Hydroxyethyl Cellulose * Concrete Admixture

1. Water retention effect

In concrete, water is essential for the hydration reaction of cement. Hydroxyethyl cellulose can form a protective film inside the concrete to slow down the evaporation rate of water. This is because there are a large number of hydroxyl groups (-OH) in its molecular structure, which can form hydrogen bonds with water molecules, thereby binding water molecules in the concrete system.

In a high-temperature dry environment, the surface water of concrete without water retaining agent will quickly dissipate, resulting in shrinkage cracks on the surface of the concrete. After adding hydroxyethyl cellulose, the concrete can retain enough water for a certain period of time, so that the cement hydration reaction continues, reducing the generation of cracks and improving the durability of the concrete.

2. Thickening effect

Hydroxyethyl cellulose can increase the consistency of concrete admixtures. It improves the rheological properties of concrete by increasing the viscosity of concrete paste. During the mixing and transportation of concrete, the appropriate consistency can prevent concrete segregation and water seepage.

3. Retarding effect

HEC has a certain delaying effect on the setting time of concrete. This is because hydroxyethyl cellulose forms an adsorption layer on the surface of cement particles, which hinders the contact between cement particles and water, thereby slowing down the hydration rate of cement.

Generally, in large-volume concrete construction, temperature cracks are easily caused due to the concentrated release of hydration heat inside the concrete. The use of hydroxyethyl cellulose can appropriately extend the setting time of concrete, make the release of hydration heat more uniform, reduce the temperature peak inside the concrete, and reduce the risk of temperature cracks.

4. Improve workability

HEC can make concrete have better workability. Workability includes fluidity, cohesion and water retention. Hydroxyethyl cellulose makes concrete easier to operate during construction through thickening and water retention.

5. Enhance crack resistance

As mentioned above, the water retention function can reduce the shrinkage cracks caused by water loss in concrete. At the same time, its thickening and workability improvement effects also help concrete form a more uniform structure during the hardening process and improve the crack resistance of concrete.

For example, in the construction of some thin-walled concrete components, the addition of hydroxyethyl cellulose can effectively prevent cracks in the components due to uneven shrinkage during the early hardening process, and improve the quality and appearance integrity of the components.