外文翻译---浅谈水泥混凝土路面纵向裂缝的防治.docx

浅谈水泥混凝土路面纵向裂缝的防治1前言水泥混凝土路面的裂缝形式是多种多样的。有表面网裂、横向开裂、纵向开裂等。而对路面使用寿命影响最严重的当属纵向裂缝。这种裂缝一般出现在行车道的中部，一旦发生就是几块或几十块混凝土板连续开裂，而且裂缝贯穿整个板厚；裂缝的宽度也是随着时间的推移而不断的发展，由刚开始时零点几毫米、可发展到几毫米、几厘米，最宽的裂缝可达5cm以上。水泥混凝土路面纵向裂缝是比较严重的一种病害。裂缝在车轮荷载的作用下，随着时间的推移裂缝宽度不断加宽，同时裂缝边缘逐渐剥落破损，直至出现坑槽；由于这种裂缝是贯通板厚的，所以雨水会沿着裂缝下浸基层和路基，造成基础强度下降，最后导致整个路面的破坏。2产生纵向裂缝的原因水泥混凝土路面在运营过程中发生纵向开裂的原因是多方面的但是其主要原因是强度问题。2.1基础纵向裂缝而导致路面开裂路面的基础是路床。路床承受着路面所产生的恒载,同时还承受着由路面传来的行车荷载。基础强度不足，在荷载作用下，必然发生纵向开裂，如果路床发生纵向开裂，就会反射到路面上来。路床的基础可分为两类，一类是零填或挖方段，路床直接座落在天然土层上；另一种是填方路段，路床座落在路堤上。基础纵向开裂的因素比较多，但归纳起来可分以下几类。(1)填方路堤纵向开裂的主要原因是路基的填筑高度从原地面至路床顶面的距离大于80cm这类路基的路基压实度达不到设计或规范的要求。但有时也由于路基分幅填筑而纵向接缝处理不当，或分幅的厚度过大，在两幅之间开成了薄弱面。(2)半填半挖及旧路改建路基半填半挖及旧路改建的路在新建的路在新填的一侧与挖方七旧路基一侧的接茬处，如果处理不好，往往在此处出现纵向裂缝。尤其是挖 方侧是硬土或是岩石，出现纵向裂缝的机率更大。(3)零填及挖方路基这类路基如果出现纵向开裂 主要是基础处理不当或不彻底，基础强度达不到应有的承开能力。在过去和现行的有关规范和标准中，挖方和零填路段基础的处理只对上路床（路槽顶面以下030cm）做了要求，而对下路床（路槽顶面以下3080cm）不做要求，天然状态即可。就普通土而言，天然状态下的土的干密度只有最大干密度的80%左右。其承载力比较低；稳定性聘书很差。所以在路面恒载和汽车动载的作用下，基础首先出现了纵向裂缝。2.2水泥混凝土路面板强度不足水泥混凝土路面板如果不能够有足够抵搞弯拉的能力，那么在汽车荷载的作用下，必然产生纵向开裂等破坏。水泥混凝土路面板强度低主要有两个方面的原因，一是混凝土强度达不到设计值；二是由于施工摊铺的原因而使混凝土板强度达不到设计值。(1)混凝土强度达不到设计要求导致混凝土自身的强度不足有两个方面的因素。一是原材料质量不合格。如水泥掉号，集料强度低或者不均匀，级配不合格，杂质含量超限等。二是在拌和时计量不准改变了混凝土的设计配合比。(2)施工摊铺的原因而使混凝土板强度达不到设计值到目前为止，国内的水泥混凝土路面摊铺工艺不当施工主要采用人工摊铺和机械摊铺两种方法。两种施工方法的本提上的差异是振捣工艺，而影响混凝土板强度的主要原因是摊铺中的振捣工艺。人工摊铺混凝土路面的振捣工艺通常是人工拿振捣插点式振捣；然后由人工拖平板振捣器横向振捣，最后由人工拖振动梁的表面振捣。用振捣棒插点式振捣和平板振捣器振捣，振捣的点位和振捣时间完全由人来控制，在施工的外界环境和操作手人为等因素的影响下，很难做到布点均匀，振捣时间适度。这样，水泥混凝土板就不可能过到均匀密实。众所周知，混凝土的密实程度 直接影响其强度。在行车荷载的反复作用下，混凝土板在不密实处首先产生裂缝。一旦裂缝出现，则在裂缝的两端就会发生应力集中现象，所以，裂缝就很快向两端延伸加长，同时，缝宽也逐渐增加。最终导致混凝土板的破碎。3纵向裂缝的预防措施水泥混凝土路面纵向裂缝 的预防必须从治本开始。前边已经对混凝土路面裂缝产生的主要原因进行了分析，那么预防裂缝的发生就必须针对其采取有效措施。3.1提高基础强度和整体(1)填方路堤在填方路堤施工时，必须按规范和设计要求分层填筑，分层碾压，压实度必须达到设计要求。另外在路基填筑时必须全幅填筑，不应分幅施工，人为地造成纵向工作缝而形成薄弱面。(2)零填及挖方路段在零填及挖方路段的基础处理时，如果路槽范围及路槽以下是普通土或松土时，处理深度不应仅限于上路槽，对于下路槽（路槽顶面以下3080cm范围）也必须处理，其压实度应与上路槽相同。对于特重交通的公路，下处理的深度还应该加深。(3)半填半挖路段半填半挖及旧路加宽路基施工，心须认真处理填方部分与旧路基或原山坡的接茬，在山坡上或旧路基边坡上从填方坡脚向上挖成向内倾斜的台阶，台阶的宽度不应小于1.0m。填方路基的压实度应该相应地提高13个百分点。3.2机械摊铺混凝土路面施工采用水泥混凝土路摊铺机进行施工是提高混凝土板的均匀性、密性、保证其质量的最有利办法之一。就滑模式摊铺机而言，其混凝土振捣程序是先由振动棒振捣，然后再由振动梁振捣。振动棒是在摊铺宽度内等距离均匀布置，其振幅、频率和功率都是可调的，克服了人工摊铺不均匀的缺点。所以摊铺的混凝土板均匀、密实，无薄弱点或薄弱面。3.3强施工管理，保证混凝土质量加强施工管理是确保混凝土质量的重要途径之一。首先控制原材料的质量。各种原材料的各项技术指标都必须满足设计和有关规范要求。不合格的材料不用。其次是混凝土拌和时控制施工配合比，各种材料计量必须准确。最后是控 制新拌混凝土从出机到人模的时间不能超过水泥的初凝时间；同时防止混凝土离析。4裂缝的处理水泥混凝土路面纵向裂缝的处理可采用局部处理和全部处理的办法。在处理之前，必须对裂缝产生的原因进行调查分析，确定是什么原因引起的，然后再确定用什么方法处理。4.1全部处理这种处理方法是将已开裂的混凝土板全部清除，保留横向连接钢筋。 如果基层有破坏进行适当处理，然后重新浇筑与原路面等强度的混凝土板。如果是由于基础开裂 而引起的路面开裂，则应在新浇混凝土板的全宽范围内加设单层或双层钢筋网，钢筋网的规格一般用A10的钢筋制成20*20cm间距即可。这种处理方法适用于各种原因引起的路面开裂。但采用这种方法处理，费用较大。4.2局部处理局部处理是在裂缝两侧各不少于50cm范围内凿一个槽，槽深为板厚的0.50.7倍，槽的两边必须整齐，应采用切缝机切割。槽底要清洗干净，在槽底铺设用A10mm钢筋绑扎的10*10cm的钢筋网，然后浇筑与原路面混凝土强度相等的小石子混凝土，保湿养生28天后开放交通。这种处理方法比较简单经济，但仅适用于路面由于自身强度不足而产生的裂缝。Cement Concrete Pavement On The Prevention Of Vertical Cracks 1 Preface Cement concrete pavement cracks a variety of forms. There is prima facie net crack, horizontal cracks, vertical cracks and so on. Life on the road most affected among the longitudinal cracks. Such cracks are usually the central line of the lane, in the event that a few or dozens of pieces of concrete slab for cracking, and cracks throughout the thickness; the width of cracks is also with the passage of time and continuous development, from the beginning against a few millimeters, can be developed to a few millimeters, a few centimeters, the most wide cracks up to more than 5cm. Vertical cracks in cement concrete pavement is a more serious disease. Cracks in the wheel under load, over time an ever-widening crack width, while gradually off the edge cracks broken until pit there; As a result of this crack is through the thickness, so the rain will be along the crack under the Baptist the grass roots and the embankment, resulting in decreased strength of the foundation, and finally lead to the destruction of the entire road. 2Have vertical cracks Cement concrete pavement occurs during the operation of the vertical cracks are many reasons but the main reason is the question of intensity. 