【導讀】土結構的使用功能和耐久性。對建筑工程中一些常見的混凝土裂縫進行了分類探。討，并對具體情況提出了一些預防和處理措施。銹蝕，影響結構構件的耐久性能。本文介紹混凝土工程施工中幾種常見裂縫的預?；炷亮芽p產(chǎn)生的原因是多方面的，情況較為復雜，綜合因素較多。種裂縫的出現(xiàn)，人們很難給予一個準確明晰的原因分析。成的原因主要來自三個方面：變形、荷載以及不均勻沉降。一般由溫差、收縮、還需要考慮其綜合原因。熱和大風天氣裂縫較為常見，形狀多為中間寬、兩端細、互不連貫且長短不一，二是嚴格控制水灰比，在保證混凝土施工所需坍落度和和易性的前提下盡。量減少水的用量，必要時摻入減水劑。四是及時覆蓋握料薄膜或者潮濕的草墊、麻片等，保持混凝土凝結前。牢固也會引起沉陷裂縫。長短邊比例較大的。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。以達到封閉裂縫的目的。在氣溫高、濕度低、風速大的天氣應及早覆蓋、

　　

【正文】 ontrol 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 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 concrete tensile stress accumulated when its greater than the age of the concrete tensile ultimate strength heat conservation measures should be taken so that the accumulated tensile stress of concrete in various stages of cooling is less than allowed by the age of concrete tensile strength, to control the crack appears. More plex reasons concrete cracks, depending on the circumstances and conditions, to take one or several of the measures. settlement crack control Settlement cracks in the concrete surface along the long direction of horizontal reinforced through broad distribution of surface, usually in the form removal after the 3d7d appear, mainly due, if the concrete pouring, the aggregate particles sink, grout float, blocked by steel or embedded parts or aggregate, cause the concrete the construction, the general measures taken. Note the location of material distribution in the concrete construction should be 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 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 the protection layer thickness should be strictly controlled. Pouring concrete should be strict control vibrators, vibrators fully, and should not be too long layered interval. Creep crack control Appropriate to increase the height of 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 depress the prestressing tendons, reduce nonpreloading。 support node with microconnection, such as the use of bolted connections, and set aside hole equipped with rubber gaskets, flexible connections to reduce restraint stress。 ERECTION should have a more long time, the stacking crane girder last fixed as much as possible (Creep 3 months up to 60% the basic stability of four months later, six months creep to be pleted by 70% 80%), the creep deformation in the lifting (or fixed before) most of the concrete has a longer age period, the intensity is also higher。 prestressed concrete members not prematurely put the sheets in order to reduce shrinkage and creep deformation to improve the crack resistance of。 increase the end bearing pad to improve the pressure distribution layer, reducing the stress concentration. construction crack control Wood template watering wet to prevent the expansion mode to crack the concrete. Flip mold release should be stable to prevent severe shock and vibration, and should be the formation of solid sanding on the ground。 the die must be straight prestressed ponent holes for pouring concrete after the timer (15min) rotating steel pipe , handpumped tube pressure concrete surface is not significant imprint is appropriate, smoke pipe should be smooth slow。 tire mold release agent should be chosen from the model before the uniform loose pounds top, and then gently lifting。 ponents stacked according to the branch the affordability of state set the skids, overlapping stacking, the fulcrum should be kept in a straight line, while marked, to avoid the boards, beams and columns Antiput。 transport between the ponents set skids fastened with each other, to prevent shaking large ponent of the collision。 roof trusses, columns, such as lifting, should be required to set the hanging point。 lifting roof trusses, and lateral stiffness ponent, application scaffolding transverse reinforcement, set up and pulling the rope to prevent the lifting process shaking, collision。 concrete in winter construction chlorine mixed with salt as early strength agent, Gaja nitrate should also be doped with rust inhibitor (1% 2% of the cement quality)。 slide template should ensure that the installation of the size and quality of construction Ruoyin some reason stopped sliding time too long, you should release the template and then sliding to prevent crack concrete. 6. Conclusion Types of concrete cracks in large construction projects, and is a mon phenomenon, its presence will not only affect the appearance of the building, will also affect the use of the building function and durability, severe cases will be a threat to people39。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 preventive measures to prevent the emergence and development of cracks in the construction, to ensure that construction material and ponents safe, stable job.