Review on Research and Application of Colored Asphalt Concrete Pavement
The research and application of colored asphalt concrete pavement can be traced back to 1950s, beginning in Europe and America. This kind of pavement can not only better coordinate with the architectural art around the road, but also beautify the city and induce traffic. It can also reflect the characteristics and style of a country and a city, enhance the image and function of the whole city, and show the elegance and charm of a modern city. This discussion began in the early 1980s in China, but it was rarely used on the road. In recent years, as a new paving technology, it is more and more applied to roads, roads or squares to create an atmosphere of the times.
Second, the color asphalt concrete pavement overview
1, the definition of colored asphalt concrete pavement:
The so-called colored asphalt concrete pavement refers to the colored asphalt concrete pavement with certain strength and road performance. At a specific temperature, the decolored asphalt can be mixed with various colored stones, pigments and additives to prepare various colored asphalt mixtures.
2, color asphalt mixture technical indicators:
(1) The main technical indicators of binder (colored asphalt) shall meet the standard of GB 50092-96 heavy traffic asphalt AH-50 (AH-90 can also be used for non-motor vehicle lanes). That is, penetration (25℃): 40 ~ 60, ductility (15℃)80, softening point (ring and ball method): 45~55.
(2) The Marshall stability of fine colored asphalt mixture is 7.5kN, and the flow value is 20~40. The Marshall stability of fine-grained AC 10 color asphalt mixture is 1 1.9kN, and the flow value is 30.
3. The main performance characteristics of color asphalt concrete pavement:
(1) Good road performance. Under different temperatures and external environment, it has good high-temperature stability, water damage resistance and durability, no deformation, asphalt film peeling and other phenomena, and good adhesion with the base.
(2) The color is bright and lasting, does not fade, and is resistant to high temperature of 77℃ and low temperature of -23℃, and is convenient to maintain.
(3) It has a strong sound absorption function. When the automobile tire rolls at high speed on the highway, it will not produce strong noise due to air compression, and at the same time it can absorb other noises from the outside.
(4) Good elasticity and flexibility, good foot feeling, most suitable for the elderly to walk, and anti-skid in winter. In addition, the color mainly comes from the color of stone itself, which will not cause great harm to the surrounding environment.
Three, color asphalt concrete mixing and pavement construction.
1, mixture mixing should pay attention to the following matters different from ordinary asphalt mixture mixing:
(1) Before mixing, the mixing drum, asphalt pipeline, transport vehicles and construction machinery and equipment of the mixing station shall be cleaned.
(2) In order to make the production target mixture ratio as close as possible to the design mixture ratio, the performance of raw materials should be stable.
(3) The impact on the environment should be considered when adding toner, because the toner accounts for a large proportion and has the functions of coloring, dispersing, adsorbing, stabilizing and thickening in the mixture.
(4) The stirring temperature should be controlled at 160℃~ 170℃, and the stirring time is longer than the ordinary time 10s. After discharging, check whether the granular material and color are uniform in time.
2, mixture paving:
First, check whether the subbase is solid, smooth and clean, and at the same time check whether the paving and compaction machinery is in good working condition;
Then, clean the base and spray 0.3-0.5kgm2 emulsified asphalt. Improve the interfacial adhesion and reduce the infiltration of rainwater into the pavement structure;
Then, in strict accordance with the elevation of loose paving, screed is padded with cushion blocks to ensure that the initial paving thickness meets the requirements; Strictly control the working speed of the paver (speed range: 2.0 ~ 2.5 minutes) to ensure continuous paving;
Finally, full width paving, one-time molding, uninterrupted and timely rolling. Achieve uniform color, uniform and beautiful particles.
3. Compaction molding of the mixture:
(1) Selection of pavement machinery: According to the size of the project and the complexity of the construction site, choose the model, power and quantity of road rollers. Tire roller is not desirable because it will pollute and stick to the road surface.
(2) Pressure combination mode: it is also divided into three stages: initial pressure, secondary pressure and final pressure. The initial pressure temperature should be controlled at 130℃~ 145℃, and the final pressure temperature should not be lower than 70℃. The principle of following closely, slowly pressing, high frequency and low amplitude should be followed when rolling.
Firstly, according to the paving results of the test section, the rolling combination mode is determined;
Then, after the pavement is statically pressed 1 pass with a heavy roller, it is lightly vibrated 1 pass, that is, the initial compaction is completed;
Then, the light roller completes the main work of recompression, and determines the rolling times according to the site conditions until compaction;
Finally, when the pavement temperature drops to 80℃, start the final pressure, and use the heavy-duty road roller for static pressure 1-2 times to completely eliminate the wheel tracks.
