Conventional highway pavement are using ordinary asphalt binding material, has been far from meeting high standards and requirements of modern traffic for highway. How to do a good job of high grade pavement asphalt binding material and ensure quality of highway use benefits is a question worth exploring. The slurry seal and micro surfacing technology as a method of preventive maintenance, best quality construction and most economical is being gradually extended.
1、Basic concept and characteristics of slurry seal technology
Emulsified asphalt slurry mixture composition is complex, mainly including cement, fly ash, slag and additives of several components. Slurry mixture with stone or sand as aggregate, sand and stone but choice is not arbitrary, but should reach a certain size, and then add a certain proportion of emulsified asphalt as binder to binding. If situation is special, it can also be added to a certain proportion of powder. After all ingredients are added, mix with water to a certain proportion, and finally form an asphalt mixture. The asphalt mixture formed by these components has mobility, which is more convenient to use when pavement maintenance is carried out. Mixture by slurry spray forming slurry seal car on road. The main technical points of spraying are continuous and uniform. The mixture is formed on surface of asphalt surface treatment layer, which is conducive to development of next process. The main function of this thin layer is to protect original pavement and reduce wear of road surface.
Slurry mixture in a certain proportion of water due to incorporation of easy evaporation in air, water evaporates and becomes dry hardening. Therefore, slurry after molding, not only appearance of fine aggregate and asphalt concrete is very similar, do not affect path of visual perception, and have the same type of concrete and fine wear resistance, skid resistance, waterproof, leveling and other technical performance. Slurry seal technology is widely used in highway pavement maintenance but also because of its advantages of simple construction process, short construction period, low cost, high quality, wide application, strong adaptability, is a kind of asphalt pavement maintenance technology economy and efficiency, it is worthy of application and promotion. In addition, advantages of this technology is also reflected in asphalt and high bond strength of ore, and combination of road firmly, can be fully covered with mineral materials, high strength, good durability.
2、The important role of slurry seal technology in highway maintenance
In the highway maintenance, main material of slurry seal technology is emulsified asphalt, and main function is shown in the following aspects.
First, the slurry seal technology to improve the waterproof performance of the pavement. This function is not separated from mixture of slurry mixture and smaller particle size. These characteristics make it can form a close surface. Smaller size of material to a greater extent to improve the original pavement combination, effectively prevent the rain or snow into pavement. In short, the slurry seal material not only has a smaller particle size and gradation, thus greatly improve the pavement and soil stability, reduce the infiltration coefficient of pavement.
Second, slurry increases the pavement friction, improve pavement antiskid effect. The main points of slurry mixture paving are uniform, so thickness of asphalt mixture is appropriate, and thickness of road surface is not too large. This process is an important factor to ensure pavement quality, in slurry will arise due to excessive bleeding and smooth and other undesirable phenomena leads to decrease of pavement friction and sliding over pavement is not suitable for use. On the contrary, after dilute maintenance technology of slurry seal road mostly with rough surface roughness for the friction coefficient increases properly, maintain in the scope of good, this is the key to ensure the quality of transportation, so as to greatly improve the safety of road operation.
Third, slurry seal well filled in pavement, increase smoothness of road, easy to travel. Because slurry mixture is formed after full combination of moisture, moisture content is more. This ensures its good mobility at the same time, but also on the asphalt pavement minor cracks played a certain role in filling. The cracks will not affect the smoothness of the road surface after filling. The original road often loose and threshing pavement with unequal slurry seal technology to a large extent to improve these problems, to ensure the flatness of the pavement, improving pavement quality, reduce difficulty of driving. Fourth, the slurry seal technology to improve abrasion resistance of pavement, to reduce road damage, prolong service life of road. Dilute the main materials used in emulsified asphalt slurry seal. The advantages of emulsified asphalt are mainly embodied in its high adhesion to acid and alkaline minerals, which greatly enhance the combination of slurry and road surface.
Fifth, appearance of the slurry seal can keep the pavement. The road surface will appear pale, dry wear aging affects the appearance of the phenomenon in the process of long-term use of these phenomena after the slurry seal technology maintenance will be greatly improved.
3、The application of slurry seal technology in highway maintenance
Asphalt pavement is often under the natural conditions of a variety of erosion, prone to cracking and aging phenomenon, which is the quality of the highway often occurs, the need to take timely measures to remedy. Slurry seal technology is mainly the use of emulsified asphalt, so the other way can be better to save resources, reduce environmental pollution compared with asphalt. At the same time, the improvement of the construction condition of the emulsified asphalt is more obvious, can realize the Highway Preventive and periodic maintenance, keep the good condition of the highway for a long time.
Emulsified asphalt is also used in the laying of wear layer. The wear layer should be laid in the original pavement leveling, and then use the slurry seal technology to improve the seal, gravel pavement maintenance quality and antiwear properties from a greater extent.
The adhesion and adhesion of slurry mixture to cement concrete are also strong. The cement concrete ground most often due to excessive pressure cracks and pits or uneven phenomena. At this time often choose the old cement concrete laying slurry mixture, smooth phenomenon can improve the cement pavement due to wear and the joints caused by the improvement due to the bump phenomenon, improve pavement roughness, prolong the service life of cement concrete pavement.
4、Application of micro - surfacing in highway maintenance
Micro surfacing refers to the use of equipment to aggregate, water, additives and fillers and polymer modified asphalt emulsion after a certain percentage of the ratio of mixing surface asphalt content is the use of 63% premises. Performance of asphalt emulsion); thus paving the road to common primary processing technology. The micro surfacing technology can achieve faster traffic, for the protection of the damaged pavement, reduce the extent of the damage; at the same time also belong to one of the pavement maintenance technology high technology, but also one or more layers of cover according to the different use of road damage.
The mixture can be made into a thin layer, usually the thickness of 10mm, suitable for use in the airport road, urban trunk roads and highways and other roads. Because the processing technique is simple, the effect is obvious, and the drainage system of the highway has little influence, so it is widely used in highway pavement maintenance.
The micro surfacing technology has the advantages of simple construction technology, low cost and little pollution, and can effectively reduce influence of construction on road and traffic. To further improve the pavement structure depth and friction coefficient, wait for after forming with sliding abrasion resistance and good anti crack, can effectively repair the pavement, prolong service life of pavement, suitable for large volume of traffic and heavy vehicles road.
In addition, the micro surfacing technology for small porosity and good drainage, can effectively prevent the road surface water infiltration appeared, to protect the base and subgrade cracks; the effective treatment of road surface. Using the micro surfacing technology, the pavement maintenance cost is low, and it also has the advantages of waterproof, non slip, surface function recovery and so on.
Effectively fill up and repair minor damage and track, further improve the smoothness and appearance of the road surface. The use of polymer modifier in the micro surfacing can effectively improve performance of anti rutting. In addition, the thickness of 38mm can be filled with rutting, the effect is ideal; can effectively avoid plastic deformation, in the case of non milling plane can be construction.
The micro surfacing is used as polymer to improve the bond strength; in addition, quality of the aggregate should be used to improve the adhesion strength. The relative use of slurry seal was concerned, effect is more obvious, usually for a busy or heavy traffic road pavement maintenance.
Highway transportation is the important support of national economic development, and it is a complicated systematic project, which is a complicated system engineering, which is an important factor to economic development. In order to ensure the efficiency of road transport, not only should pay attention to the quality of highway construction, but also should pay attention to quality of highway maintenance. Long term maintenance practice of highway, slurry seal and micro surfacing technology has been widely recognized by highway department.