266:, when water moving through a wall or other structure, or water being driven out as a result of the heat of hydration as cement stone is being formed, brings salts to the surface that are not commonly bound as part of the cement stone. As the water evaporates, it leaves the salt behind, which forms a white, fluffy deposit, that can normally be brushed off. The resulting white deposits are referred to as "efflorescence" in this instance. In this context efflorescence is sometimes referred to as "saltpetering." Since primary efflorescence brings out salts that are not ordinarily part of the cement stone, it is not a structural, but, rather, an aesthetic concern.
529:
463:
505:
129:
517:
447:
487:
300:
aggregates, colorants, and cement are added, followed by water. If CSD is used, it is then introduced usually at this point during or after the addition of the mix water. CSD is an aqueous dispersion wherein fine solid particles of calcium stearate are suspended in the water uniformly. Commercially available CSD has an average particle size of about 1 to 10 micrometres. The uniform distribution of CSD in the mix may render the resulting
336:
32:
435:
can occur from water being trapped inside the brick substrate and freezing during cold weather. Years ago, the water repellents trapped moisture in the masonry wall creating more problems than they solved. Condensation in areas that experienced the four seasons were much more problematic than their counterparts.
434:
Today's water repellents help create a vapor permeable barrier; liquid water, especially from wind driven rains, will stay out of the brick and masonry. Water vapor from the interior of the building, or from the underside of pavers can escape. This will reduce efflorescence, spalling and scaling that
420:
It is also possible to protect porous building materials such as brick, tiles, and concrete against efflorescence by treating the material with an impregnating, hydro-phobic sealer. This is a sealer that repels water and will penetrate deeply enough into the material to keep water and dissolved salts
152:
to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water or occasionally, in another solvent. The water, with the salt now held in solution, migrates to the surface, then evaporates, leaving a coating of the salt.
269:
For controlling primary efflorescence, formulations containing liquid fatty acid mixtures (e.g., oleic acid and linoleic acid) have commonly been used. The oily liquid admixture is introduced into the batch mix at an early stage by coating onto the sand particles prior to the introduction of any mix
278:
Secondary efflorescence is named such as it does not occur as a result of the forming of the cement stone or its accompanying hydration products. Rather, it is usually due to the external influence of concrete poisons, such as chlorides. A very common example of where secondary efflorescence occurs
160:
Efflorescences can occur in natural and built environments. On porous construction materials it may present a cosmetic outer problem only (primary efflorescence causing staining), but can sometimes indicate internal structural weakness (migration/degradation of component materials). Efflorescence
590:
299:
dispersion (CSD) are often added at a later stage of the batching process with the mix water. In a typical batching process, sand is first charged into the mixer, then the oil-based primary anti-efflorescence admixture is added with constant mixing to allow the oil to coat the sand. Then coarse
279:
is steel-reinforced concrete bridges as well as parking garages. Saline solutions are formed due to the presence of road salt in the winter. This saline solution is absorbed into the concrete, where it can begin to dissolve cement stone, which is of primary structural importance. Virtual
156:
In what has been described as "primary efflorescence", the water is the invader and the salt was already present internally, and a reverse process, where the salt is originally present externally and is then carried inside in solution, is referred to as "secondary efflorescence".
424:
Efflorescence can often be removed from concrete using phosphoric acid. After application the acid dilution is neutralised with mild diluted detergent, and then well rinsed with water. However, if the source of the water penetration is not addressed efflorescence may reappear.
283:
can be formed in some cases as a result of dissolved cement stone, hanging off cracks in concrete structures. Where this process has taken hold, the structural integrity of a concrete element is at risk. This is a common traffic infrastructure and
416:
particles and ultimately become part of the cement or sand with which they react. And since they require the presence of hydrogen they stop reacting as the concrete dries out and begin reacting again when the concrete is exposed to moisture.
421:
well away from the surface. However, in climates where freezing is a concern, such a sealer may lead to damage from freeze/thaw cycles. And while it will help to protect against efflorescence, it cannot permanently prevent the problem.
528:
615:
Smith, G K., (2015). "Calcite Straw
Stalactites Growing From Concrete Structures". Proceedings of the 30th 'Australian Speleological Federation' conference, Exmouth, Western Australia, edited by Moulds, T. pp 93
462:
310:
is also a secondary deposit derived from concrete, mortar or lime, which can be mistakenly assumed to be efflorescence. Calthemites are usually deposited as calcite which is the most stable
428:
Common rebar protective measures include the use of epoxy coating as well as the use of a slight electrical charge, both of which prevent rusting. One may also use stainless steel rebar.