(3) Details that should be paid attention to during compaction:
(1) The steel wheel should be properly lubricated to avoid material sticking on the roller of the steel wheel. It is suggested to add a proper amount of washing powder (0. 15kgm3) to the water tank of the drum.
(2) Combined compaction by light and heavy rollers. In order to avoid the damage of heavy roller steel wheels to kerbs, the area near kerbs of 15CM is rolled by light roller.
(3) Ensure that the rolling equipment is clean before rolling, so as to prevent the surface of colored asphalt from being polluted.
Advantages, Application and Development of Color Asphalt Concrete Pavement Technology
1, color asphalt concrete pavement technology has two advantages:
(1) has the functions of beautifying the city, improving the road environment and displaying the city features, and is specifically applied to urban streets, squares, scenic spots, parks and tourist attractions.
(2) It has the function of inducing traffic flow and making traffic management intuitive, and is specifically applied to distinguish road sections and lanes with different functions, so as to improve the driver's identification effect, increase road capacity and traffic safety.
The most typical applications of colored asphalt concrete pavement in foreign countries are: Japan Kyushu 199 national road (street section) paved with iron red pavement; On the northeast road of Paris, France, there is a road about 30km long, and the road surface is blue; In Amsterdam, The Hague, Rotterdam and other cities in the Netherlands, there are 1.5~2.0m iron-red asphalt pavement bicycle lanes on the sidewalks. The boulevard in front of Buckingham Palace in London, England is paved with iron red roads and so on.
The most typical applications of colored asphalt concrete pavement in China are: non-motor vehicle lanes about 4km on both sides of Xiamen Avenue and tourist attractions around the island; Beijing Chang 'an Avenue Extension Line, Lu Xindacheng Color Basketball Court, Shijingshan Playground; Shenyang Botanical Garden Color Tour Road, Botanical Garden Color Tour Road (Phase II), Luda Color Roof, Huaxing Middle School Color Playground and Shenyang Beijing Street and Beiling Street Color Landscape Road; Shanghai Zhaojiabang Road and Taiyuan Road are slow lanes, Chengdu Tudor Street is 100 meters, Wuhan Jiangtan will build an 8-meter-wide expressway, Yantai Binhai Middle Road Colorful Guanjing Road, Guangzhou Huangpu Avenue and Chebei Road intersection to Guangyuan East Expressway, colorful plaza of Liaoning Building, Nanjing Shengzhou Road sidewalk, etc.
At present, China's colored asphalt concrete pavement has been successfully laid in more than 20 cities such as Xiamen, Guangzhou, Ningbo, Guilin, Yantai and Beijing, and the effect is quite good, which is well received by the world.
2. Development of color concrete pavement technology: At present, foreign countries focus on the research of color asphalt and its concrete pavement technology product series and varieties, which are specifically manifested in the following aspects:
The production mode of (1) binder (colored asphalt) has developed from the traditional decompression and degradation to the preparation of polymer light-colored binder (colored asphalt) with the same performance as asphalt by using modern industrial petrochemical products, and red, yellow, blue, green and camel (natural color) series colored asphalt has been developed, with better color and performance and longer service life.
(2) The production and construction technology of colored asphalt concrete has been continuously improved and great achievements have been made. Many kinds of colored asphalt concrete pavements, such as red, yellow, blue and green 10, have been laid and developed successively, forming a set of application technologies of colored asphalt concrete pavements.
(3) Colored asphalt concrete materials are mixed with materials that can emit light at night, such as glass beads. The lighting effect is better, making the road more eye-catching at night. In view of the complex lines and numerous vehicles in China's highway network, it has high practical value.
(4) Another technology is color slow-cracking and quick-setting emulsified asphalt slurry seal coat. It is a kind of color slurry seal pavement which combines color asphalt and slurry seal technology. Because of the thin layer covering, there is no need to pretreat the original pavement, such as milling and planing, which is convenient for construction and reduces the cost of colored asphalt pavement. This technology fills the gap in China, is suitable for urban construction and has high development value.
In a word, colored asphalt concrete pavement has great advantages in beautifying the environment, adding color to the urban landscape, guiding traffic and reducing traffic accidents, and it is not inferior to ordinary asphalt highway in terms of highway performance, although it is inferior to ordinary asphalt highway in terms of materials and cost. However, it can be seen that after several years of research, the technical performance of colored asphalt concrete pavement in China has basically kept pace with the international advanced level. Therefore, it is believed that with the further development of color asphalt concrete pavement technology research and the further formation of construction method system, the disadvantages in this respect will gradually disappear. China is marching towards a world power. In the future, more and more colorful asphalt concrete pavement technologies will be applied to urban road construction. According to the current development trend of highway construction in China, some experts have analyzed that colored asphalt concrete pavement is another hot spot in highway construction.