Reinforcing Effects
As one of the active mineral admixtures used in concrete, Ewende micro silica improves the composition of cementitious materials upon incorporation, particularly by reducing and eliminating free lime. The SiO₂ in the active minerals undergoes pozzolanic reactions with free lime and highly alkaline calcium silicate hydrates, forming low-alkali calcium silicate hydrates with superior strength and stability. This significantly increases the volume of cementitious material and substantially improves the interface structure between the cement paste and aggregates. Consequently, concrete strength is greatly enhanced. This represents the strengthening effect of silica fume on concrete.
Filling Effect
When an appropriate amount of ultrafine mineral admixture—micro silica (average particle size 0.10–0.26 μm)—is added to concrete, its average particle size is one order of magnitude smaller than that of fly ash and slag. Ewende Micro silica can further fill the voids between fly ash and slag particles, enhancing the compactness of cementitious particles and further increasing strength. Additionally, this filling effect improves concrete density, thereby enhancing durability.
Plasticizing Effect
Under the synergistic action of high-efficiency water-reducing agents during mixing, the surfaces of minute spherical micro silica particles become coated with surfactants. Similar to cement particles and other mineral admixture particles, this coating induces electrostatic repulsion between particles. Since spherical silica fume particles are significantly smaller than cement particles, they act as “ball bearings” between cement particles, increasing the fluidity of the cement paste. This facilitates pumping and placement, thus effectively demonstrating the enhancement effect.
Improved Concrete Durability
The incorporation of active silica fume generates substantial amounts of low-alkali calcium silicate hydrate (CSH) within the concrete hydration products. This CSH absorbs and immobilizes large quantities of Na⁺ and K⁺ ions, significantly reducing the effective alkali content in the pore solution of the concrete. Consequently, the detrimental effects of alkali-aggregate reactions are greatly diminished. Furthermore, silica fume fills voids between cement particles and at interfaces, substantially improving concrete impermeability. This prevents water and corrosive media from penetrating the concrete matrix, thereby significantly enhancing its durability.