Concrete admixtures are essential components in modern concrete construction. These chemical compounds are carefully designed and manufactured to enhance the performance and quality of concrete. Admixtures are added to the concrete mix in precise quantities, either during batching or on-site, to achieve specific desired effects.
Here are 20 types of admixtures commonly used in concrete
1.Water Reducing Admixtures:
Water Reducing Admixtures (WRAs), sometimes referred to as plasticizers, are designed to free trapped water that is present in concrete mixtures and are used in a variety of applications to ensure or improve workability. When cement clinker is ground, electrical charges are created on the surface of the particles.
2.Plasticizers
a plasticizer is a low-volatility liquid or solid substance that’s added to a raw polymer like a type of plastic or rubber to improve its flexibility, make it easier to shape and mold, and reduce friction on its surface.
3.Superplasticizers (SPs)
also known as high range water reducers, are additives used for making high-strength concrete or to place self-compacting concrete. Superplasticizers have a stronger water-reducing effect than plasticizers and can greatly increase the flowability and workability of concrete.
In concrete, Polycarboxylate Superplasticizer (Powder) is the most common high-efficiency water reducer, it has unparalleled competitiveness,reference《Polycarboxylate Superplasticizer (Powder) guide》
4.Accelerators
A cement accelerator is an admixture for the use in concrete, mortar, rendering or screeds. The addition of an accelerator speeds the setting time and thus cure time starts earlier speed up the setting and hardening process of concrete, reducing the time required for curing.5. Retarders: Retarders slow down the setting time of concrete, allowing for longer placement and workability.
5.Retarders
Cement Retarders A chemical agent used to increase the thickening time of cement slurries to enable proper placement. The need for cement retardation increases with depth due to the greater time required to complete the cementing operation and the effect of increased temperature on the cement-setting process.
6.Air Entraining Admixtures
Corrosion Inhibitors: Corrosion inhibitors protect the reinforcement steel in concrete from corrosion, extending the lifespan of structures.
7.Pozzolanic Admixtures
Pozzolanic or Mineral admixtures refer to the finely divided materials which are added to obtain specific engineering properties of cement mortar/concrete.Pozzolanic admixtures, such as fly ash and silica fume, enhance the strength, durability, and workability of concrete.
8.Pozzolanic Admixtures
Pozzolanic or Mineral admixtures refer to the finely divided materials which are added to obtain specific engineering properties of cement mortar/concrete.Pozzolanic admixtures, such as fly ash and silica fume, enhance the strength, durability, and workability of concrete.
9.Set Controlling Admixtures
Set-controlling admixtures are used to modify the time of setting (ACI 212.3R). Retarding admixtures extend the time of setting. They are used in hot weather to compensate for the effects of high temperature. Accelerating admixtures reduce the time of setting and accelerate early strength development.These admixtures control the setting time of concrete, ensuring proper placement and finishing.
10.Shrinkage Reducing Admixtures
Shrinkage reducing concrete mixture is typically comprised of polyoxyalkylene alkyl ether or similar composition. When such admixture is added to concrete during the batching stage, it can significantly reduce both the early and long-term drying shrinkage; reductions of 30 to 50% can be achieved. admixtures minimize drying shrinkage, preventing cracking and improving long-term durability.
11.Alkali-Silica Reaction Inhibitors
An Alkali-silica reactivity-inhibiting admixture offers proven chemistry for mitigating ASR in concrete. This ready-to-use liquid admixture is formulated for use in high-alkali concrete to improve the durability of concrete and extend service life.These admixtures prevent the alkali-silica reaction which can cause concrete expansion, cracking, and failure.
12.Coloring Admixtures
Coloring admixtures are used to add pigments or dyes to concrete, creating decorative finishes and aesthetic appeal.
13.Waterproofing Admixtures
Waterproofing admixtures reduce the permeability of concrete, preventing water penetration and improving moisture resistance.
As one of the important admixtures of concrete, the use of Concrete Waterproofing Admixture has strict requirements. For detailed operation, please read the article 《Concrete Waterproofing Admixture》
14.Viscosity Modifying Admixtures
These admixtures improve the viscosity and stability of concrete, making it suitable for self-leveling and high-flow applications.
15.Fiber Reinforcing Admixtures
Fiber reinforcing admixtures add synthetic or natural fibers to concrete, enhancing its strength and toughness.
16.Bonding Admixtures
Bonding admixtures improve the bond between new and existing concrete surfaces, increasing the overall strength and durability of the structure.
17.Sound-Reducing Admixtures
Sound reducing admixtures reduce noise transmission through concrete, making it ideal for soundproofing applications.
18.Pumping Aid Admixtures
These admixtures enhance the permeability of concrete, allowing for easy transportation and placement at greater distances.
19.Curing Admixtures
Curing admixtures help in the proper curing of concrete, ensuring optimal strength development and reducing the risk of cracking.
20.Self-Healing Admixtures
Self-healing admixtures contain special materials that can repair micro-cracks in concrete, enhancing durability and extending the lifespan of structures.
These are just some of the many admixtures available for use in concrete construction. The choice of an admixture depends on the specific requirements of the project, desired properties of the concrete, and environmental conditions.
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