建筑施工混凝土裂縫的預防與處理外文翻譯

1、<p>　　南 京 理 工 大 學 紫 金 學 院</p><p>　　畢業(yè)設計(論文)外文資料翻譯</p><p>　　系： 機械系 </p><p>　　專 業(yè)： 土木工程 </p><p>　　姓 名： 黃亮

2、 </p><p>　　學 號： 090105118 </p><p>　　外文出處：《 CANADIAN JOURNAL OF CIVI ENGINEERING 》</p><p>　　附 件： 1.外文資料翻譯譯文；2.外文原文。 </p><p&

3、gt;　　注：請將該封面與附件裝訂成冊。</p><p>　　附件1：外文資料翻譯譯文</p><p>　　建筑施工混凝土裂縫的預防與處理</p><p>　　混凝土的裂縫問題是一個普遍存在而又難于解決的工程實際問題，本文對混凝土工程中常見的一些裂縫問題進行了探討分析，并針對具體情況提出了一些預防、處理措施。</p><p>　　關鍵詞：混凝

4、土 裂縫 預防 處理</p><p><b>　　前言</b></p><p>　　混凝土是一種由砂石骨料、水泥、水及其他外加材料混合而形成的非均質脆性材料。由于混凝土施工和本身變形、約束等一系列問題，硬化成型的混凝土中存在著眾多的微孔隙、氣穴和微裂縫，正是由于這些初始缺陷的存在才使混凝土呈現(xiàn)出一些非均質的特性。微裂縫通常是一種無害裂縫，對混凝土的承重、防滲及其他一些

5、使用功能不產(chǎn)生危害。但是在混凝土受到荷載、溫差等作用之后，微裂縫就會不斷的擴展和連通，最終形成我們?nèi)庋劭梢姷暮暧^裂縫，也就是混凝土工程中常說的裂縫。</p><p>　　混凝土建筑和構件通常都是帶縫工作的，由于裂縫的存在和發(fā)展通常會使內(nèi)部的鋼筋等材料產(chǎn)生腐蝕，降低鋼筋混凝土材料的承載能力、耐久性及抗?jié)B能力，影響建筑物的外觀、使用壽命，嚴重者將會威脅到人們的生命和財產(chǎn)安全。很多工程的失事都是由于裂縫的不穩(wěn)定發(fā)展所致

6、。近代科學研究和大量的混凝土工程實踐證明，在混凝土工程中裂縫問題是不可避免的，在一定的范圍內(nèi)也是可以接受的，只是要采取有效的措施將其危害程度控制在一定的范圍之內(nèi)。鋼筋混凝土規(guī)范也明確規(guī)定：有些結構在所處的不同條件下，允許存在一定寬度的裂縫。但在施工中應盡量采取有效措施控制裂縫產(chǎn)生，使結構盡可能不出現(xiàn)裂縫或盡量減少裂縫的數(shù)量和寬度，尤其要盡量避免有害裂縫的出現(xiàn)，從而確保工程質量。</p><p>　　混凝土裂縫產(chǎn)生

7、的原因很多，有變形引起的裂縫：如溫度變化、收縮、膨脹、不均勻沉陷等原因引起的裂縫；有外載作用引起的裂縫；有養(yǎng)護環(huán)境不當和化學作用引起的裂縫等等。在實際工程中要區(qū)別對待，根據(jù)實際情況解決問題。</p><p>　　混凝土工程中常見裂縫及預防:</p><p><b>　　1.干縮裂縫及預防</b></p><p>　　干縮裂縫多出現(xiàn)在混凝土養(yǎng)護結

8、束后的一段時間或是混凝土澆筑完畢后的一周左右。水泥漿中水分的蒸發(fā)會產(chǎn)生干縮，且這種收縮是不可逆的。干縮裂縫的產(chǎn)生主要是由于混凝土內(nèi)外水分蒸發(fā)程度不同而導致變形不同的結果：混凝土受外部條件的影響，表面水分損失過快，變形較大，內(nèi)部濕度變化較小變形較小，較大的表面干縮變形受到混凝土內(nèi)部約束，產(chǎn)生較大拉應力而產(chǎn)生裂縫。相對濕度越低，水泥漿體干縮越大，干縮裂縫越易產(chǎn)生。干縮裂縫多為表面性的平行線狀或網(wǎng)狀淺細裂縫，寬度多在0.05-0.2mm之間，

