Colloidal Silica in the Cement Industry


Colloids play an important role in various industries, ranging from cosmetics to pharmaceuticals. We have all encountered them throughout our daily lives in the form of whipped creams, hairsprays, and hair-styling mousses. One industry that benefits from the unique properties of colloids is the cement industry.

Keep reading to learn more about how colloids are used in the cement industry.

What Are Colloids?

Colloids are stable suspensions of microscopic particles or molecules evenly dispersed throughout a dispersion medium. Unlike other suspensions, colloids do not separate or settle, making them a unique category with diverse applications.

What Is Colloidal Silica?

Colloidal silica is a specialized type of colloid where silica molecules are evenly dispersed in a liquid medium. It is meticulously produced to ensure stability, preventing the formation of unstable silica gels. With its low viscosity and high fluidity, colloidal silica offers remarkable versatility and can be tailored based on factors like particle size, pH, ionization, and surface charge.

Brief History

The use of colloidal silica in the cement industry has gained significant attention and recognition. Studies conducted by the US Army Corp. of Engineers back in the early 2000s paved the way for its widespread application. Both the academic and construction sectors have observed that colloidal silica has the potential to enhance the strength and durability of concrete.

Applications in the Cement Industry

In the cement industry, colloidal silica has been widely utilized as a concrete densifier, delivering consistent and reliable results for concrete polishers and other professionals seeking to strengthen and densify cured concrete surfaces.

Advantages of Colloidal Silica

The objective of all concrete densifiers is to introduce a reactive form of silica into the microscopic pore system of cement paste, utilizing a liquid as a carrier.

Densification and Strength Enhancement

Colloidal silica provides virtually pure silica in nanoparticles that can effectively penetrate the pore structure. The low surface tension of the liquid enables the particles to reach below the surface. With a higher proportion of reactive sites compared to silicates, pure silica particles exhibit exceptional reactivity.

Within the pores, colloidal silica generates new calcium silicate hydrate (CSH) that bonds with the existing CSH while also forming direct bonds with other silica particles. This results in a cascade of reactions, with the bonded silica serving as a platform for further bonding. Silicate densifiers, on the other hand, lack this capability.

Surface Protection and Hardening

Scientists have rigorously tested colloidal silica in laboratories and field applications using the same methods employed for other densifiers. It proves effective in hardening for polishing and other floor-finishing operations, eliminating dusting and improving abrasion resistance. As a clean and eco-friendly densifier, it also minimizes labor.

Apart from extending the finishing time and simplifying the finishing process, it eliminates the need for excessive water addition to achieve a smooth surface, resulting in a slab that possesses the intended hardness as specified in the mix design.


At Qemi International, we are proud to offer high-quality and customizable colloidal silica products. Contact us today to learn how we can help you meet your industry’s needs!