Extend the life of your concrete structure with MasterProtect 8500 CI

Corrosion is always lurking. Especially in the case of concrete with steel reinforcement, the proper method must be followed to reduce and prevent corrosion. Corrosion can be defined as the transformation of a refined metal into its more stable oxides by the attack of oxygen and water.

Concrete provides a natural shield that protects the steel reinforcement from corrosion. The highly alkaline environment created by the cement matrix around the steel reinforcement forms a passive layer around the bar, specifically an impermeable oxide layer that prevents further corrosion by completely insulating the steel surface.

However, this protective layer is only maintained as long as the high alkaline environment of the concrete matrix persists. Carbonation because of exposure to carbon dioxide dissolved in water reduces the pH of the cement matrix. In addition, chloride ions also disrupt the passive layer and lead to corrosion. When the passive layer breaks, corrosion reactions occur that damage the steel reinforcement.

Inhibit corrosion process

Although the corrosion process cannot be avoided, a lot can be done to slow down the process. There are several types of corrosion inhibitors on the market. They consist of chemical compounds that prevent corrosion reactions on the reinforcing steel. All inhibitors must get close to the steel reinforcement in the concrete to protect it. Therefore, corrosion inhibitors can be added to concrete admixtures and mixed directly with the fresh concrete or applied to the surface of the cured concrete (surface-applied corrosion inhibitors). The first type of corrosion inhibitors can only be applied to new structures; the second type is specifically designed for the renewal of existing structures.

State-of-the-art protection for steel reinforcement

No more choosing between the perfect solution for new or existing structures. MasterProtect 8500 CI from Master Builders Solution is a new corrosion inhibitor that was developed for application to new and existing structures and has proven effective even with post-coating cracks. MasterProtect 8500 CI is a dual-function silane-based corrosion inhibitor that is applied to the surface. The inhibitor is suitable as part of a corrosion prevention, corrosion protection or corrosion inhibition strategy. It is a revolutionary blend of high-performance silanes with selective corrosion inhibitors, which are dormant in the concrete until activated by moisture penetrating the surface due to cracking or aging of the concrete.

The inhibitor cannot be noticed by eye when dry, as MasterProtect 8500 CI does not change the appearance of the concrete. However, when the concrete is wet, the water repellency, the pearl effect, on the concrete surface can be easily observed. In addition, MasterProtect 8500 CI has a very low viscosity that improves penetration into the concrete at a wide temperature range, a lower VOC content and a higher flash point. All this combined makes product handling and application much easier and safer than many other inhibitors.

MasterProtect 8500 CI applied in a parking garage.

What do we mean by dual effect and how does it work?

With conventional corrosion inhibitors applied to the surface, the inhibitor must penetrate deep into the concrete to reach the steel reinforcement. There, the functional group acts directly on the surface of the bars and again passivates the steel and reduces active and future corrosion. MasterProtect 8500CI goes one step further with its dual action.

The dual action of MasterProtect 8500 CI consists, on the one hand, of the water-repellent effect of the high-quality mix of silanes, which prevents moisture and chlorides from penetrating the concrete. Depending on the chemical reaction that takes place, silanes with different functions can be created. MasterProtect 8500CI uses multiple silane functions to create different effects on the concrete substrate. These include a corrosion-inhibiting effect and the formation of a water-repellent layer that protects the concrete from liquid penetration, but allows water vapor to pass through. Thus, new moisture cannot penetrate the concrete, but moisture that may be in the substrate can evaporate.

This phenomenon causes the concrete to be constantly dry and increases its electrical resistance. Since concrete can be considered an electrolyte for steel reinforcement, higher resistance prevents electrochemical reactions. In dry and alkaline concrete, the steel reinforcement is also rapidly passivated. Thanks to the lack of water and the high resistance of the concrete, the corrosion rate is drastically reduced.

The steel reinforcement remains protected

The dormant inhibitor is mixed with the silanes of the second element of the dual action of MasterProtect 8500 CI. The presence of dormant inhibitors is crucial to the long-term protection of reinforced concrete structures against corrosion. It is very likely that structures will crack at some point, regardless of the age and quality of the concrete. Concrete with steel reinforcement tends to crack for several reasons. Cracking also means that the water-repellent shield of the silanes of MasterProtect 8500 CI is no longer effective. Water ions and chloride ions can penetrate through the crack and cause damage to the steel reinforcement. This is where the dual action comes into play and MasterProtect 8500 CI continues to protect the reinforcement. The latent inhibitors remain dormant in the concrete until the hydrophobic properties diminish over time or the concrete cracks. Then they are activated, become mobile and are carried deeper into the concrete by the moisture. Thus, the steel reinforcement remains protected.

MasterProtect 8500 CI distinguishes itself from the many existing inhibitors on the market thanks to its dual action: in addition to the water-repellent shield created by the revolutionary mix of silanes, the dormant inhibitor provides long-term protection. This allows the life span of all types of reinforced concrete structures to be extended. The effect has been demonstrated by several independent tests.