外文翻譯--論建筑工程中混凝土裂縫的預(yù)防與處理

1、<p><b>　　中文5153字</b></p><p><b>　　附錄A </b></p><p>　　論建筑工程中混凝土裂縫的預(yù)防與處理</p><p>　　作者：阿西夫·哈米德</p><p>　　摘 要：混凝土裂縫是建筑工程中普遍存在的一種不良現(xiàn)象，它直接影響到混凝土

2、結(jié)構(gòu)的使用功能和耐久性。對(duì)建筑工程中一些常見(jiàn)的混凝土裂縫進(jìn)行了分類(lèi)探討，并對(duì)具體情況提出了一些預(yù)防和處理措施。 關(guān)鍵詞：混凝土；裂縫；預(yù)防；處理 </p><p>　　1 前言  　　 建筑工程施工中，如果混凝土構(gòu)件出現(xiàn)裂縫，就會(huì)影響混凝土構(gòu)件的剛度和建筑物結(jié)構(gòu)的整體抵抗能力，即使裂縫的出現(xiàn)不會(huì)導(dǎo)致混凝土構(gòu)件的破壞或建筑物的倒塌，也會(huì)影響到建筑外觀，當(dāng)裂縫寬度

3、超出一定限度時(shí)，也會(huì)造成鋼筋銹蝕，影響結(jié)構(gòu)構(gòu)件的耐久性能。本文介紹混凝土工程施工中幾種常見(jiàn)裂縫的預(yù)防、控制方法及裂縫的處理措施，對(duì)混凝土工程的施工有一定的參考價(jià)值。  2 常見(jiàn)裂縫分類(lèi)  　　混凝土裂縫產(chǎn)生的原因是多方面的，情況較為復(fù)雜，綜合因素較多。對(duì)于某種裂縫的出現(xiàn)，人們很難給予一個(gè)準(zhǔn)確明晰的原因分析。工程實(shí)踐證明，裂縫形成的原因主要來(lái)自三個(gè)方面：變形、荷載以及不均勻沉降。一般由溫差、收縮

4、、不均勻沉降等引起的變形贊成的裂縫約占80%，荷載等造成的約占20%，當(dāng)然還需要考慮其綜合原因。根據(jù)這些主要影響因素，人們常把混凝土裂縫歸納為收縮裂縫、溫度裂縫、沉降裂縫、徐變裂縫、應(yīng)力裂縫和施工裂縫等幾大類(lèi)。3 常見(jiàn)裂縫分析及預(yù)防 3.1混凝土塑性收縮裂縫及預(yù)防 　　塑性收縮是指混凝土在凝結(jié)前期。表面因失水過(guò)快而產(chǎn)生的收縮。一般在干熱和大風(fēng)天氣裂縫較為常見(jiàn)，形狀多為中間寬、兩端細(xì)、互不連貫且長(zhǎng)</p&g

5、t;<p>　　4 常見(jiàn)裂縫處理方法 </p><p>　　4.1 表面修補(bǔ)法 　　表面修補(bǔ)法是一種簡(jiǎn)單、常見(jiàn)的修補(bǔ)方法，它主要適用于穩(wěn)定和對(duì)結(jié)構(gòu)承載能力沒(méi)有影響的表面裂縫以及深迸裂縫的處理。通常的處理措施是在裂縫的表面涂抹水泥漿、環(huán)氧膠泥或在混凝土表面涂刷油漆、瀝青等防腐材料，在防護(hù)的同時(shí)為了防止混凝土受各種作用的影響繼續(xù)開(kāi)裂，采用在裂縫的表面粘貼玻璃纖維布的方法，當(dāng)混凝土表

