Set Accelerating Admixtures Manufacturer
Set accelerating admixtures are a kind of additives to accelerate setting and early strength development of concrete. They significantly reduce the time required for concrete to transition from a plastic to a hardened state.
By accelerating the hydration reaction of cement, the set accelerating admixtures ensure that concrete loses its plasticity and hardens quickly, meeting the specific requirements of projects that demand rapid concrete formation.
Calcium formate is one of the highly effective set accelerating admixtures, serving as a lubricant and early strength enhancer for concrete. Calcium formate produced by Yuanwang is widely used in building mortar and various types of concrete.
It accelerates the hardening process of cement, reduces setting time, and prevents slow setting in low temperatures during winter construction, enabling early strength development and faster project utilization.
Chemical Mechanism of Action of Set Accelerating Admixtures
Set accelerating admixtures in concrete work by reacting with cement to speed up the hydration process of cement particles, thereby enhancing early strength and accelerating the hardening process. When using our calcium formate as a set accelerator, it promotes faster concrete setting through three key mechanisms:
Calcium hydroxide is produced during cement hydration. Calcium formate reacts with it to form calcium carbonate, which fills the pores in the concrete, creating a denser structure and accelerating the setting process.
The reaction products alter the surface environment of cement particles, speeding up the hydration of minerals like tricalcium silicate, which leads to faster formation of the cement matrix.
Calcium formate dissolves to increase the ion concentration in the liquid phase, accelerating ion migration and reactions, helping the cement paste to solidify more quickly.
Yuanwang Set Accelerating Admixture
Physical Properties
CAS Number: 544-17-2
EINECS Number: 208-863-7
Appearance: White crystals or powder
Properties: Slightly hygroscopic with a slightly bitter taste
Chemical Nature: Neutral, non-toxic, and water-soluble; forms a neutral aqueous solution
Water Solubility: Remains relatively stable across temperatures
16 g/100 g water at 0°C
18.4 g/100 g water at 100°C
Specific Gravity: 2.023 (at 20°C)
Bulk Density: 900-1000 g/L
Decomposition Temperature: >400°C
Feed-Grade vs. Construction-Grade Calcium Formate:
The primary difference between feed-grade and construction-grade calcium formate lies in their heavy metal content, with feed-grade requiring stricter purity standards.
Performance Benefits of Set Accelerating Admixture - Calcium Formate
Calcium formate reacts with calcium hydroxide to form calcium carbonate, filling pores and refining the structure. It also promotes tricalcium silicate hydration, accelerating setting and hardening, and shortening construction time.
By accelerating hydration, calcium formate increases early strength, allowing faster demolding in precast production, improving efficiency, and reducing costs.
In cold environments, calcium formate speeds up hydration, reducing free water content and improving frost resistance by filling pores with hydration products.
Calcium carbonate fills pores, creating a denser structure that resists penetration by corrosive substances like chloride or sulfate ions, increasing durability.
Calcium formate is non-toxic and environmentally safe, meeting green building standards, suitable for projects with high environmental requirements.
Works well with water reducers and air-entraining agents, enhancing early strength, durability, and concrete performance synergistically.
Accelerating Admixtures Examples
Winter Concrete ConstructionIn a bridge construction project in Heilongjiang during winter, concrete with calcium formate reached over 40% of the design strength within 3 days, ensuring the project progressed on schedule.
Precast Concrete ProductionA precast factory in Jiangsu, using calcium formate in concrete for producing piles, reduced the demolding time from 3-5 days to 1-2 days, greatly improving production efficiency and reducing costs.
Concrete Repair ProjectsIn a repair project on a major road in Beijing, repair concrete with calcium formate achieved initial set in 2 hours, reached 15 MPa compressive strength in 4 hours, and reopened traffic in 6 hours.
Shotcrete ConstructionIn a tunnel project in Sichuan, shotcrete with calcium formate increased bonding strength by 20%, effectively preventing concrete detachment.
Self-Compacting ConcreteIn a large underground basement project in Shanghai, adding calcium formate significantly boosted early strength, with the 7-day strength reaching 70% of the design strength, accelerating the subsequent construction process.
Calcium Formate Solutions for Accelerating Concrete Setting
Material SelectionCalcium formate is a set accelerating corrosion inhibiting admixture. It is chloride-free, does not corrode steel reinforcement, is environmentally friendly, and non-toxic, making it suitable for various concrete applications.
