How Silica Fume Reduces Production Costs of Cement Concrete

Adding 5- 10% of silica fume to cement products improves the strength and compactness of concrete. When producing cement products that meet specified strength grades, silica fume can reduce cement material costs and enhance product performance. Silica fume fills the voids between cement particles, reacts with hydration products to form gels, and also reacts with alkaline materials such as magnesium oxide to produce gel substances.

Adding an appropriate amount of silica fume to cement-based concrete, mortar and refractory castables yields the following effects:

• Significantly improve compressive, flexural, impermeable, anti-corrosive, impact-resistant and wear-resistant properties.

• Retain water, prevent segregation and bleeding, and greatly reduce the pumping resistance of concrete.

• Significantly extend the service life of concrete. Especially in harsh environments such as chloride salt erosion, sulfate attack and high humidity, the durability of concrete can be doubled or even increased several times.

• Greatly reduce the rebound loss of shotcrete and castables, and increase the single spraying thickness.

• It is an essential component of high-strength concrete and has been applied in projects producing C150 concrete.

• With an efficiency approximately five times that of cement, it can reduce costs and improve durability when used in ordinary concrete and low-cement castables.

• Effectively prevent alkali-aggregate reaction in concrete.

• Improve the compactness of castable refractories. When coexisting with Al₂O₃, it tends to form mullite phases, enhancing high-temperature strength and thermal shock resistance.

• It exhibits a strong pozzolanic effect. During concrete mixing, it undergoes secondary hydration with Ca(OH)₂, a cement hydration product, forming cementitious substances that fill the cement stone structure, refine the microstructure of the paste, and enhance the mechanical properties and durability of the hardened material.

• As amorphous spherical particles, silica fume improves the rheological properties of concrete.

• Silica fume has a small average particle size and excellent filling effect, filling voids between cement particles to improve concrete strength and durability.

• Silica fume particles are about 100 times smaller than cement particles. Filling the gaps between cement particles acts similarly to how cement fills gaps between aggregates, increasing the compactness of concrete.