6、面裂縫數(shù)量較多，分布面較廣時(shí)，常采用增加一層水泥砂漿或細(xì)石混凝土整體面層的方法處理，同時(shí)整體面層內(nèi)宜配置雙向鋼絲網(wǎng)。 4.2 混凝土置換法 　　混凝土置換法是處理嚴(yán)重?fù)p壞混凝土的一種有效方法，此方法是先將損壞的混凝土剔除干凈、潤(rùn)濕，然后涂刷結(jié)合層，最后再置換入新的高一級(jí)標(biāo)號(hào)混凝土或其他材料。常用的置換材料有：普通混凝土、水泥砂漿、聚合物或改性聚合物混凝土或砂漿。 4.3 結(jié)構(gòu)加固法 　　當(dāng)

7、裂縫影響到混凝土結(jié)構(gòu)的性能時(shí)，就要考慮采取加固法對(duì)混凝土結(jié)構(gòu)進(jìn)行處理。結(jié)構(gòu)加固中常用的主要有以下幾種方法：在構(gòu)件上外包型鋼、粘貼鋼板加固；在構(gòu)件上增設(shè)支撐點(diǎn)加固；在構(gòu)件上施加預(yù)應(yīng)力加固等。 4.4 灌漿、嵌縫封堵法 　　灌漿法主要適用于對(duì)結(jié)構(gòu)整體性有影響或有防滲要求的混凝土</p><p>　　加強(qiáng)混凝土的早期養(yǎng)護(hù)，混凝土澆筑完后，裸露表面應(yīng)及時(shí)用草墊、草袋或塑料薄膜覆蓋，并灑水濕潤(rùn)養(yǎng)護(hù)。

8、在氣溫高、濕度低、風(fēng)速大的天氣應(yīng)及早覆蓋、噴水霧養(yǎng)護(hù)，并適當(dāng)延長(zhǎng)養(yǎng)護(hù)時(shí)間。加強(qiáng)混凝土表面的抹壓，但應(yīng)注意避免過(guò)分抹壓。  　　采用密封保水方法，在混凝土表面噴養(yǎng)護(hù)劑或覆蓋塑料薄膜，使水分不易蒸發(fā)，或采用其他養(yǎng)活空氣流動(dòng)（如設(shè)擋風(fēng)墻、罩）、延緩表面水分蒸發(fā)的辦法。  預(yù)應(yīng)力構(gòu)件應(yīng)及時(shí)張拉，避免長(zhǎng)期堆放。 適當(dāng)選擇配合比，避免水灰比、水泥用量、砂率過(guò)大、嚴(yán)格控制砂、石的含泥量，避免使用粉砂

9、，以提高混凝土抗拉強(qiáng)度。  構(gòu)件長(zhǎng)期露天堆放時(shí)，應(yīng)繼續(xù)適當(dāng)灑水或覆蓋養(yǎng)護(hù)，以便有較長(zhǎng)的保濕養(yǎng)護(hù)時(shí)間，特別是薄壁構(gòu)件，應(yīng)放在陰涼的地方覆蓋堆放。  5.2 溫度裂縫的控制  　　防止混凝土內(nèi)部約束引起的表面溫度裂縫，一般采用控制混凝土表面與外界或內(nèi)部的溫差的方法，使其小于25℃。常用控制措施是：對(duì)加熱養(yǎng)護(hù)的構(gòu)件，應(yīng)采用緩慢升降溫，使升降溫度不大于10℃/h，并注意緩慢揭蓋、脫

10、模，避免表面溫度應(yīng)力過(guò)大；對(duì)大體積結(jié)構(gòu)，當(dāng)混凝土與外界溫差較大時(shí)，應(yīng)采用保溫養(yǎng)護(hù)，適當(dāng)處長(zhǎng)拆模時(shí)間，使溫差控制在25℃以?xún)?nèi)。  　　</p><p>　　5、選擇良好級(jí)配的粗骨料，嚴(yán)格控制其含泥量；加強(qiáng)混凝土振搗，提高混凝土密實(shí)性和抗拉強(qiáng)度；在基礎(chǔ)內(nèi)設(shè)置必要的溫度配筋；在接縫部位，適當(dāng)增大配筋率，設(shè)暗梁，以減輕邊緣效應(yīng)，提高抗拉強(qiáng)度；同時(shí)加強(qiáng)混凝土早期養(yǎng)護(hù)，提高早期抗拉強(qiáng)度和彈性模量。

