If there is a problem in curing concrete, the hydration process remains incomplete. By which the un-hydrated products come out near the surface of the concrete.
Existent of salts in one of the materials of concrete. Generally, salts are mostly found in the fine aggregate or sand is taken out from the river beds.
The slow rate of evaporation of water proving more time to salts to come out on the surface (the main reason why efflorescence cases appeared to be more during the winter months, on another hand during summer, high temperatures may cause evaporation fast. Hence it has fewer chances to appeared on the surface).
The water used in the concrete mix is beyond the limit; it causes the concrete porous. Hence need to release extra water and salts to erupt on the surface and for efflorescence.
During wet weather conditions mainly in the rainy season, the excess water acts as a path for the salts to carry on the surface of concrete and form a white crystalline powder.
The variableness of concrete (curing or compaction) can result in localized problems where water can saturate more quickly through the concrete.
Installing a vapor obstacle to prevent the movement of moisture from the subgrade to the surface of a slab.
The involvement of Class-F fly ash or metakaolin can be fixed up considerable amounts of calcium hydroxide in the concrete.
The application of sealers and coatings can avoid surface water from penetrating to slabs.
Preventing the toughened concrete from exposure to moisture by maintaining surface sealers and site drainage, and from growing groundwater by placing a plastic membrane under slabs.
Waterproofing agents to be used to lessen permeability of concrete.
Making the concrete denser will decrease the permeability of concrete up to an immense extent.
Before taking steps to the removal of efflorescence in concrete, as an initial step, the resource for the reasons for the efflorescence must be found out and tried to alleviate it.
Furthermore, the removal of efflorescence can be done by mostly three adaptable methods,
Firstly, Efflorescence in the concrete can be easily removed by using the high-pressure water jet. Applying high-pressure water may dissolve efflorescence quickly.
However, care must need to be taken that the water after removing it is dried out. If it remains wet, the same water can create efflorescence on the surface.
Firstly, strict warning not to use Concentrated acid directly on concrete, the diluted proportion of 1:20 is used. The surface on which the acid will apply must be moist but without any water(on the cover).
Keep the applied solution on the affected area for 10 to 15 minutes. The surface should then be thoroughly washed and scrubbed with lots of clean water.
Do it again at least twice or until all traces of the acid solution have been removed from the surface.
Acid washing may cause shade variations, and surface texture may get changed. When acid washing is preferable on color finishes, prefer a diluted acid solution (2%,1 part acid to 50 parts water).
For the initial experiment, apply it to small areas to scrutinized its trial consequences.
Proper safety criteria must be followed while working with acids in this procedure. Ensure that the working area has sufficient ventilation and avoid direct touch between the acid and steel.
It is using high-quality concrete that contains minimal water. It is known as "low slump" concrete.
First, make sure the gravel and sand used in concrete have been washed further. More water used in this mixture is pure and salt-free.
Use low-alkali mortar for brickwork; hence, alkali salts don't pour into the masonry. Make sure that the chemical used in the manufacturing of fired bricks.
Consider a sealer or paint, which will give you limited efflorescence. Since some sealers can trap the deposits and make them harder to eradicate, all things are done under expert supervision to get exact positive consequences.