Building construction concrete crack of
prevention and processing
Abstract
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 circumstance put forward some prevention, processing measure.
Keyword：Concrete crack prevention processing
Foreword
  Concrete's 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 concrete construction transform with oneself， control etc。 a series pr
cracks什么意思中文oblem, 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 of 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, 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 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 people's life and property safety。A lot of all of crash of engineerings is because of the unsteady 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 cr
ack problem is ineluctable， also acceptable in certainly of the scope just need to adopt valid of measure will it endanger 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， make the structure don’t 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 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 engineering, work°out 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 of around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind of constringency is can't 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 concrete 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 creation 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 volume 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 rei
nforcing bar， under the function of the water pressure dint would creation the water power split crack 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 the 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 match 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 can't big in match ratio 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 to be appropriate extension concrete heat preservation to overlay time， and Tu2 Shua protect to protect.Five is a constitution the ac
commodation 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 or strong wind the weather appear, crack’s 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 is：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 creation bigger negative press but make a concrete physical volume sharply constringency， but at this time the strength of concrete again can’t resist its constringency, therefore creation cracked。The influence concrete Su constringency open the main factor of crack to have w
ater ash ratio， concrete of condense time， environment temperature, wind velocity, 。.

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