Efflorescence (full explanation )

 #Efflorescence:-

एफ्लोरेसेंस नमक का एक क्रिस्टलीय जमा होता है जो ईंट, कंक्रीट, पत्थर, प्लास्टर या अन्य भवन सतहों पर या पानी मौजूद होने पर बन सकता है।  इसमें एक सफेद या भूरा रंग होता है और इसमें नमक जमा होता है जो पानी के वाष्पीकरण के बाद सतह पर रहता है।

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Efflorescence:-

Efflorescence is a crystalline deposit, usually white, that maydevelop on the surfaces of masonry construction (see Fig. 1).Often it appears just after the structure is completed—when builder, architect, and owner are most concerned with the appearance of the new structure. Although unattractive, efflorescence isgenerally harmless. However, some forms (alkali carbonates) maybe able to saponify paints, leading to failure of the paint-masonry bond. Other deposits can occur within the surface pores of thematerial, causing expansion that may disrupt the surface. This condition is sometimes termed cryptoflorescence.This information sheet examines the causes, prevention, andremoval of efflorescence encountered on masonry surfaces.

Formation of white patches on the surface of bricks due to the presence of insoluble salts in the clay used for making bricks.

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The presence of efflorescence, if any, is classified as under:

 (a) No efflorescence: If the deposit of efflorescence is imperceptible. 

(b) Slight efflorescence: When the efflorescence doesnot cover 10% of the exposed area of the brick. efflorescence is more than 10% but less than 50% of the exposed area and the deposit does not

(c) Moderate efflorescence : When thepowder or flake the surface. 

(d) Heavy efflorescence: When the efflorescence covers 50% or more area but the deposit does not or flake the surface.powder 

(e) Serious efflorescence: When the deposit of efflorescence salts is heavy and is accompanied bypowdering and/or flaking of the exposed surfaces.

(ईंटों को बनाने के लिए उपयोग की जाने वाली मिट्टी में अघुलनशील लवणों की उपस्थिति के कारण ईंटों की सतह पर सफेद धब्बे बनना।) 👇

https://youtu.be/aVRFOe5ri3w

Causes

A combination of three common circumstances causes efflorescence:

• soluble compounds in the masonry or adjoining materials

• moisture to pick up the compounds and carry them to the surface

• evaporation or hydrostatic pressure that causes the solution to move

Prevention

Since many factors influence the formation of efflorescence, it is difficult to predict if and when any will appear: There is no accepted standard test method for measuringtheefflorescencepotential of masonry mortar. Several experimental methods havebeen proposed, but none has been accepted as effectively predicting the performance of mortar materials in actual use.

ASTM C 67 does include an efflorescence test for clay brick. 

The test is helpful in indicating whether or not clay units will 

effloresce by themselves when exposed to moisture. However, 

it does not address the potential for efflorescence resulting fromcement-brick reactions or other external conditions that oftenoccur in service.

Given the characteristics of masonry materials and construc-tion, it is virtually impossible to eliminate all the soluble salts, construct walls containing no free moisture, or completely eliminate paths of moisture migration. However, steps can betaken to minimize the extent of these three contributing factors.

Good workmanship is one of the most effective means of limiting

the potential for efflorescence.

Most efflorescence can be classified as temporary. Often termed

"new building bloom," indicating its link to the exposure 

conditions and excess moisture that accompany new masonry 

construction, it is harmless and should not cause undue concern.

On the other hand, recurrent efflorescence indicates a chronic

moisture problem. Efforts should be taken to correct the moisture

problem, thereby preventing and eliminating recurrent efflorescence. 

The following recommendations are targetedtoward that goal:

Provide for good drainage

— Correctly install waterstops, flashing, weepholes, and cop-

ings per design details. Maintain clean cavities and unob-

structed weepholes during the construction of cavity walls.

Construct good mortar joints

— Tool all mortar joints with a V- or concave-shaped jointer to

compact the mortar at the exposed surface and create a tight

bond between mortar and masonry unit Weeping, raked, and untooled struck joints are not recommended in exposed applications.

— Assure that joints are properly filled. Deteriorated or defec-tive mortar joints should be repointed to keep moisture outof the wall.

Ensure proper curing

— Assure adequate hydration of cementitious materials by 

protecting masonry from cold temperatures, premature 

drying, or improper use of admixtures.

Limit water entry

— Apply paint or other proven protective treatment to the 

outside surfaces of porous masonry units. Caulk around 

window and door openings. Seal or otherwise repair cracked

joints in walls. Also, use through-wall flashing at ground level to prevent capillary rise of ground moisture.

— Install vapor barriers in exterior walls (interior surfaces of

exterior walls) or apply vaporproof paint to interior surfaces

and use designs that minimize condensation within masonry.

— Carefully plan the installation of lawn sprinklers or any 

other water source so that walls are not subjected to unnecessary wetting.

— If feasible, use wide overhanging roofs to protect walls from rainfall.

Removal

Since efflorescence often occurs during or right after construction,the first impulse is to immediately wash it off with water or 
a masonry cleaning solution. This is not advisable, particularly in cool or cold damp weather, when the RemovalSince efflorescence often occurs during or right after construction,the first impulse is to immediately wash it off with water or a masonry cleaning solution. This is not advisable, particularly in cool or cold damp weather, when the primary result of suchaction will be to introduce more water into the masonry wall.
Given time, efflorescence will often disappear by itself or at mostmay require mild cleaning measures such as dry brushing or rinsing and brushing with a stiff brush. If this does not producesatisfactory results, it may be necessary to wash the surface witha proprietary masonry cleaning solution or a very dilute solutionof muriatic acid (1% to 10%). In any case, prior to removingefflorescence from a surface, the surest way to establish an appropriate cleaning procedure is to chemically identify thedeposit (see table on next page). Following cleaning, the wallshould be thoroughly rinsed with clean water to remove all traces of the cleaner Prior to using a proprietary cleaneror muriatic acidsolution, the cleaning agent’s
compatibilty with the masonry unitsshould be verified with the manufacturer of the units.Where integrallycolored concretemasonry units or mortars areinvolved, use only a 1% to 2% acid solution or a proprietarycleaner specificallyrecommended for that application. In any event, careshould be taken tprimary result of such action will be to introduce more water into the masonry wall.

Removing Some Forms of Efflorescence

Common compound Recommended cleaning method

Alkali sulfate Stiff brush. If necessary, brush with water.

Calcium sulfate Stiff brush. If chronic, add water washing.

Calcium carbonate Stiff brush if not adherent. 

If adherent, apply dilute acid or proprietary cleaning 

solution to dissolve efflorescence.