Building construction concrete crack ofprevention and processingAbstractThe 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 familiarcrack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure.Keyword: Concrete crack prevention processingForewordConcrete'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 withoneself, control etc. a series problem, harden model of inthe concrete existence numerous tiny hole, spirit cave andtiny 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 kindof harmless crack and accept concrete heavy, defend Shen anda little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, differencein temperature etc. function, tiny crack would continuouslyof 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. Concretebuilding and Gou piece usually all take sewer to make of,because of crack of existence and development usually makeinner 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 witha great deal of of the concrete engineering practice certificate, in the concrete engineering crack problem isineluctable, also acceptable in certainly of the scope justneed to adopt valid of measure will it endanger degree control at certain of scope inside.The reinforced concrete norm isalso explicit provision:Some structure at place of dissimilarity under the condition allow existence certainthe crack of width.But at under construction should as faras possible adopt a valid measure control crack creation,make the structure don't appear crack possibly or as far aspossible decrease crack of amount and width, particularlywant 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 temperaturevariety, 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 acco rding to the actual circumstance.In the concrete engineering the familiar crack and the prevention1.Stem Suo crack and preventionStem the Suo crack much appear after the concrete protectbe over of a period of time or concrete sprinkle to build tocomplete behind of around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind ofconstringency is can't negative.Stem Suo crack of thecreation 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 losslead quick, transform bigger, inner part degree of humidityvariety smaller transform smaller, bigger surface stem theSuo transform to be subjected to concrete inner part control, creation more big pull should dint but creation crack.Therelative humidity is more low, cement syrup body stem Suo more big, stem the Suo crack be more easy creation.Stem the Suocrack 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 followit more in thinner beam plank short todistribute.Stem Suocrack 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 wouldcreation the water power split crack influence concrete ofloading dint etc..Concrete stem the Suo be main with waterash of the concrete ratio, the dosage of the composition,cement of cement, gather to anticipate of the dosage of theproperty 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 besubjected to water ash ratio of influence more big, water ash ratio more big, stem Suo more big, so in the concrete matchthe ratio the design should as far as possible control goodwater 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 matchratio design give settle of use water quantity.Four is theearlier period which strengthen concrete to protect, andappropriate 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 accommodation is in theconcrete structure of the constringency sew.2.The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dryheat 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 notcoherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creationof main reason is:The concrete is eventually almost havingno strength or strength before the Ning very small, perhapsconcrete just eventually Ning but strength very hour, besubjected to heat or compare strong wind dint of influence,the concrete surface lose water to lead quick, result in inthe capillary creation bigger negative press but make a concrete physical volume sharply constringency, but at thistime the strength of concrete again can't resist its constringency, therefore creation cracked.The influence concrete Su constringency open the main factor of crack tohave water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc..Main prevention measure:One is choose to use stem the Suovalue smaller higher Huo sour salt of the earlier periodstrength or commonthe Huo sour brine mire.Two is strict the control water ash ratio, the Chan add to efficiently reducewater to increment the collapse of concrete fall a degree andwith easy, decrease cement and water of dosage.Three is tosprinkle 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,hemp slice etc., keep concrete eventually before the Ning surface ismoist, perhaps spray to protect etc. to carry on protect inthe concrete surface.Five is in the heat and strong wind the weather to want to establish to hide sun and block breezefacilities, protect in time.3.Crack and prevention that the chemical reaction causeAlkali bone's anticipating the crack that reaction crack andreinforcing bar rust eclipse cause is the most familiar inthe reinforced concrete structure of because of chemicalreaction but cause of crack.The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creation chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open crack.Inthis kind of crack general emergence concrete structure usage period, once appear very difficult remediable, so should atunder construction adopt valid the measure carry onprevention.Main of prevention measure:While being to choose to anticipate with the alkali activity small freestone bone.Two is the in addition which choose to use low lye mire with low alkali or have no alkali.Three is the Chan whichchoose to use accommodation with anticipate to repress analkali bone to anticipate reaction.Because the concrete sprinkle to build, flap Dao bad perhaps is a reinforcing bar protection layer thinner, theharmful material get into concrete to make reinforcing barcreation rust eclipse, the reinforcing bar physical volumeof the rust eclipse inflation, cause concrete bulge crack,the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar ually of preventmeasure from have:One is assurance reinforcing bar protection the thickness of the layer.Two is a concrete class to go together with to want good.Three is a concrete to sprinkle to note and flap Dao airtight solid.Four is a reinforcing bar surface layer Tu2 Shua antisepsis coating.Crack processingThe emergence of the crack not only would influence structure of whole with just degree, return will cause the rust eclipse of reinforcing bar, acceleration concrete ofcarbonization, lower durable and anti- of concrete tired,anti- Shen ability.Therefore according to the property ofcrack and concrete circumstance we want differentiation totreat, in time processing, with assurance building of safety usage.The repair measure of the concrete crack is main to havethe following some method:Surface repair method, infuse syrup, the Qian sew method, the structure reinforce a method, concrete displacement method, electricity chemistry protection method and imitate to living from heal method.Surface repair the method be a kind of simple, familiar of repair method, it main be applicable to stability and tostructure loading the ability don't have the surface crackof influence and deep enter crack of processing.The processing measure that is usually is a surface in crackdaubery cement syrup, the wreath oxygen gum mire or at concrete surface Tu2 Shua paint, asphalt etc. antisepsismaterial, at protection of in the meantime for keeping concrete from continue under the influence of various function to open crack, usually can adoption the surface incrack glue to stick glass fiber cloth etc. measure.1, infuse syrup, the Qian sew methodInfuse a syrup method main the concrete crack been applicable to have influence or have already defend Shenrequest to the structure whole of repair, it is make use ofpressure equipments gum knot the material press into thecrack of concrete, gum knot the material harden behind andconcrete formation one be whole,thus reinforce of purpose.The in common use gum knot material has the cementthe syrup, epoxy, A JiC Xi sour ester and gather ammonia ester to equalize to learn material.The Qian sew a method is that the crack be a kind of mostin common use method in, it usually is follow the crack digslot, the Qian fill Su in the slot or rigid water materialwith attain closing crack of purpose.The in common use Sumaterial has PVCgum mire, plastics ointment, the D Ji rubber etc.;In commonuse rigid water material is the polymer cement sand syrup.2, the structure reinforce a methodWhen the crack influence arrive concrete structure of function, will consideration adopt to reinforce a method to carry on processing to the concrete structure.The structurereinforce medium in commonuse main have the following a few method:The piece of enlargement concrete structure in everyaspect accumulate, outside the Cape department of the Goupiece pack type steel, adoption prepare should the dint method reinforce, glue to stick steel plate to reinforce,increase to establish fulcrum to reinforce and jet the concrete compensation reinforce.3, concrete displacement methodConcrete displacement method is processing severity damage concrete of a kind of valid method, this method be first will damage of the concrete pick and get rid of, then again displacement go into new of concrete or other material.Thein common use displacement material have:Common concrete orthe cement sand syrup, polymer or change sex polymer concreteor sand syrup.ConclusionThe crack is widespread in the concrete structure existence of a kind of phenomenon, it of emergence not only will lowerthe anti- Shen of building ability, influence building ofusage function, and will cause the rust eclipse of reinforcing bar, the carbonization of concrete, lower thedurable of material, influence building of loading ability,so want to carry on to the concrete crack earnest research, differentiation treat, adoption reasonable of the method carry on processing, and at under construction adopt various valid of prevention measure to prevention crack of emergence and development, assurance building and Gou piece safety,stability work.From《 CANADIAN JOURNAL OF CIVIL ENGINEERING》。