11、60; 　　6、避免降溫與干縮共同作用導(dǎo)致的應(yīng)力疊加；在混凝土中摻加水泥用量5%-10%的VEA混凝土微膨脹劑，以抵消由于干縮和降溫引起的混凝土收縮，控制混凝土開(kāi)裂。  　　7、采取“雙控計(jì)算”措施，即在澆筑混凝土前按施工條件和擬采取的防裂控制措施，計(jì)算可能產(chǎn)生的最大降溫收縮拉應(yīng)力，當(dāng)發(fā)現(xiàn)超過(guò)計(jì)算齡期的混凝土抗拉強(qiáng)度時(shí)，調(diào)整所采取的措施使應(yīng)力控制在允許范圍內(nèi)；混凝土澆筑后，應(yīng)根據(jù)實(shí)測(cè)溫度和溫度升降曲線(xiàn)，

12、計(jì)算每階段降溫時(shí)混凝土累計(jì)拉應(yīng)力，當(dāng)其大于該齡期的混凝土抗拉極限強(qiáng)度時(shí)，應(yīng)采取保溫養(yǎng)護(hù)措施，使各階段降溫時(shí)混凝土的累計(jì)拉應(yīng)力小于該齡期混凝土允許的抗拉強(qiáng)度，以控制裂縫出現(xiàn)。  　　由于混凝土裂縫產(chǎn)生的原因較為復(fù)雜，應(yīng)根據(jù)具體情況和條件，采取其中一種或數(shù)種措施。  5.3 沉降裂縫的控制  　　沉降裂縫主要在混凝土表面沿水平鋼筋通長(zhǎng)方向出現(xiàn)，分布面比較廣</p>

13、<p><b>　　附錄B外文文獻(xiàn)</b></p><p>　　On the prevention and treatment of cracks in concrete in the construction works</p><p>　　By Asif Hameed </p><p>　　Abstract：Concrete

14、cracks a bad phenomenon is common in construction projects, it directly affects the use of function and durability of concrete structures. Classification of some common concrete cracks in the building works, and the spec

15、ific circumstances of prevention and treatment measures.</p><p>　　Keywords: concrete; cracks; prevention; processing</p><p><b>　　Foreword</b></p><p>　　Building construct

16、ion, concrete structures, cracks, it will affect the stiffness of the concrete structures and the overall resistance of the structure of the building, even if the cracks do not lead to the destruction of concrete structu

17、res or building collapse will affect the exterior of the buildingwhen the crack width exceeds a certain limit, can also cause corrosion, durability of structural elements. This article describes several common cracks in

18、the concrete construction of prevention me</p><p>　　Common cracks Category</p><p>　　Concrete cracks are many reasons, the situation is more complicated, more a combination of factors. For some c

19、racks, it is difficult to give an accurate and clear analysis. Engineering practice shows that the main reasons for crack formation from three aspects: deformation, load, and uneven settlement. Generally by the temperatu

20、re difference, shrinkage, differential settlement cracks caused by the deformation in favor of about 80% load caused about 20%, of course, also need to consider the compr</p><p>　　Common fracture analysis an

21、d prevention</p><p>　　3.1 Plastic shrinkage cracks and prevention</p><p>　　Plastic shrinkage of concrete in the condensation of pre-Surface due to excessive water loss and shrinkage. General mor

22、e common in the dry and hot and windy weather cracks, the shape of the wide in the middle, both ends of the thin, non-coherent and of varying lengths, long cracks up to 2m-3m, width up to 0.5cm, seriously affect the resi

