1、Asphalt roadbed disease types and the analysis of the causes In order to effectively deal with diseases of the asphalt pavement, asphalt pavement of the preventive conservation techniques. According to different classification methods, the road surface disease can be divided into different types of

2、diseases caused by the road for many reasons. For road type of disease that may arise in the disease before the appearance of the right time, using reasonable preventive conservation measures are delaying the deterioration rate of pavement performance, extend the life cycle cost savings and an effec

3、tive way. The rapid development of highway construction in China has become the world's second largest State owned highways. With the rapid development of highway construction, road maintenance technology is widespread public concern, the Preventive Maintenance of Asphalt Pavement become a new t

4、opic. Preventive Maintenance refers to the road or the road before the disease occurred in the early disease in a targeted manner to address the conservation of the road in advance to prevent the further expansion of the disease in order to reduce the deterioration of pavement performance rate, the

5、extension of pavement service life. Pavement is divided into 2 categories. One is functional damage to asphalt pavement surface that small micro-cracks, Ma face, peeling,泛油, asphalt aging, diseases of the road a little water and so on, resulting in formation of non-road performance and a decline in

6、anti-slide. So that it no longer has the desired function. The other is structural damage, that is, the surface of asphalt pavement serious cracks, pits, settlement, it is the overall pavement structure or a component of one or more of the damage can be achieved can not be serious when the load bear

7、ing vehicles . This type of damage is not necessarily the same time 2, is generally functional damage occurs first, followed by structural damage. Structural damage to the general need for a thorough renovation, but for functional damage, can be repaired, to restore the conservation of the entire ro

8、ad surface and anti-slide, that is through preventive conservation measures, to improve and enhance the use of good asphalt pavement performance and extending its life to meet the traffic requirements. By the disease occurred at a time can be divided into three stages. The first phase (early deforma

9、tion, damage phase) for the road was opened to traffic after the l 3, the stage of the deformation of asphalt concrete pavement, disease mainly for road vertical and horizontal cracks, surface subsidence caused by subgrade settlement, as well as emerging local potholes. The first stage of deformatio

10、n subgrade stabilized with asphalt concrete pavement of early deformation, disease management, as well as asphalt condensate through the soil surface in the vehicle under repeated loads and constantly re-compacted to achieve the basic stability. Stage of the deformation of the road, the main table f

11、or the disease as a vehicle tire of the constant wear and tear on the road, the track increased, and will appear during the rainy season a small number of holes. The third phase of 8-10 years for road use, the stage of the deformation of asphalt concrete pavement, disease is mainly expressed in the

12、road network cracking until extensive damage, the road gradually lost the use of functions. Deformation of Asphalt Pavement, disease will not only affect the road traffic quality and traffic safety, as well as the life of the road, but also bring about certain social implications. Asphalt pavement c

13、aused by the deformation, diseases are many reasons, there are reasons for the design and construction reasons, the material conditions of the quality of the causes and the reasons for the outside world. Therefore, effective conservation, particularly in preventive conservation to maintain good func

14、tion of the road, and the extension of the service road. 2 Preventive Maintenance Technology Preventive Maintenance is usually used for no damage or only slight signs of defects and diseases of the road. Currently used techniques of preventive conservation, including surface layer, and sealing crack

15、s, such as thin-layer Overlay.2.1 surface layerContinuous manner with the laying of a layer of the entire road surface, the conservation level, closure layer material can be a separate layer of asphalt or other sealing agent may also be composed of asphalt and the aggregate mixture. The purpose of t

16、he surface sealing layer is water-sealing closure, anti-slide, to improve the smoothness, the restoration of surface features. Currently used technology of surface fog layer closure layer, reducing sealing layer, stone sealing layer, such as slurry seal. Application of slurry seal is a wide range of

17、 pre-conservation technologies. Slurry seal technology for the new and old pavement aging, cracking, smooth, loose, pit, such as disease prevention and maintenance can play a role, so that the water surface, anti-slide, formation, rapid increase in wear resistance. Slurry seal molding with rapid sol

18、idification, the early opening of traffic, save spraying and rolling process, a continuum mechanical characteristics, to ensure project quality and easily with low costs. In recent years, with new materials and new technology application, a modified emulsified asphalt slurry seal. Modified emulsifie

