition comprises a cement matrix, a calcium aluminate admixture, fine aggregate, anhydrite, sodium carbonate, and tartaric acid. The calcium aluminate admixture has a vitrification rate of 80% or more and a specific ratio of calcium to alumina (1.5:1 to 2.0:1). The admixture also contains sodium carbonate and tartaric acid. The cement content is between 100 parts by mass and 1900 parts by mass with respect to the admixture. The admixture is formulated to maintain consistent setting time across a range of environmental temperatures, with a maximum of ±20% change in initial setting time. The material incorporates short fibers and a salt adsorbent to enhance durability.

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Concrete early strength agent for enhancing both early and later strength of concrete. The agent comprises a combination of calcium chloride, calcium nitrite, calcium nitrate, triethanolamine, hydroxymethyl cellulose, polycarboxylic acid water reducing agent, nano silica, diatomaceous earth, and methacrylic acid. The agent provides rapid hydration of cement and concrete components, while its formulation ensures consistent performance across various concrete mix compositions.

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Pozzolanic cementitious composition comprising an activated clay between 20-85%, a limestone between 10-75%, and a setting regulator between 3-15%. The composition is formulated to achieve superior performance characteristics such as mechanical strength, Blaine, density, durability, workability, and chloride ion resistance compared to conventional cement formulations. The composition is designed to meet specific requirements for various cement applications, including general use, high early strength, and sulfate-resistant cements.

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Two-material ready-mixed concrete shipping type hard concrete material and a ready-mixed concrete shipping type hard concrete composition. The composition includes hardened cement and a curing accelerator containing aluminum, sulfur, sodium, and fluorine in a controlled ratio, where the natroalnite content in the curing accelerator is within a specific range.

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Ready-mixed concrete shipping type hard concrete material and composition for enhanced early strength development and long-term durability. The material combines cement, hardeners, and a specialized cement additive that incorporates an aluminum sulfate-based curing accelerator. This additive, which includes a sleeping agent that prevents premature hydration, enables controlled hardening and improved strength development during transportation. The composition achieves optimal performance by balancing early strength development with sufficient pot life, making it suitable for applications requiring rapid construction and long-term durability.

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High-performance concrete with enhanced early strength through a novel combination of additives and reinforcement. The concrete combines a proprietary quick-setting agent with a specialized reinforcement system comprising graphene oxide and nano-hydroxyapatite. The agent, which penetrates the cement hydration layer, accelerates calcium silicate hydration and forms calcium silicate hydrate gel. The reinforcement system, comprising graphene oxide and nano-hydroxyapatite, enables rapid coagulation of cement particles and forms a network structure that significantly enhances early strength. The combination provides superior early strength and resistance to cracking compared to conventional fast-setting concrete formulations.

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Ultra-early strength concrete with improved bonding properties for pavement repair applications. The concrete formulation combines a unique blend of cement, sandstone, and quick-setting particles with additives like polyethylene glycol and water-reducing agents. This composition enables enhanced bonding between the old and new surfaces while maintaining superior early strength and durability compared to conventional cement-based repairs. The formulation addresses the specific challenges associated with pavement maintenance by addressing early strength, bonding, and durability requirements for rapid traffic operations.

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Portland cement with improved properties through the incorporation of a novel mineral additive. The additive, comprising a specific type of kaolinite mineral, enhances the cement's hydraulic activity while reducing its water demand. The additive also contributes to increased compressive strength in the early stages of hardening. The cement composition includes a clinker, dihydrate, diatomaceous earth, fireclay, kaolin, limestone, chemical additive, and superplasticizer. The additive's specific composition and dosage are optimized to achieve these enhanced properties while maintaining the cement's chemical and mineralogical integrity.

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A hardening agent for concrete that enables rapid hardening concrete delivery from a ready-mixed concrete plant. The agent, which is a dormant fast-hardening material, is added to the concrete during transportation. When mixed with cement and water, it triggers the hydration and hardening of the concrete, achieving faster hardening times than conventional cement-based systems. The agent can be formulated to achieve optimal performance in both short-term and long-term hardening conditions, with the agent enabling 120-minute or more hardening times.

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A rapid concrete composition for road repair and reinforcement that achieves improved durability and reduced cracking through a novel combination of cement and latex. The composition comprises a high Belite calcium sulfoaluminate cement, a high Belite calcium-sulfur aluminate cement, and a styrene-butadiene-styrene (SBS) latex. The SBS latex is added to the cement to enhance its mechanical properties while reducing shrinkage and cracking. The latex film also improves adhesion between the cement and aggregate. The composition is prepared with a specific ratio of cement to latex, with a water content optimized for rapid curing. The resulting concrete exhibits improved durability and reduced cracking compared to conventional cement-based repairs.

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Accelerating shotcrete production by enhancing its setting properties through the use of a novel accelerator. The accelerator, comprising β-naphthalenesulfonate formaldehyde condensate, is added to the shotcrete formulation to rapidly improve its setting characteristics. This enables faster shotcrete application and reduced application time, while maintaining the shotcrete's workability, durability, and cement content.

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A liquid phase concrete accelerator that maintains its dissolved state even at low temperatures, enabling early strength development in concrete construction. The composition comprises sodium sulfate, sodium nitrate, aluminum sulfate, sodium thiocyanate, and a sterically hindered alkanolamine, which are combined in a specific ratio to achieve optimal performance. This liquid accelerator can be used in conventional concrete mixing processes, eliminating the need for separate storage and mixing of powder accelerators. The composition can be applied to existing concrete formulations and construction methods, including the conventional cold weather curing process.

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