23、stance of concrete permeability and durability.</p><p>　　The main preventive measures: First, make use of the shrinkage value is smaller, higher early strength portland or portland cement. Second, strict con

24、trol of the water-cement ratio, to minimize the amount of water to ensure the concrete construction of the required slump and workability under the premise, if necessary, mixed with superplasticizer. Third, prior to pour

25、ing concrete, grass-roots and templates uniform watering wet. Timely coverage of the grip material film or wet straw mats, hemp fi</p><p>　　Subsidence cracks and prevention</p><p>　　Subsidence c

26、racks in the main is due to the flooding of the structure foundation, soil is uneven or not compacting the backfill caused uneven settlement due. In addition, Concrete hardening process due to the stiffness is insufficie

27、nt or does not firmly support the bottom of the template will cause subsidence cracks.</p><p>　　The main preventive measures: First, the structure of the pre-construction, to ensure the quality of ground tre

28、atment. The original foundation soil must be dense, uniform, carrying capacity and to achieve the design requirements; backfill compaction in layers in strict accordance with the specification, design requirements compac

29、tion factor. The second is to do a good job in the pit or foundation around the protective measures to prevent the foundations were immersed in water. Is to ensure that </p><p>　　3.3 Temperature cracks and P

30、revention</p><p>　　The trend of temperature crack a certain regularity, usually criss-cross, shades. The larger the proportion of long and short sides of the slab structure, cracks parallel to the short side

31、 along the long edge segments appear, in the middle more dense and wide. The width of the cracks by temperature changes, winter, wide, narrow summer. The emergence of such cracks will cause reinforcement corrosion and in

32、ternal concrete carbonation, and seriously affect its function and durability.</p><p>　　The main preventive measures: First, try to use low heat or cooked cement, slag cement, fly ash cement. Second, under t

33、he premise of ensuring the strength of concrete. Improve the aggregate gradation, fly ash or superplasticizer to reduce the amount of cement. Third, to ensure the workability of concrete and meet the construction needs o

34、f the premise, lower water-cement ratio. Is to improve the production process of concrete, reduce the temperature of concrete pouring. Is mixed with a certain am</p><p>　　Chemical reaction caused by cracks a

35、nd Prevention</p><p>　　Alkali aggregate reaction cracks and steel corrosion cracks in two kinds of cracks caused by the chemical reaction is generally divided into the reinforced concrete structure.</p>

36、;<p>　　Construction works is limited to the composition of the concrete, after mixing some alkaline ions, these ions react chemically with some of the reactive aggregate expansion and to absorb the moisture in the

37、 surrounding environment, resulting in shortening of concrete, Splitting. Such cracks generally appear in the concrete structure during the event difficult to remedy, and should therefore take effective measures to preve

38、nt construction. The main preventive measures are: First, the choice of th</p><p>　　Adverse phenomenon due to the reinforced protection of reinforced concrete structures during construction caused by bad thi

39、n, exposed tendons, cellular, pockmarked face, making the hazardous substances and exposed reinforcement through the concrete and internal reinforcement to react to rust, corrosion of reinforced volume expansion, resulti

40、ng in concrete spalling, cracks of this type generally along the reinforced positions. The usual precautionary measures; First, before pouring concrete, stri</p><p>　　Common cracks approach</p><p&

41、gt;　　4.1 Surface repair method</p><p>　　Surface repair method is a simple, common repair method is mainly applied to the processing of stability and no effect on the structure carrying capacity of surface cr

42、acks and deep into the cracks. The usual treatment measures in the cracks in the surface of smear grout, epoxy mortar or concrete surface brushing paint, asphalt and other anti-corrosion materials, continue to crack in o

43、rder to prevent the concrete role in protection while using crack surface paste of glass fiber cloth, when the co</p><p>　　4.2 Concrete replacement method</p><p>　　Concrete replacement method is

44、 an effective way to deal with serious damage to the concrete, this method is removed clean, the first damage to the concrete, wetting, and then brushing the binding layer, and finally replacement into the new high-level