504:
585:, Walloch, Craig T.; Ebner, Cynthia L. & Chin, David et al., "Masonry admixture and method of preparing same", published 1995-10-24, assigned to
431:
Certain cement types are less resistant to chlorides than others. The choice of cement, therefore, can have a large effect upon the concrete's reaction to chlorides.
222:
O) is a blue crystalline solid that when exposed to air, slowly loses water of crystallization from its surface to form a white layer of anhydrous copper(II) sulfate.
412:
in these additives can be up to 100,000 times smaller than even the smallest cement particles, allowing their molecules to literally pass through cement minerals or
408:
on a nanomolecular level, converting it into non-sodium chemicals and other harmless matter that will not leach out or migrate to the surface. In fact, the
486:
396:
The only way to completely and permanently prevent (both primary and secondary) efflorescence in cementitious materials is by using special
446:
383:
115:
304:
water repellent, as CSD particles are well distributed in the pores of the unit to interfere with the capillary movement of water.
161:
may clog the pores of porous materials, resulting in the destruction of those materials by internal water pressure, as seen in the
516:
254:
Primary efflorescence is named such, as it typically occurs during the initial cure of a cementitious product. It often occurs on
311:
133:
361:
357:
53:
49:
96:
68:
632:
603:
Smith, G.K. (2016). "Calcite straw stalactites growing from concrete structures", Cave and Karst
Science 43(1), 4-10.
346:
75:
186:) to form an NaCl cube by the mechanism of homogeneous nucleation. The original water is released to the gas phase.
365:
350:
42:
200:
O) is a hydrate solid that, in a sufficiently dry environment, will give up its water to the gas phase and form
473:
82:
128:
64:
301:
582:
586:
477:
175:
211:
20:
637:
469:
315:
270:
water, so that the oily admixture is distributed uniformly throughout the concrete batch mix.
263:
642:
493:
296:
225:
149:
89:
405:
179:
409:
626:
400:
that chemically react with and bind the salt-based impurities in the concrete when
289:
604:
335:
31:
559:
549:
307:
280:
295:
For controlling secondary efflorescence, admixtures containing aqueous-based
201:
141:
404:(H) is present. The chemical reaction in these special additives fuses the
510:
Secondary efflorescence - dissolving the cement stone and attacking rebar
401:
397:
285:
554:
453:
255:
148:(which roughly means "the flowering" in French) is the migration of a
189:
183:
259:
162:
127:
534:
Concrete derived secondary deposit of calcium carbonate creating
413:
329:
25:
182:
will spontaneously crystallize at 45% relative humidity (298
19:"Effloresce" redirects here. For the album by Oceansize, see
288:
maintenance concern. Secondary efflorescence is akin to
16:
Migration of a salt to the surface of a porous material
538:, which can be mistakenly confused with efflorescence.
492:Substantial primary efflorescence on a building in
56:. Unsourced material may be challenged and removed.
605:http://bcra.org.uk/pub/candks/index.html?j=127
8:
364:. Unsourced material may be challenged and
132:Secondary efflorescence on the dam of the
452:Primary efflorescence on a brick wall in
384:Learn how and when to remove this message
116:Learn how and when to remove this message
577:
575:
571:
500:
442:
240:O) will lose water when exposed to air.
7:
362:adding citations to reliable sources
54:adding citations to reliable sources
14:
527:
515:
503:
485:
461:
445:
334:
326:Protecting against efflorescence
134:Robert Moses Niagara Power Plant
30:
41:needs additional citations for
1:
468:Primary efflorescence on a
258:construction, particularly
659:
18:
474:Mississauga Civic Centre
522:Secondary efflorescence
274:Secondary efflorescence
536:calthemite stalactites
137:
587:W. R. Grace & Co.
302:concrete masonry unit
250:Primary efflorescence
131:
478:Mississauga, Ontario
358:improve this section
50:improve this article
178:aqueous droplet of
176:molar concentration
633:Chemical processes
262:, as well as some
212:Copper(II) sulfate
138:
21:Effloresce (album)
394:
393:
386:
316:calcium carbonate
292:of the concrete.