2.1 Based on the longitudinal surface cracks caused by cracking The basis of the road is the road bed. Road, the road bed under the dead load generated, but also came under pressure from street traffic load. The basis of strength in the load, the inevitable occurrence of longitudinal cracking, if the road-bed vertical cracking occurred, it will reflex to the road up. The basis of the road bed can be divided into two categories is zero filling or excavation above the road bed is located directly on the natural soil; the other is the fill section of the road bed is located on the embankment. The basis of the factors of vertical cracks, but there can be summarized in the following categories. (1) Fill Embankment Vertical cracking is mainly due to the high embankment of filling from the ground to the top surface of the road bed is greater than 80cm away from the roadbed subgrade compaction of such degrees can not design or specification requirements. But sometimes also increase as a result of sub-roadbed filling the vertical joints and handled properly, or the thickness increase is too large, in the opening between the two has become the weak side. (2) Half filled and half-dug into the old road embankment Half-filled and the old road a half-dug into the road in the new way to fill one side of the new and the old roadbed excavation side of the seven Department, if handled properly, it often appears in the vertical cracks here. In particular, the side excavation is hard soil or rock, there a greater chance of vertical cracks. (3) Zero-filling and excavation subgrade If this type of subgrade vertical crack is not handled properly or not based on thorough, based on the strength of the bid opening should be less than the capacity. In the past and the existing norms and standards, the excavation and zero-filled sections of the basis for the treatment of only the road-bed (way below the top surface slot 0 30cm) made a request, and on the road under the bed (the way trough the following top 30 80cm) do not require natural state can be. On ordinary soil, the natural state of the dry density of the soil maximum dry density is only about 80%. Its bearing capacity is relatively low; the stability of poor letter of appointment. Therefore, dead load on the road and the role of motor vehicles under the dynamic load, basic first vertical cracks. 2.2 Cement Concrete Pavement strength Cement Concrete Pavement can not be sufficient if the arrival of the ability to engage in bending, then the role of load in the car, the inevitable destruction of produce, such as longitudinal cracking. Cement Concrete Pavement with low intensity, there are two major reasons, one degree less than concrete Taiwan design value; second is due to the reasons for the construction of paving concrete slabs less than the design value of strength. (1)Concrete strength less than the design requirements Lead to less than the strength of the concrete itself has two aspects. First, the quality of raw materials failed. No. away such as cement, aggregates of low strength or uneven grading standard, impurity content, such as transfinite. Second, when mixing the concrete measures are not allowed to change the mix design. (2)The construction of paving concrete slabs less than the design value of strengthSo far, domestic Cement Concrete Pavement Technology improper construction of the main manual and mechanical paver paving methods. Two construction methods of this difference on the vibration process, and impact strength of the concrete slab is mainly due to the vibration process paver. Artificial surface of the vibrated concrete paving process is usually inserted manually using vibrated vibrated point; and then manually drag the horizontal vibration plate vibration device, and finally by the artificial drag of the surface vibration of beam vibration. Interpolation points with rods vibrated vibrated and tablet-style device vibration vibration, vibration