45、 grade concrete or other materials. Replacement material: ordinary concrete, cement mortar, polymer or modified polymer concrete or mortar.</p><p>　　Structural reinforcement</p><p>　　When the cr

46、acks affect the performance of concrete structures, it is necessary to consider taking a reinforced concrete structure processing. Structural reinforcement commonly used mainly in the following ways: outsourcing steel co

47、mponents, paste, steel reinforcement; additional support points on the component reinforcement; prestressed reinforcement in the component.</p><p>　　4.4 Grouting, caulking block method</p><p>　　

48、Grouting method applies to the structural integrity of the influential or the repair of concrete cracks in the impermeable requirements, it is the use of pressure equipment will cementing material pressure concrete crack

49、s cementing material hardened with concrete to form a whole, and thus play blocking the purpose of reinforcement. Commonly used in the cementing material grout, epoxy, methacrylate, polyurethane and other chemical materi

50、als.The caulking is the most commonly used crack block, it u</p><p>　　5. Crack control measures</p><p>　　5.1 Contraction (shrinkage) cracks in the control</p><p>　　Contraction (shri

51、nkage) cracks in the control is to control the humidity changes, the structure of the component has a relatively stable humidity.</p><p>　　To strengthen the early curing of concrete, concrete pouring after t

52、he exposed surface with straw mats, straw bags or plastic mulch, and watering moist conservation. Should try to cover in the high-temperature, low humidity, wind speed, weather, spray mist conservation, and appropriate t

53、o extend the curing time. To strengthen the concrete surface of the wiping pressure, but it should be taken to avoid excessive wiping pressure.</p><p>　　Seal water sprayed on the concrete surface curing agen

54、t or covering of plastic film, so that water can not evaporate, or to use other way to feed air flow (such as set up a wind wall, cover), slow down the evaporation of surface moisture. Prestressed component, to avoid pil

55、ing up long-term tension. Proper mixing ratio, to avoid water-cement ratio, the amount of cement, sand ratio is too large, and strictly control the sand, stone, clay content, avoid the use of silt, in order to improve th

56、e tens</p><p>　　5.2 Temperature control of the cracks</p><p>　　Prevent the surface temperature cracks in the concrete caused by internal constraints, the general control of the concrete surface

57、with the outside world or the internal temperature difference, it is less than 25 ℃. Commonly used control measures are: the components of the heat conservation, the slow heating and cooling, lift a temperature not great

58、er than 10 ° C / h, and pay attention to slow Uncovery, mold release, to avoid the surface temperature of the stress is too large; bulk structure, wh</p><p>　　Prevention of structural concrete temperatu

59、re cracking caused by external constraints, the general technical measures can be taken to the following aspects:</p><p>　　1,A selection of low heat or hot cement (such as slag cement, sulfate resistant ceme

60、nt, fly ash cement) in preparing the concrete; in concrete mixed with fly ash or superplasticizer; use late (90d, 180d) strength to reduce the cement consumption and temperature rise; cooling pipes embedded in the base,

61、pass into the circulation of cold water, and will export the heat of hydration; thickness less gluten, mass concrete, mixed with 20% stone absorbs heat, and can save concrete usage.</p><p>　　2, to avoid the

62、hot weather and pouring concrete at night. Low temperature water mixing concrete, sand and gravel, cold-water mist cooling, or set a simple shading devices to reduce the concrete mixture temperature. By TLC pouring concr

63、ete at the same time, each layer thickness less than 30cm, heat dissipation and heat distribution.</p><p>　　3, good insulation of the concrete, moisture conservation, slow cooling, to give full play to the c

64、haracteristics of creep, reducing thermal stress; summer to avoid exposure, winter insulation cover. Take a long time conservation, and provide for reasonable removal time, and give full play to the concrete stress relax