214:(bluestone) (CuSO
126:
125:
118:
100:
650:
617:
613:
607:
601:
595:
594:
593:
589:
579:
531:
519:
507:
494:Denver, Colorado
489:
465:
449:
389:
382:
378:
375:
369:
338:
330:
297:calcium stearate
264:firestop mortars
226:Sodium carbonate
121:
114:
110:
107:
101:
99:
58:
34:
26:
658:
657:
653:
652:
651:
649:
648:
647:
623:
622:
621:
620:
614:
610:
602:
598:
591:
581:
580:
573:
568:
546:
539:
532:
523:
520:
511:
508:
497:
490:
481:
470:firestop mortar
466:
457:
450:
441:
406:sodium chloride
390:
379:
373:
370:
355:
339:
328:
321:
276:
252:
247:
239:
235:
231:
228:decahydrate (Na
221:
217:
207:
199:
195:
171:
122:
111:
105:
102:
65:"Efflorescence"
59:
57:
47:
35:
24:
17:
12:
11:
5:
656:
654:
646:
645:
640:
635:
625:
624:
619:
618:
608:
596:
570:
569:
567:
564:
563:
562:
557:
552:
545:
542:
541:
540:
533:
526:
524:
521:
514:
512:
509:
502:
499:
498:
491:
484:
482:
467:
460:
458:
451:
444:
440:
437:
410:nanotechnology
392:
391:
342:
340:
333:
327:
324:
319:
275:
272:
251:
248:
246:
243:
242:
241:
237:
233:
229:
223:
219:
215:
209:
205:
197:
193:
187:
170:
167:
124:
123:
38:
36:
29:
15:
13:
10:
9:
6:
4:
3:
2:
655:
644:
641:
639:
636:
634:
631:
630:
628:
612:
609:
606:
600:
597:
588:
584:
578:
576:
572:
565:
561:
558:
556:
553:
551:
548:
547:
543:
537:
530:
525:
518:
513:
506:
501:
495:
488:
483:
479:
475:
471:
464:
459:
455:
448:
443:
439:Image gallery
438:
436:
432:
429:
426:
422:
418:
415:
411:
407:
403:
399:
388:
385:
377:
374:November 2013
367:
363:
359:
353:
352:
348:
343:This section
341:
337:
332:
331:
325:
323:
317:
313:
309:
305:
303:
298:
293:
291:
287:
282:
273:
271:
267:
265:
261:
257:
249:
244:
227:
224:
213:
210:
203:
191:
188:
185:
181:
177:
173:
172:
168:
166:
164:
158:
154:
151:
147:
146:efflorescence
143:
135:
130:
120:
117:
109:
106:November 2020
98:
95:
91:
88:
84:
81:
77:
74:
70:
67: –
66:
62:
61:Find sources:
55:
51:
45:
44:
39:This article
37:
33:
28:
27:
22:
611:
599:
535:
433:
430:
427:
423:
419:
395:
380:
371:
356:Please help
344:
306:
294:
290:osteoporosis
277:
268:
253:
159:
155:
145:
139:
112:
103:
93:
86:
79:
72:
60:
48:Please help
43:verification
40:
281:stalactites
627:Categories
583:US 5460648
566:References
560:Calthemite
550:Hygroscopy
480:City Hall.
398:admixtures
308:Calthemite
165:of brick.
76:newspapers
345:does not
312:polymorph
202:anhydrite
142:chemistry
638:Concrete
544:See also
402:hydrogen
286:building
169:Examples
163:spalling
643:Masonry
555:Hydrate
454:Germany
366:removed
351:sources
256:masonry
245:Masonry
90:scholar
592:
190:Gypsum
92:
85:
78:
71:
63:
318:(CaCO
260:brick
204:(CaSO
192:(CaSO
97:JSTOR
83:books
616:-108
414:sand
349:any
347:cite
236:.10H
180:NaCl
174:A 5
150:salt
69:news
476:in
472:at
360:by
322:).
314:of
218:.5H
196:.2H
140:In
52:by
629::
574:^
232:CO
208:).
144:,
496:.
456:.
387:)
381:(
376:)
372:(
368:.
354:.
320:3
238:2
234:3
230:2
220:2
216:4
206:4
198:2
194:4
184:K
136:.
119:)
113:(
108:)
104:(
94:·
87:·
80:·
73:·
46:.
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
