1、CANADIAN JOURNAL OF CIVIL ENGINEERINGAbstract The crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumst
2、ance put forward some prevention, processing measure. Keyword: Concrete crack prevention processing Foreword Concretes ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the c
3、oncrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic o
4、f quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect
5、, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering. Concrete building and Gou piece usually all take sewer to make of, because of crack of existence and development usually make inner part of reinforcing
6、bar etc. material creation decay, lower reinforced concrete material of loading ability, durable and anti- Shen ability, influence building of external appearance, service life, severity will threat arrive peoples life and property safety.A lot of all of crash of engineerings is because of the unste
7、ady development of the crack with the result that.Modern age science research with a great deal of of the concrete engineering practice certificate, in the concrete engineering crack problem is ineluctable, also acceptable in certainly of the scope just need to adopt valid of measure will it endange
8、r degree control at certain of scope inside.The reinforced concrete norm is also explicit provision:Some structure at place of dissimilarity under the condition allow existence certain the crack of width.But at under construction should as far as possible adopt a valid measure control crack creation
9、, make the structure dont appear crack possibly or as far as possible decrease crack of amount and width, particularly want to as far as possible avoid harmful crack of emergence, insure engineering quality thus.Concrete crack creation of the reason be a lot of and have already transformed to cause
10、of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack;Have outside carry the crack that the function cause;Protected environment not appropriate the crack etc. caused with chemical effect.Want differentiation to treat in the actual engi
11、neering, workout a problem according to the actual circumstance. In the concrete engineering the familiar crack and the prevention.1. Stem Suo crack and prevention Stem the Suo crack much appear after the concrete protect be over of a period of time or concrete sprinkle to build to complete behind o
12、f around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind of constringency is cant negative.Stem Suo crack of the creation be main is because of concrete inside outside humidity evaporate degree dissimilarity but cause to transform dissimilarity of result:The c
13、oncrete is subjected to exterior condition of influence, surface humidity loss lead quick, transform bigger, inner part degree of humidity variety smaller transform smaller, bigger surface stem the Suo transform to be subjected to concrete inner part control, creation more big pull should dint but c
14、reation crack.The relative humidity is more low, cement syrup body stem Suo more big, stem the Suo crack be more easy creation.Stem the Suo crack is much surface parallel lines form or the net shallow thin crack, width many between 0.05-0.2 mm, the flat surface part much see in the big physical volu
15、me concrete and follow it more in thinner beam plank short to distribute.Stem Suo crack usually the anti- Shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack
16、influence concrete of loading dint etc.Concrete stem the Suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of the dosage of the property and dosage, in addition etc. relevant. Main prevention measure:While being to choose to use t
17、he constringency quantity smaller cement, general low hot water mire and powder ash from stove cement in the adoption, lower the dosage of cement.Two is a concrete of stem the Suo be subjected to water ash ratio of influence more big, water ash ratio more big, stem Suo more big, so in the concrete m
18、atch the ratio the design should as far as possible control good water ash ratio of choose to use, the Chan add in the meantime accommodation of reduce water.Three is strict control concrete mix blend with under construction of match ratio, use of concrete water quantity absolute cant big in match r
19、atio design give settle of use water quantity.Four is the earlier period which strengthen concrete to protect, and appropriate extension protect of concrete time.Winter construction want tobeappropriate extension concrete heat preservation to overlay time, and Tu2 Shua protect to protect.Five is a c
20、onstitution the accommodation is in the concrete structure of the constringency sew. 2.The Su constringency crack and prevention Su constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat
21、or strong wind the weather appear, cracks much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creation of main reason i
22、s:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creati
23、on bigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again cant resist its constringency, therefore creation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of con
24、dense time, environment temperature,wind velocity, relative humidity.etc. Main prevention measure:One is choose to use stem the Suo value smaller higher Huo sour salt of the earlier period strength or common the Huo sour brine mire.Two is strict the control water ash ratio, the Chan add to efficient
25、ly reduce water to increment the collapse of concrete fall a degree and with easy, decrease cement and water of dosage.Three is to sprinkle before building concrete, water basic level and template even to soak through.Four is in time to overlay the perhaps damp grass mat of the plastics thin film, h
26、emp slice etc., keep concrete eventually before the Ning surface is moist, perhaps spray to protect etc. to carry on protect in the concrete surface.Five is in the heat and strong wind the weather to want to establish to hide sun and block breeze facilities, protect in time. 3.Sink to sink crack and
27、 prevention The creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the te
28、mplate propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the templateprop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation crack.This kind crack many is deep enter o
29、r pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 s-45 Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direc
30、t proportion relation.Crack width under the influence of temperature variety smaller.The foundation after transform stability sink to sink crack also basic tend in stability. Main prevention measure:One is rightness loose soft soil, return to fill soil foundation a construction at the upper part str
31、ucture front should carry on necessity of Hang solid with reinforce.Two is the strength that assurance template is enough and just degree, and prop up firm, and make the foundation be subjected to dint even.Three is keep concrete from sprinkle infusing the foundation in the process is soak by water.
32、Four is time that template tore down to cant be too early, and want to notice to dismantle a mold order of sequence.Five is at jelly soil top take to establish template to notice to adopt certain of prevention measure. 4.Temperature crack and prevention Temperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal
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