19、d asphalt slurry seal is a water emulsion polymer modified asphalt and rolling broken-intensive material, mineral filler, water and additives, composed of the surface treatment layer. Can be characterized by thin-layer paving, solidified quickly, within lh after construction traffic will be open. Mo

20、dified emulsified asphalt as a result of Slurry seal than the ordinary fast curing time, it can be modified emulsified asphalt slurry seal than the traditional thick slurry seal. The main structure for the road finishing, cracking, rutting and other disease treatment, can also be used for sealing an

21、d anti-slide treatment to improve the road surface. 2.2 crack sealingA flexible high-viscosity high viscosity of the crack sealant for sealing cracks in the conservation methods, according to the size of the cracks, conservation methods. 2mm width generally do not deal with the cracks following ,2-6

22、mm can be affixed on the surface of the cover letters to deal with ,6-12 .7 mm expansion joints need to be dealt with, and then injected sealant. 12.7mm of width greater than necessary to repair the cracks of conservation. The disadvantage is that complex operations, the construction time.2.3 Thin-L

23、ayer Overlay Increase in the original road Shop no more than 2.5cm thick layer of hot asphalt mixture. TLC Overlay can be effective in preventing the decline in quality is the continued deterioration of the road surface to improve its flatness, the restoration of the anti-sliding surface resistance,

24、 the correction of the contour surface of the road there is a certain degree of reinforcement, but higher maintenance costs. Thin Overlay in the course of construction the largest dimension of the difficulties is due to thin, easily cooling and should not use vibratory roller, which is not easy to a

25、chieve a higher density. Therefore, the correct mixture design, temperature control, roller and roller selection process is especially important. 3, the timing of preventive conservation For preventive conservation, the key is to choose the right time, according to the type of disease that may arise

26、, to develop appropriate conservation measures. For example, the highway is the main disease of water damage, in preventive conservation, drainage and protection to seize major factor 2 is essential. Drainage system should be an absolute guarantee the normal functioning of the drainage function, Wat

27、er Curb, rapids chutes, Side Ditch, cut-off drain must be intact. If it is found to repair damage as soon as possible and never promised to rain leakage. Retaining wall scuppers must be able to smoothly discharge. Before the rainy season, drainage systems must be done on a comprehensive inspection a

28、nd maintenance. According to statistics, found that there are pit road, not 40 days in the rainy season to carry out remedial work, pit area will be expanded to 5 times, the dry season to expand 1 3 times. Wetter southern areas, the expansion of 8-10 times the pit area, seriously affecting the life

29、of the vehicle and the road surface. Different climatic regions, different subgrade, pavement structure and materials, different traffic conditions, the experience of different construction, as well as the conservation of the history of different road performance of the road have a major impact, in

30、order to ensure the implementation of pre-effect of conservation measures and technological advantages, Conservation Measures in the pre-determined and the timing of the selection process, there is a need to follow the following principles: technology to meet the requirements of the economically mor

31、e savings, the performance characteristics in line with the project. Pavement Preventive Maintenance current time reference of the study, road repair and maintenance of the conservation methods include: damage to the road surface condition index based on the method, moving mass index and damage inde

32、x method, decision tree method, sorting method and the method based on the aging. Some scholars to carry out life-cycle costs based on the Asphalt Pavement Preventive Maintenance time study of the effect by calculating the cost of Than to determine the cost effectiveness of the largest program of pr

33、eventive conservation is the best time to program, and achieved good results. Table 2 gives the surface in different time periods suitable for the use of preventive conservation measures, for reference. Conclusion High-grade asphalt concrete pavement as road surface, in its life cycle, how to conduc

34、t scientific and effective conservation, is a very important issue. Its effect depends on the conservation of materials, technology, equipment 3 factors, which are closely linked, mutual promotion and mutual restraint. Thus the conservation of asphalt pavement technology has a strong feature of the

35、integrated technology. In order to improve and enhance the conservation technologies must be strengthened materials, technology, equipment 3 aspects of technological research and development. Preventive conservation as a recurrent high-grade highways, cyclical maintenance measures, attention should

