DAMAGE FACTORS FOR CONCRETE AND CEMENT

WATER

Penetrating water is concrete’s worst enemy. Water transports harmful elements like chlorine, sulfur and other acids. These, dissolves the binder in the concrete (lime leaching), lowers the pH of the concrete and causes reinforcement corrosion. The concrete whiters slowly and weakens the strength. Controll®Innerseal provide the concrete with high pH (11,5), reinforces the binder, silicates crystallize into concrete's pores and stop water seepage. The protection is diffusion and existing damp can evaporate.

CARBON DIOXIDE AND REINFORCING RUST

Carbon dioxide (CO2) that exists in the air reacts with lime and water in the concrete, that converts into calcium carbonate (carbonation). In this process, the pH-value is reduced and the concrete decomposes. A ‘healthy’ concrete has a pH-value between 12-13. If the value is reduced to less than 9,5, forms corrosion attacks on the reinforcement, which in turn expands and breaks the concrete. Controll®Innerseal block water penetration, stops pH-reduction and reinforcement rust.

FROST

When seawater freezes in the concrete, it expands by 9% and severe tensions occurs. In combination with a weakening (eg leaching) there is a risk of the concrete breaks. Worse it becomes when the water freezes and melts alternately. When adding salt (e.g. from sea or road salt) increases the volume expansion when freezing with > 15%. In result, there is a escalating damage process with cracks and constrictions. Controll®Innerseal prevents penetration of water and terminates the damage process.

SALT PRECIPITATIONS

White spots on the surface of the concrete is a clear sign of an ongoing leaching process caused by water. Water resolves salt and lime within the concrete that is transported in the concrete’s capillary system to the surface. When the water evaporates salt and lime remains. Controll®Innerseal effectively bind up the line in the concrete, block the concrete’s capillary system against water and stop leaching.

ALKALI-SILIKA REACTIONS (ASR)

ASR occurs by alkalireaktiv ballast comes in contact with alkalis contained in the cement paste pore solution and forms a viscous gel. When absorbing water, the gel expands which can result in the concrete breaking. When the original problem is due the wrong ballast (reactive rock) being used, there is no definitive solution to the problem. Though, by impregnating with Controll®Innerseal water penetration is prevented and the damage process is significantly delayed.

ACID RAIN

Airborne pollution is one of the greatest causes of degradation of concrete. Sulfur dioxide (SO2), water and oxygen forms sulfuric acid. Sulfuric acid reacts with calcium in the concrete and converts to calcium sulfate, which creates a thin membrane on the concrete surface. Behind this membrane is an ongoing decomposition process where the cement crumbles and pulverizes. Controll®Innerseal creates both a profound acid-resistant protection in the concrete and prevents liquids from entering.

SEAL COATINGS AND PAINTS

In order to prevent penetration of water and harmful liquids, diffusion-tight membrane coatings like bitumen and epoxy is commonly used. If there is a risk of rising damp from underneath (e.g. floor plate) there is also a high risk that delamination and gas bubbles occur. In case the dense coating is damaged by stroke or abrasion, water and hazardous liquids may penetrate which can not be vented. The high damp levels sustained in the concrete, contributes to a latent escalating damage process. Controll®Innerseal creates a diffusion and integrated protection of the concrete which is insensitive to rising damp and highly resistant to strokes and abrasion. Additionally, the surface is inspectable and enables local repairs with minimal preparation.