Efflorescence In Concrete: Causes & Prevention

If the building is built of brick, tiles, concrete, or other masonry materials, efflorescence is a frequent problem that most residential and commercial buildings encounter. It creates aesthetic issue to house or commercial structure, but you can repair it.

What is efflorescence in concrete?

When a white or grayish-tinted powder appears on the surface of concrete, it is referred to as efflorescence. It gathers on the concrete, is formed of crystallised salt, and remains there even after the water has evaporated. Additionally, special care is required for treating concrete efflorescence.

Efflorescence on concrete surfaces: Why does it occur?

One or more of the components of concrete generally contain salts. When the water-to-cement ratio is high, concrete becomes more porous, enabling salt solution and water to pass through. It’s likely that insufficient curing caused the product to become dehydrated close to the concrete’s surface.

Salts are brought to the concrete surface by moisture and permitted to build there as water evaporates. Low water evaporation means that salts are penetrating the surface of the concrete. Water can seep through concrete more easily when there is more variation in the concrete during the mixing, curing, and compacting stages.

How can remove the efflorescence-affected concrete surfaces?

Method 1- By Using Hard Brush

Concrete efflorescence or soluble slats can be eliminated from surface deposits of concrete with a hard, stiff-bristle broom or brush. However, clean water should be used to scrub the concrete’s surface before gently washing it if the results of dry brushing are occasionally unsatisfactory.

Because accumulated insoluble salts that are white in colour, hard, scaly, or crusted cannot be removed by softly cleaning with water, efflorescence is cleaned with a high-pressure water jet.

Method 2-By Using Dilute Acid Solution

Applying a diluted acid solution is usually more efficient, and in some cases, as will be shown below, it might even be the only choice. Extreme care must be taken while handling chemical solutions; when diluted hydrochloric acid, acid is always added to water rather than the other way around. To clean the concrete’s surface, only diluted chemical solutions or acids were used.

The suggested ratio is 1:20, or one component hydrochloric acid to twenty parts waters. The surface is first thoroughly wetted with water before applying this dilute acid solution. Before applying the solution, make sure the surface is moist but clear of any free water. The chemical mixture should be given 10 to 15 minutes to react on the concrete surface. Clean water was used to gently rinse and scour the surface. Wash at least three more times, or until no signs of the chemical solution remain. When applying a chemical or acid rinse to a color-finished surface, you should dilute the solution to 2%, which is 1 part acid to 50 parts waters.

How to prevent efflorescence in concrete?

Keeping water from seeping through the wall is the best approach to stop efflorescence. Diverting water can stop internal water seepage, but this may not completely eliminate the issue of efflorescence and other moisture-related mineral buildups. Whatever you do on the inside, water may still be leaking from the outside through the wall. If efflorescence crystals appear, there is likely a leak that allows water from the outside to enter. Hence, waterproofing of the outside walls should be considered.

And as was already mentioned, water—either from above or below a slab—is what triggers the efflorescence reaction. Only vapour barriers can stop moisture from moving from the subgrade to a slab’s surface. Additionally, the use of coatings and sealants helps stop surface water from infiltrating slabs.

Key Takeaways

Efflorescence is a sign of various forms of water damage. When you first notice efflorescence, the building has already begun to suffer harm from water. Efflorescence is an indication to start a repair work. The best protection against efflorescence and water damage is to waterproof the surface entirely from outside.

Please do not hesitate to contact us if you require more information. Our team will be happy and glad to assist you.

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