9、大體積混凝土中平面部位多見，較薄的梁板中多沿其短向分布。干縮裂縫通常會影響混凝土的抗?jié)B性，引起鋼筋的銹蝕，影響混凝土的耐久性，在水壓力的作用下會產(chǎn)生水力劈裂影響混凝土的承載力等等?；炷粮煽s主要和混凝土的水灰比、水泥的成分、水泥的用量、集料的性質和用量、外加劑的用量等有關。</p><p>　　主要預防措施：一是選用收縮量較小的水泥，一般采用中低熱水泥和粉煤灰水泥，降低水泥的用量。二是混凝土的干縮受水灰比的影響較

10、大，水灰比越大，干縮越大，因此在混凝土配合比設計中應盡量控制好水灰比的選用，同時摻加合適的減水劑。三是嚴格控制混凝土攪拌和施工中的配合比，混凝土的用水量絕對不能大于配合比設計所給定的用水量。四是加強混凝土的早期養(yǎng)護，并適當延長混凝土的養(yǎng)護時間。冬季施工時要適當延長混凝土保溫覆蓋時間，并涂刷養(yǎng)護劑養(yǎng)護。五是在混凝土結構中設置合適的收縮縫。</p><p>　　2.塑性收縮裂縫及預防</p><p

11、>　　塑性收縮是指混凝土在凝結之前，表面因失水較快而產(chǎn)生的收縮。塑性收縮裂縫一般在干熱或大風天氣出現(xiàn)，裂縫多呈中間寬、兩端細且長短不一，互不連貫狀態(tài)。較短的裂縫一般長20-30cm，較長的裂縫可達2-3m，寬1-5mm.其產(chǎn)生的主要原因為：混凝土在終凝前幾乎沒有強度或強度很小，或者混凝土剛剛終凝而強度很小時，受高溫或較大風力的影響，混凝土表面失水過快，造成毛細管中產(chǎn)生較大的負壓而使混凝土體積急劇收縮，而此時混凝土的強度又無法抵抗其

12、本身收縮，因此產(chǎn)生龜裂。影響混凝土塑性收縮開裂的主要因素有水灰比、混凝土的凝結時間、環(huán)境溫度、風速、相對濕度等等。</p><p>　　主要預防措施：一是選用干縮值較小早期強度較高的硅酸鹽或普通硅酸鹽水泥。二是嚴格控制水灰比，摻加高效減水劑來增加混凝土的坍落度和和易性，減少水泥及水的用量。三是澆筑混凝土之前，將基層和模板澆水均勻濕透。四是及時覆蓋塑料薄膜或者潮濕的草墊、麻片等，保持混凝土終凝前表面濕潤，或者在混凝

13、土表面噴灑養(yǎng)護劑等進行養(yǎng)護。五是在高溫和大風天氣要設置遮陽和擋風設施，及時養(yǎng)護。</p><p><b>　　3.沉陷裂縫及預防</b></p><p>　　沉陷裂縫的產(chǎn)生是由于結構地基土質不勻、松軟或回填土不實或浸水而造成不均勻沉降所致；或者因為模板剛度不足，模板支撐間距過大或支撐底部松動等導致，特別是在冬季，模板支撐在凍土上，凍土化凍后產(chǎn)生不均勻沉降，致使混凝土結

14、構產(chǎn)生裂縫。此類裂縫多為深進或貫穿性裂縫，其走向與沉陷情況有關，一般沿與地面垂直或呈30°-45°角方向發(fā)展，較大的沉陷裂縫，往往有一定的錯位，裂縫寬度往往與沉降量成正比關系。裂縫寬度受溫度變化的影響較小。地基變形穩(wěn)定之后，沉陷裂縫也基本趨于穩(wěn)定。</p><p>　　主要預防措施：一是對松軟土、回填土地基在上部結構施工前應進行必要的夯實和加固。二是保證模板有足夠的強度和剛度，且支撐牢固，并使

15、地基受力均勻。三是防止混凝土澆灌過程中地基被水浸泡。四是模板拆除的時間不能太早，且要注意拆模的先后次序。五是在凍土上搭設模板時要注意采取一定的預防措施。</p><p><b>　　4.溫度裂縫及預防</b></p><p>　　溫度裂縫多發(fā)生在大體積混凝土表面或溫差變化較大地區(qū)的混凝土結構中。混凝土澆筑后，在硬化過程中，水泥水化產(chǎn)生大量的水化熱，（當水泥用量在350

