Colloidal silica reduces reinforcing steel corrosion

By Carl White

United States-based Spray-Lock Concrete Protection’s colloidal silica post-placement pozzolan technology reduces reinforcing steel corrosion in concrete.

Reinforced concrete remains one of the most widely used construction practices since the late-1800s. This is considering the role that reinforcing play in helping to strengthen concrete in tension.

Colloidal silica enhances reinforced concrete performance

Colloidal silica post-placement pozzolan technology enhances reinforced concrete performance. This is by successfully addressing the biggest challenge in terms of the use of this construction practice, namely reinforcing corrosion. It remains the leading cause of failure of reinforced concrete structures.

The corrosion of reinforcing steel is an electrochemical reaction. This reaction consists of the flow of electrons and ions that deteriorates the steel and its properties. One significant way of reducing the corrosion potential of reinforcing bar is to completely encapsulate it in concrete with a high pH value. This high alkaline environment acts as a protective oxide film. If no other outside forces are applied to the reinforced concrete, the steel should not rust. Unfortunately, however, almost all reinforced concrete is exposed to environmental conditions that shorten its lifespan by increasing corrosion potential.The corrosion potential of reinforcing steel is influenced by several factors. They include moisture intrusion; reduced pH values over time; and quality of the concrete and construction materials. This is in addition to proper concrete coverage of reinforcing steel; initial curing conditions; and the formation of cracks in the concrete. These factors can accelerate contaminants movement. This disrupts the protective oxide film around the reinforcing steel which leads to corrosion. In turn, corrosion can result in spalling and delamination of the concrete structure.

Colloidal silica penetrates concrete

Colloidal silica post-placement pozzolan technology penetrates the pores and bleed-water capillaries in concrete. It has the capacity to raise the pH of older concrete and stabilise the pH value of new concrete. This action reduces the potential of reinforcing steel corrosion.

Colloidal silica waterproofs concrete

Furthermore, our colloidal silica post-placement pozzolan technology waterproofs concrete within concrete cover. It also does so in the application area when there are no cracks in existing reinforced concrete. SCP fills the capillary and pore space with calcium silicate hydrate (C-S-H) as it reacts with available alkalis. Preventing the migration of moisture that carries chlorides into the concrete matrix also reduces reinforcement corrosion potential.

Colloidal silica post-placement technology

Spraylock Africa is the African distributor of Spray-Lock Concrete Protection’s cutting-edge colloidal silica post-placement pozzolan technology.

Located in Johannesburg, Gauteng, South Africa, Spraylock Africa is headed by Carl White.

His team continues to stand by SCP solutions, which are built upon unique technology with a more than 35-year-long track record in the market. This is in addition to a team of experienced and skilled people who are passionate about and dedicated to solving their clients’ unique concrete challenges.