and the vibration of the point of time solely by the people to control the external environment during the construction and man-made factors such as operator under the influence, it is difficult to do points to even moderate vibration time. In this way, the cement concrete slab can not be too dense to even. As we all know, the degree of compaction of concrete directly affects its strength. Repeated in the role of traffic load, the concrete slab does not crack the first-compacting Department. Once the cracks appeared in the cracks occur at the two ends of the phenomenon of stress concentration, so the cracks quickly extended to the ends of the extension at the same time, gradually increasing. Eventually lead to broken concrete slabs. 3 Vertical cracks in the preventive measures Cement concrete pavement must be the prevention of vertical cracks started from the root. Front of the concrete pavement has been the main reason for cracks is analyzed, then the prevention of the occurrence of cracks on the need to take effective measures for its. 3.1 The basic strength and the overall (1) Fill Embankment Construction of the embankment fill, it is important to the design requirements in accordance with norms and hierarchical placement, hierarchical RCC, degree of compaction must meet the design requirements. In addition Subgrade must be full-filling should not be at the construction site, the work of artificial joints caused by the vertical plane formed by the weak. (2) Zero-fill and cut sections Zero filling and excavation of the foundation treatment section, if the scope of the road and the road trough trough following is a general soil or loose soil, the deal with the depth of groove should not be limited to the road, the road for the next slot (the way trough the top of the scope of the following 30 80cm ) also have to deal with, and its degree of compaction and the road should be the same slot. For special emphasis on road transport, the depth of processing should also be deepened. (3) A half-dug half-filled sections A half-dug half-filled and the old roadbed construction of the road widening, should be seriously dealt with the heart filled with the old part of the slope of the roadbed or conjunctive phrase, in the slopes of the old roadbed slope or fill slope from digging up the steps into inward tilt , step width of not less than 1.0m. Fill Subgrade compaction degrees should be increased 1 to 3 percentage points. 3.2 Construction of concrete pavement paver machinery Using cement concrete paver road construction is to improve the homogeneity of the concrete slab, Micronesia, and to ensure the quality of one of the best. Sliding mode on the paver, the concrete is vibrated by the vibration program vibration bar, and then vibrated by the vibrating beam. Vibrator in the equidistant uniform width paver layout, and its amplitude, frequency and power are adjustable to overcome the shortcomings of artificial uneven paving. Therefore, the concrete slab paving uniform, dense, no weak points, or weak side. 3.3 Strong construction management to ensure that concrete quality Strengthen the construction management is to ensure that the quality of the concrete one of the important ways. First of all, the quality control of raw materials. A variety of technical indicators of the raw materials must meet the design and the relevant regulatory requirements. Materials do not fail. Followed by the construction of concrete mixing mix control, a variety of materials measurement must be accurate. Finally, there is fresh concrete to control the machine from one mode to the period of not more than the initial setting time of cement; At the same time to prevent concrete segregation. 4 To deal with cracks Vertical cracks in cement concrete pavement may be the deal with all of local processing and handling methods. Before processing, the cracks must be generated to investigate the cause analysis, to determine what causes and then determi