Concrete accelerators mainly function through the following ways:
- Promote cement hydration: Certain components in accelerators can accelerate the hydration reaction of cement clinker minerals, generating more hydration products to improve the early strength of concrete.
- Form double salts: Some components in accelerators can react with cement hydration products to form insoluble double salts, increasing concrete density and enhancing early strength.
- Reduce hydration heat: Specific accelerators can lower the hydration heat of cement, reduce temperature stress, prevent concrete cracking, and indirectly improve early strength.
- Significantly improve early strength: After adding accelerators, the 1-day and 3-day strength of concrete can increase by over 50%, and the 7-day strength by over 20%, greatly shortening the curing period and accelerating construction progress.
- Improve concrete performance: Accelerators can enhance concrete's density, impermeability, frost resistance and other properties, extending its service life.
- Strong adaptability: Accelerators are suitable for various types of concrete, such as ordinary concrete, high-strength concrete and pumped concrete.
- Easy to use: Accelerators are generally in powder or liquid form, which can be directly added to concrete mixers for convenient application.
According to different chemical compositions, accelerators can be divided into the following categories:
- Inorganic salt accelerators: Such as calcium chloride, sodium sulfate and calcium sulfate. They are low-cost but have certain corrosiveness.
- Organic compound accelerators: Such as triethanolamine and calcium formate. They have significant early-strength effects but are relatively expensive.
- Composite accelerators: Composed of multiple early-strength components, they have advantages of good early-strength effect and few side effects, making them the most widely used type currently.
- Select appropriate type and dosage: Choose the right accelerator type and dosage based on actual engineering conditions to achieve the optimal early-strength effect.
- Strictly control concrete mix ratio and construction process: The addition of accelerators will affect concrete's setting time and fluidity, so strict control of mix ratio and construction process is necessary.
- Pay attention to curing: Concrete with accelerators still requires proper curing to ensure the development of later strength.
As an efficient and practical concrete admixture, concrete accelerators play an important role in improving early strength, shortening curing periods and enhancing construction efficiency. With the continuous development of science and technology, the types and performance of accelerators will be further improved, making greater contributions to the development of modern construction projects.