16、-550 kg/m3，每立方米混凝土將釋放出17500-27500kJ的熱量，從而使混凝土內(nèi)部溫度升達70℃左右甚至更高）。由于混凝土的體積較大，大量的水化熱聚積在混凝土內(nèi)部而不易散發(fā)，導致內(nèi)部溫度急劇上升，而混凝土表面散熱較快，這樣就形成內(nèi)外的較大溫差，較大的溫差造成內(nèi)部與外部熱脹冷縮的程度不同，使混凝土表面產(chǎn)生一定的拉應力。當拉應力超過混凝土的抗拉強度極限時，混凝土表面就會產(chǎn)生裂縫，這種裂縫多發(fā)生在混凝土施工中后期。在混凝土的施工中

17、當溫差變化較大，或者是混凝土受到寒潮的襲擊等，會導致混凝土表面溫度急劇下降，而產(chǎn)生收縮，表面收縮的混凝土受內(nèi)部混凝土的約束，將產(chǎn)生很大的拉應力而產(chǎn)生裂縫，這種裂縫通常只在混凝土表面較淺的范圍內(nèi)產(chǎn)生。</p><p>　　溫度裂縫的走向通常無一定規(guī)律，大面積結構裂縫常縱橫交錯；梁板類長度尺寸較大的結構，裂縫多平行于短邊；深入和貫穿性的溫度裂縫一般與短邊方向平行或接近平行，裂縫沿著長邊分段出現(xiàn)，中間較密。裂縫寬度大小

18、不一，受溫度變化影響較為明顯，冬季較寬，夏季較窄。高溫膨脹引起的混凝土溫度裂縫是通常中間粗兩端細，而冷縮裂縫的粗細變化不太明顯。此種裂縫的出現(xiàn)會引起鋼筋的銹蝕，混凝土的碳化，降低混凝土的抗凍融、抗疲勞及抗?jié)B能力等。</p><p>　　主要預防措施：一是盡量選用低熱或中熱水泥，如礦渣水泥、粉煤灰水泥等。二是減少水泥用量，將水泥用量盡量控制在450kg/m3以下。三是降低水灰比，一般混凝土的水灰比控制在0.6以下。

19、四是改善骨料級配，摻加粉煤灰或高效減水劑等來減少水泥用量，降低水化熱。五是改善混凝土的攪拌加工工藝，降低混凝土的澆筑溫度。六是在混凝土中摻加一定量的具有減水、增塑、緩凝等作用的外加劑，改善混凝土拌合物的流動性、保水性，降低水化熱，推遲熱峰的出現(xiàn)時間。七是高溫季節(jié)澆筑時可以采用搭設遮陽板等輔助措施控制混凝土的溫升，降低澆筑混凝土的溫度。八是大體積混凝土的溫度應力與結構尺寸相關，混凝土結構尺寸越大，溫度應力越大，因此要合理安排施工工序，分層

20、、分塊澆筑，以利于散熱，減小約束。九是在大體積混凝土內(nèi)部設置冷卻管道，通冷水或者冷氣冷卻，減小混凝土的內(nèi)外溫差。十是加強混凝土溫度的監(jiān)控，及時采取冷卻、保護措施。十一是預留溫度收縮縫。十二是減小約束，澆筑混凝土前宜在基巖和老混凝土上鋪設5mm左右的砂墊層或使用瀝青等材料涂刷。十三是加強混凝土養(yǎng)護，混凝土澆筑后，及時用濕潤的草簾、麻片等覆蓋，并注意灑水養(yǎng)護，適當延長養(yǎng)護時間，保證</p><p>　　5.化學反應引

21、起的裂縫及預防</p><p>　　堿骨料反應裂縫和鋼筋銹蝕引起的裂縫是鋼筋混凝土結構中最常見的由于化學反應而引起的裂縫。</p><p>　　混凝土拌和后會產(chǎn)生一些堿性離子，這些離子與某些活性骨料產(chǎn)生化學反應并吸收周圍環(huán)境中的水而體積增大，造成混凝土酥松、膨脹開裂。這種裂縫一般出現(xiàn)中混凝土結構使用期間，一旦出現(xiàn)很難補救，因此應在施工中采取有效措施進行預防。主要的預防措施：一是選用堿活性小

