Research On Characteristics Of Segregation In Asphalt Mixtures

A reasonable asphalt mixture gradation and maintain the gradation in the mixture of production, transportation, paving and the process of rolling but not deviating outside the scope of the provisions is the key to ensure the quality of asphalt pavement construction. However, mixture segregation can easily occur during the construction process. This leads to performances of the pavement get bad. Many researches have been carried out on the external causes of segregation home and abroad. But there is very few study about the segregation tendentious from the material composition of the mixture. As a result, it is necessary and urgent to reveal the internal causes of the segregation deeply, and establish the evaluation system.In this paper, widely read in literature at home and abroad on the basis of the current research gaps, the following areas are carried out the study.(1) Describes the different types of isolation resulting from the characteristics and performance of the summary form, and then from the physical aspects of the movement of particle size distribution and design theory point of view of the asphalt mixture segregation mechanism to carry out a preliminary discussion and analysis in order to explain the asphalt Mixture of isolation mechanism, to find better prevention measures, detection and isolation of the summarized and analyzed the pros and cons of various methods and adaptive.(2) By developing a new type of mixture segregation performance test equipment as well as studding the veracity and the adaptability of the ignition method and the centrifugal method, we formed a testing method for the tendentious of mixture segregation. Based on the method it can study the impact of grading and asphalt for the tendentious of asphalt-treated permeable base (ATB) and present a new segregation evaluation index.(3) Asphalt is an important factor in the formation of mixture structure. This paper presents a new method of calculating the thickness of asphalt film by research the thickness of asphalt film. The new method optimizes the calculation of specific surface area and simplifies the calculation of the effective asphalt content. It will contribute to research on segregation performance of the mixture microcosmically. (4) By designing three different degrees of segregated mixtures, using the new method of calculating the thickness of asphalt film to fix the optimum asphalt content, an analysis is made of the influence of different extents of gradation segregation on volume parameter, water stable performance, rut resistance and surface constant so as to establish the permitted range of the segregation degree and the connection of segregation and pavement performances.(5) By study on the tendentious of mixture segregation and the influence of different degrees of gradation segregation we can establish the evaluation system, it involves two aspects: segregation tendentious evaluation and segregation extent evaluation.Through the explorations and researches, it can provide a theoretical basis for asphalt mixture design, construction and segregation testing of the asphalt pavement, to making asphalt mixture has the better performance of the construction and road performance.