What Are The Specific Effects Of The Fineness Of Micro Silica Fume (Silica Fume) On Concrete Properties?

The fineness of Ewende micro silica fume has various effects on the performance of concrete.

The fineness of Ewende micro silica fume has various effects on the performance of concrete:

Ease of use

- As the micro silica powder is very fine, it has a large specific surface area. In the process of concrete mixing, silica fume particles can fill the gaps between the cement particles, playing the role of ball bearings, so that the fluidity of the concrete mix is improved.

- However, if the micro silica powder is too fine, its large specific surface area will adsorb more free water, resulting in increased cohesion and reduced fluidity of the concrete mix, which may be dry and difficult to vibrate.

Strength

- Extremely fine micro silica powder can fill the tiny pores in the concrete more effectively, making the concrete denser. During the hardening process of the concrete, the micro silica powder reacts with calcium hydroxide, a hydration product of cement, to produce more C - S - H (hydrated calcium silicate) gel, which improves the compressive and flexural strength of the concrete.

- The higher the fineness, the more obvious this filling and reaction effect usually is, which can significantly improve the early strength and late strength of concrete. For example, the use of high fineness micro silica powders can speed up the production cycle for some precast elements that require high early strength.

Durability

- High fineness micro silica powder can reduce the connecting pores inside the concrete and lower the permeability of the concrete. Aggressive media such as chloride ions and sulfate ions will be more difficult to enter the concrete interior, thus improving the concrete's resistance to chloride ion penetration and sulfate erosion.

- It also enhances the freeze-thaw resistance of concrete. Because of the reduced pore space, it reduces the internal stress caused by the expansion of water freezing during freeze-thaw cycles, making the concrete structure less prone to damage in harsh environments.