22、的砂石骨料。二是選用低堿水泥和低堿或無堿的外加劑。三是選用合適的摻和料抑制堿骨料反應。</p><p>　　由于混凝土澆筑、振搗不良或者是鋼筋保護層較薄，有害物質進入混凝土使鋼筋產(chǎn)生銹蝕，銹蝕的鋼筋體積膨脹，導致混凝土脹裂，此種類型的裂縫多為縱向裂縫，沿鋼筋的位置出現(xiàn)。通常的預防措施有：一是保證鋼筋保護層的厚度。二是混凝土級配要良好。三是混凝土澆注要振搗密實。四是鋼筋表層涂刷防腐涂料。</p>&l

23、t;p>　　出自《加拿大土木工程學報》</p><p>　　附件2：外文原文（復印件）</p><p>　　Building construction concrete crack of</p><p>　　prevention and processing</p><p><b>　　Abstract</b>&l

24、t;/p><p>　　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

25、 concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure. </p><p>　　Keyword:Concrete crack prevention processing</p><p><b>　　Foreword<

26、/b></p><p>　　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

27、the concrete 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

28、of existence just make the concrete present one some not and all the characteristic of qualit</p><p>　　Concrete building and Gou piece usually all take sewer to make of, because of crack of existence and dev

29、elopment 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

30、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 th</p><p>　　Concrete crack cr

31、eation 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 th

32、at 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

33、.</p><p>　　In the concrete engineering the familiar crack and the prevention</p><p>　　1.Stem Suo crack and prevention</p><p>　　Stem the Suo crack much appear after the concrete prot

34、ect 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.St

35、em 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 influen

36、ce, surfac</p><p>　　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 dosa

37、ge 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 c

38、ontrol good water ash ratio of choose to use, the Chan add in the meantime accommodation of r</p><p>　　2.The Su constringency crack and prevention</p><p>　　Su constringency is the concrete is be

39、fore 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, b

40、oth 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:

41、The concrete is eventually</p><p>　　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

42、 the control water ash ratio, the Chan add to efficiently 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,

43、 water basic level and template even to soak through.Four is in time to overlay the perhaps damp grass mat of</p><p>　　3.Sink to sink crack and prevention</p><p>　　The creation which sink to sin

44、k 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

45、 template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress

46、 creation asymmetry to sink to</p><p>　　Main prevention measure:One is rightness loose soft soil, return to fill soil foundation a construction at the upper part structure front should carry on necessity of

47、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 found

48、ation in the process is soak by water.Four is time that template tore down to can't be too early, and want to not</p><p>　　4.Temperature crack and prevention</p><p>　　Temperature crack much

49、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, cem

50、ent water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350-550 kg/m 3, each sign square the rice concrete will release a calories of 17500-27500 kJ and make concrete internal thus t

51、he temperature rise to reach to 70 ℃ </p><p>　　The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave;The size bigger structure of the b

52、eam plank length, the crack run parallel with short side more;Thorough with pierce through sex of temperature crack general and short side direction parallelism or close parallelism, crack along long side cent the segmen

53、t appear, in the center more airtight.Crack width the size be different, be subjected to temperature variety influence m</p><p>　　Main prevention measure:One is as far as possible choose to use low hot or me

54、dium hot water mire, like mineral residue cement, powder ash from stove cement...etc..Two is a decrease cement dosage, cement dosage as far as possible the control is in the 450 kg/m 3 following.Three is to lower water a

55、sh ratio, water ash of the general concrete ratio control below 0.6.Four is improvement the bone anticipate class to go together with, the Chan add powder ash from stove or efficiently reduce water etc. </p><p

56、>　　5.Crack and prevention that the chemical reaction cause</p><p>　　Alkali bone's anticipating the crack that reaction crack and reinforcing bar rust eclipse cause is the most familiar in the reinforc

57、ed concrete structure of because of chemical reaction but cause of crack.</p><p>　　The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creatio

58、n chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open crack.In this kind of crack general emergence concrete structure usage period

59、, once appear very difficult remediable, so should at under construction adopt valid the measure carry on prevention.Main of prevention measure:While being </p><p>　　Because the concrete sprinkle to build, f

60、lap Dao bad perhaps is a reinforcing bar protection layer thinner, the harmful material get into concrete to make reinforcing bar creation rust eclipse, the reinforcing bar physical volume of the rust eclipse inflation,

61、cause concrete bulge crack, the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar appear.Usually of prevent measure from have:One is assurance reinforcing bar protection the thick