Efflorescence is a chalky white salt residue that can occur with any product containing cement. As moisture migrates up to the surface of the concrete, it carries along with it calcium salts from within the concrete.
Why is my concrete turning white? Efflorescence is a white salty residue caused when too much moisture is moving through the concrete. As the concrete dries and its moisture rises upwards through the slab, it brings salts within the concrete to the surface as well.
Efflorescence is the white powdery substance often seen on the surface of concrete or brick. Efflorescence is caused by water vapor migrating through the slab bringing soluble salts to the surface of the concrete. Many people mistake the white powdery substance with mold or mildew.
Although the bulk of the hydration process takes place in the hours and days immediately after the pour, concrete needs 28 days to fully dry. While the slab will harden and lighten in color before 28 days, don't be fooled into thinking it's done hydrating.
DO spray new concrete with water. Moist curing is a common method of concrete curing. It involves wetting the concrete slab often with water (5-7 times per day) for the first 7 days.
Answer: This is one of the most common but least understood phenomenons with concrete. Efflorescence is a chalky white salt residue that can occur with any product containing cement. As moisture migrates up to the surface of the concrete, it carries along with it calcium salts from within the concrete.
In many cases, efflorescence will disappear on its own over time (usually after the first year of a paver or retaining wall installation).
It is common for people to confuse mold with efflorescence. Efflorescence itself isn't dangerous or harmful. It can lead to potential moisture problems that can cause structural damage to building materials.
If your concrete has already cured and you are experiencing dusting use a concrete coating or concrete densifier to stop concrete floor dusting. Concrete dusting is usually a chalky white or gray dust coloring over the natural gray of concrete, leading to an unpleasant visual facade for your concrete.
By sealing with a penetrating concrete sealer, concrete is hardened up to 45% and efflorescence is eliminated. Since humidity can affect efflorescence, it has been shown that it can be a seasonal problem with efflorescence being most common during rainy seasons.
Vinegar and water solution—Efflorescence can be removed by using a dilute solution of household white vinegar and water. A vinegar and water solution is relatively inexpensive, non-toxic, and easy to obtain, mix and apply. Dilution ratio is 20–50% vinegar in water by volume.
Curing times for concrete
Technically, concrete never stops curing. In fact, concrete gets stronger and stronger as time goes on. But, as far as we're concerned, to reach a practical strength, most industrial concrete mixes have a 28 day curing period.
Efflorescence is a white deposit on concrete due to moisture loss. It's an issue that affects new concrete, in which sodium and sulfate chemicals from several hydroxides, minerals, chlorides and nitrates accumulate on the surface and pores of the material.
Perhaps the most tell-tale sign of shoddy concrete pouring is the presence of cracks. The primary cause of cracks in dried concrete is tensile stress on the structure.
Efflorescence alone does not pose a major problem, but it can be an indication of moisture intrusion, which may compromise the structural material. Building materials, such as concrete, wood, brick and stone, are porous materials. Porous materials can absorb or wick water by a process called capillary action.
As stated previously, most efflorescing salts are water soluble and many will disappear with normal weathering unless there is some external source of salts. In general, most efflorescence can be removed by dry-brushing followed by flushing with clean water.
Unless something else is done, the efflorescence will be back soon. In order to prevent it, you'll need to: Eliminate soluble salts for your concrete or masonry, and/or. Prevent water from transporting soluble mineral salts to the surface.
RadonSeal Efflorescence Cleaner can be safely used on poured concrete, concrete blocks, bricks, stucco, pavers, and artificial stones. The cleaner chemically breaks down and removes efflorescence, lime deposits, metal salt stains, and rust deposits.
Pressure washing can work to remove white efflorescence once the surface has thoroughly dried. The surface must be thoroughly rinsed to ensure that no residue remains. We also use a safe detergent to ensure a thorough clean.
The white powdery substance is efflorescence, and you want to neutralize it with DRYLOK Etch which is much safer than muriatic acid. Above all, remove efflorescence prior to waterproofing to avoid the waterproofer from failing.
Painted surfaces already damaged by efflorescence must NOT be repainted until the source of the moisture is identified and eliminated or blocked (by waterproofing). It may be necessary to engage the services of a qualified waterproofing specialist.
Efflorescence occurs when water soluble salts travel to the concrete surface. The mineral salts might be a result of the cement hydration reaction or can come from many other sources like sulphate rich sand. Porous concretes, masonry and mortars will be more susceptible to the migration of salts to the surface.
First, for very mild cases of efflorescence, try a 50/50 mix of white vinegar and water. Using a scrub brush, spot treat and scrub affected areas with the vinegar mix. The acidity in the vinegar helps remove the efflorescence and calcium deposits by breaking down mineral crystals.
Concrete that is not moist-cured at all dries too rapidly, and reaches less than half its potential design strength. It will also have a greater number of shrinkage cracks.