Construction Process OptimizationDissolve calcium formate in a portion of the mixing water before adding it to the concrete. This ensures full contact with the cement. Extend the mixing time by 1-2 minutes to guarantee even distribution of the calcium formate.
Environmental ControlIn winter, increase the construction temperature by heating water, using thermal tents, or insulating materials to enhance the effectiveness of calcium formate. In summer, use shading and cool aggregates to prevent overly rapid setting.
Set Accelerating & Hardening Accelerating
In concrete construction, set accelerating (speeding up setting) and hardening accelerating (speeding up hardening) are crucial.
Calcium formate is an effective additive that excels in both aspects. It reacts with calcium hydroxide produced during cement hydration, forming calcium carbonate and formic acid.
The calcium carbonate fills the pores in the concrete, making the structure denser and speeding up the setting process, achieving set accelerating.
Meanwhile, the formic acid promotes further hydration of cement minerals, such as tricalcium silicate, generating more hydration products and significantly accelerating the hardening process, achieving hardening accelerating.
This is particularly beneficial in winter construction, where low temperatures can hinder normal setting and hardening. Thanks to its unique properties, calcium formate ensures that concrete can achieve both set accelerating and hardening accelerating even in cold environments, ensuring project progress and quality.
Related Concrete Admixtures
FAQ
Have any questions? We’re here to help you out.
A set accelerator is a chemical admixture that significantly shortens the initial and final setting times of cement concrete, causing the concrete to quickly lose its plasticity and harden.
Generally, concrete with an appropriate amount of set accelerating admixtures can achieve initial setting in under 5 minutes and final setting in under 10 minutes, greatly reducing setting time compared to untreated concrete.
Cement setting can be accelerated through the following methods:
✅Select Suitable Materials: Choose cement with a high tricalcium aluminate content or appropriate fineness. Use set accelerating admixtures such as calcium chloride, sodium sulfate, or calcium formate; for shotcrete, use rapid-setting agents.
✅Optimize Construction Techniques: Extend the mixing time to ensure uniform material distribution. Strengthen the compaction process to make the concrete dense.
✅Control the Construction Environment: In cold temperatures, heat water and aggregates. In hot weather, cool the aggregates and add ice during mixing. Provide timely curing to maintain humidity.
1. Chloride – based accelerators
Example: Calcium chloride is a well – known chloride – based accelerator.
Mechanism: Chloride ions in calcium chloride can react with the tricalcium aluminate in cement. They form insoluble calcium chloroaluminate hydrates, which accelerate the formation of the cementitious structure. Additionally, chloride ions can reduce the zeta – potential of cement particles, causing them to agglomerate more quickly and thus speed up the hydration process. However, the use of calcium chloride in reinforced concrete is restricted because chloride ions can cause corrosion of steel reinforcement.
2. Sulfate – based accelerators
Example: Sodium sulfate is a typical sulfate – based accelerator.
Mechanism: Sodium sulfate reacts with the calcium hydroxide produced during cement hydration. This reaction forms calcium sulfate. The newly formed calcium sulfate then reacts with the tricalcium aluminate in cement to form ettringite more rapidly. Ettringite growth contributes to the early setting and hardening of concrete.
3. Formate – based accelerators
Example: Calcium formate.
Mechanism: Calcium formate reacts with the calcium hydroxide produced during cement hydration. The reaction products can accelerate the hydration of cement, especially in low – temperature conditions. It is relatively environmentally friendly and does not cause corrosion to steel reinforcement, making it suitable for some applications where both acceleration and corrosion protection are required.
Winter Concrete Construction:
In winter, low temperatures slow down cement hydration, extending setting and hardening times. Adding calcium formate accelerates hydration, allowing concrete to set and harden quickly in cold environments, boosting early strength and reducing the risk of freeze damage.
Precast Concrete Production:
Precast concrete requires fast demolding to improve mold turnover efficiency. Calcium formate significantly enhances early strength, allowing concrete to reach the required demolding strength in a shorter time.
Concrete Repair Projects:
For repairing damaged urban roads, using repair concrete with calcium formate allows it to set and harden within hours, quickly restoring road traffic and minimizing disruption.
Shotcrete Construction:
In tunnel and underground projects, shotcrete needs to set quickly to prevent slumping and ensure safety and quality. Calcium formate accelerates the setting of shotcrete, meeting this requirement.
Self-Compacting Concrete:
For large-scale projects like underground basements and underwater concrete pouring, adding calcium formate to self-compacting concrete ensures rapid setting and hardening after pouring, improving early strength and ensuring construction quality and schedule.
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