36、be paid enough attention to realize "the reconstruction of light dependent" to "equal raised to build" the concept of change without delay. Research carried out preventive conservation is to the road for possible diseases, defects in the type and extent of damage, to choose the c

37、orrect and reasonable measures to road maintenance. This will slow down the deterioration rate of pavement performance, extended cycle life and cost-saving is of great significance.瀝青路面產生病害類型以及原因分析為了經濟有效地處理瀝青路面的病害，探討了瀝青路面的預防性養護技術。根據不同的分類方法，路面病害可以分成不同的種類，而造成路面病害的原因是多方面的。針對路面可能出現的病害種類，在病害出現之前的合適時機，采用合

38、理的預防性養護措施是延緩路面使用性能惡化速率、延長使用壽命和節約周期費用的有效方法。 中國公路建設發展迅速，已成為世界第二大高速公路擁有國。隨著公路建設的迅猛發展，公路養護技術得到廣泛關注，瀝青路面的預防性養護成為一個新的課題。預防性養護是指在道路病害出現之前或是路面病害發生初期有針對性地對路面預先養護處理，防止病害的進一步擴展，以減緩路面使用性能的惡化速率，延長路面使用壽命。路面病害分為2類：一類是功能性破壞，即瀝青路面面層出現小微裂縫、麻面、脫皮、泛油、瀝青老化、路面滲水等稍微病害，造成路面的不平整和抗滑性能的下降。使其不再具有預期的功能。另一類是結構性破壞，即瀝青路面面層出現嚴重裂縫、坑

39、槽、沉陷，它是路面結構的整體或其某一個或幾個組成部分的破壞，嚴重時可達到不能支承車輛的荷載。這2類破壞不一定同時發生，一般是先發生功能性破壞，而后出現結構性破壞。對于結構性破壞一般均需進行徹底翻修，但對于功能性破壞，可以通過修整、養護來恢復路面的整性和抗滑性，即通過預防性養護技術措施，改善和提高瀝青路面良好的使用性能和延長其使用壽命，以滿足行車要求。按病害發生的時間可分為3個階段：第一階段（早期變形、破壞階段）為路面建成通車后的l3年，該階段瀝青混凝土路面的變形、病害主要表現為路面縱、橫向開裂，路基沉降引起路面沉陷以及局部出現坑洞。第二階段為隨著路基變形趨于穩定瀝青混凝土路面早期變形、病害通過

40、治理以及瀝青凝土路面在車輛荷載的反復作用下，不斷地再次壓實從而達到基本穩定。該階段路面的變形、病害主要表為由于車輛輪胎對路面的不斷磨損，其車轍增加，且在雨季中會出現少量的坑洞。第三階段為路面使用8-10年后，該階段瀝青混凝土路面的變形、病害主要表現為路面網狀開裂，直到大面積破壞，路面的使用功能逐漸喪失。瀝青路面的變形、病害不但會影響道路的行車質量和行車安全以及道路的使用壽命，還會帶來一定的社會影響。而引起瀝青路面變形、病害的原因是多方面的，有設計原因、施工原因、材料質量原因和外界條件原因。因此，有效的養護，尤其是預防性養護可以保持路面良好的功能性，延長路面的服役期。2預防性養護技術 預防性養護

41、通常用于沒有發生損壞或只有稍微缺陷與病害跡象的路面。目前常用的預防性養護技術包括表面封層、裂縫填封和薄層罩面等。21表面封層 用連續敷設方式在整個路表面上做養護層，封層材料可以是單獨的瀝青或其他封層劑，也可以是瀝青與集料組成的混合料。表面封層的目的是封縫封水、抗滑、改善平整度、恢復表面功能。目前常用的表面封層技術有霧層封層、還原劑封層、石屑封層、稀漿封層等。稀漿封層是目前應用廣泛的預養護技術之一。稀漿封層技術對于新、舊路面的老化、裂縫、光滑、松散、坑槽等病害能起到預防和維修的作用，使路面的防水、抗滑、平整、耐磨性能迅速提高。稀漿封層具有快速凝固成型、早期開放交通、節省噴灑和碾壓工序，一臺機械可連續作業的特點，且輕易保證工程質量，成本較低。近幾年，隨著新材料和新技術的推廣應