65、ation effect "; backfill concrete form removal, timely, and to avoid the structural side of the long-term exposure.</p><p>　　4, the large volume basis to take the stratified sub-block placement, a reaso

66、nable set of construction joints, pouring seam in the appropriate location, to speed up the heat; mass concrete pouring on the rock foundation or thick concrete cushion, should be placed on the cushion sliding layer ( po

67、ured mastic asphalt flat, sanding or laying membrane), vertical placed on the buffer layer (attached to polyethylene foam), to remove the embedded solid role in the release of the restraint stress.</p><p>　　

68、5, Choose well-graded coarse aggregate, strict control over its clay content; strengthen concrete vibrators, concrete compacting and tensile strength; set the required temperature reinforcement in the base; the seam area

69、, and increase reinforcement ratio, and concealed beam, in order to reduce edge effects and to improve the tensile strength; early reinforced concrete conservation, improve early tensile strength and elastic modulus.<

70、/p><p>　　6, to avoid cooling and shrinkage joint action of the stress caused by superposition; mixing cement in the concrete amount of 5% -10% of the VEA concrete micro-expanders to counteract the control concr

71、ete cracking due to shrinkage and cooling caused by concrete shrinkage.</p><p>　　7 ,"dual-control computing" measures taken before the pouring of concrete construction conditions and to be taken cr

72、ack prevention control measures, calculate the maximum possible cooling contraction of tensile stress, when found to exceed the calculated age of concrete tensile strength, adjustment measures taken to control the stress

73、 within the allowable range; concrete pouring should be based on the measured temperature and temperature lift curves to calculate each stage of cooling when the co</p><p>　　More complex reasons concrete cra

74、cks, depending on the circumstances and conditions, to take one or several of the measures.</p><p>　　5.3 settlement crack control</p><p>　　Settlement cracks in the concrete surface along the lon

75、g direction of horizontal reinforced through broad distribution of surface, usually in the form removal after the 3d-7d appear, mainly due, if the concrete pouring, the aggregate particles sink, grout float, blocked by s

76、teel or embedded parts or aggregate, cause the concrete separation.In the construction, the general measures taken.</p><p>　　Note the location of material distribution in the concrete construction should be

77、as far as possible less; lower vibration can be reinforced when gently on the upper steel vibration to minimize the upper steel stick with a water slurry; dampened with water before pouring of concrete can be reinforced

78、and the template, reducing the temperature of the reinforcement and templates; summer concrete pouring as much as possible when the temperature is cooler morning or evening; construction reinforced </p><p>　

79、　Pouring concrete should be strict control vibrators, vibrators fully, and should not be too long layered interval.</p><p>　　5.4 Creep crack control</p><p>　　Appropriate to increase the height o

80、f the end cross section, and configured to withstand the horizontal forces reinforced radial reinforcement or bent construct tendons (bent parallel to the direction equal to the principal tensile stress). Bent angle depr

81、ess the prestressing tendons, reduce non-preloading; support node with micro-connection, such as the use of bolted connections, and set aside hole equipped with rubber gaskets, flexible connections to reduce restraint st

82、ress; ERECTION should ha</p><p>　　5.5 construction crack control</p><p>　　Wood template watering wet to prevent the expansion mode to crack the concrete. Flip mold release should be stable to pr

83、event severe shock and vibration, and should be the formation of solid sanding on the ground; the die must be straight prestressed component holes for pouring concrete after the timer (15min) rotating steel pipe , hand-p

84、umped tube pressure concrete surface is not significant imprint is appropriate, smoke pipe should be smooth slow; tire mold release agent should be chosen from </p><p>　　6. Conclusion</p><p>　　T

85、ypes of concrete cracks in large construction projects, and is a common phenomenon, its presence will not only affect the appearance of the building, will also affect the use of the building function and durability, seve

86、re cases will be a threat to people's lives and property safety, according to the different parts, shape and extent of concrete cracks, careful analysis, using a reasonable method for processing, to take effective pr