Research And Application On Hot In-place Recycling Maintenance Technology Of Asphalt Pavement

Since 1990s, our country has been building massive high-grade highway, which results in a lack of bitumen, aggregate and other road resources; at the same time, the exploitation of these road resources reduces forest vegetation, and leads to soil erosion, air pollution and other environmental problems. According to the discipline that implementing a major and medium repair in every decade, a number of asphalt pavement have entered the maintenance stage. The traditional way of maintenance increases maintenance costs, extends construction period and exerts a serious influence on the existing traffic. Moreover, the asphalt material of pavement renovation is difficult to dispose, which causes the problems of resource waste and environmental pollution. Hot in-place recycling technology of asphalt pavement, considered as a kind of asphalt recycling technology, is the ideal method to solve the problems above. Since the study begins relatively late and this technique has attracted any less attention in our country, it is rarely applied in practical engineering.In this paper, according to the project of hot in-place recycling technology of GK5+000 to GK25+000 section of Dongguan G9411 highway, and researching on the related study of hot in-place recycling technology of asphalt pavement, the contents and results are showed as follows:1. Extension theory based on game theory of comprehensive evaluation model is established to evaluate the pavement performance, on the foundation of investigation and tested data of GK5+000 to GK25+000 section, the model built is applied to waiting-recycling pavement of supported project, which gives a new method for pavement evaluation, and provides reference for time of pavement recycling.2. On the basis of original research, the thermal oxidation aging mechanism of asphalt is studied by four stages of free chain chemical reaction, the photochemical oxidation aging mechanism of asphalt is studied by Norrish Ⅰ and Ⅱ reaction of carbonyl. The recycling mechanism of asphalt is studied based on the theory of component regulation and compatibility; both theories explore the mechanism of recycled asphalt from different views.3. According to the asphalt recycling mechanism and rejuvenating agent mechanism, this paper puts forward solubility parameter method, experience prediction method, performance design method and other methods determining the content of rejuvenating agent; the laboratory tests show that the performance indexes of recycled asphalt and recycled asphalt mixture are closely related to the content of the rejuvenating agent, the relationship of recycled asphalt performance and rejuvenating agent content is based on the method of regression analysis to get the function expression. According to the test, the optimum content of the two kinds of rejuvenating agent is determined, the A-type rejuvenating agent is superior to the B-type of rejuvenating agent.4. The characteristics, applicable conditions and processes of the hot in-place recycling construction technology is studied, and characteristics of several typical hot in-place recycling equipment and construction technology is introduced; according to the supported project, hot in-place recycling construction, construction quality management and acceptance of pavement are studied.