Grading optimization method of waste asphalt concrete based on gray system theory

Abstract

The invention discloses a waste asphalt concrete gradating optimization method based on grey system theory, belonging to the material technical field. The method includes performing grading pre-treatment of waste asphalt concrete, building virtual screen size gradation among each grade of waste asphalt concrete direct screening results and the screening results after removal of asphalt, preparing macroporous asphalt concrete under the condition of different virtual screen size gradation blending proportions, performing grey relational analysis and grey correlation degree ordering by adopting porosity deviation changes of macroporous asphalt concrete as the main behavior of the system, and proportional changes of different virtual coefficients in synthesis screening as an effective factor affecting the main behavior, and choosing the virtual screen size gradation with maximum correlation as mixture ratio design basis of actual production of recycled asphalt concrete. The method can accurately control the mixture ratio design of the recycled asphalt concrete, improve recycled asphalt concrete performance, and provide theoretical guidance for application of the waste asphalt concrete in skeleton asphalt mixture.

Description

technical field [0001] The invention belongs to the technical field of materials, and in particular relates to a method for optimizing the gradation of waste asphalt concrete based on gray system theory. Background technique [0002] The scale of my country's road traffic is developing rapidly. As of 2012, the total mileage of road traffic has reached 4.238 million kilometers, and the expressway is 96,200 kilometers, both of which are in the forefront of the world. Among them, 1.81 million kilometers of roads have been in service for more than ten years, and 3.58 million kilometers of roads have been in service for more than five years. These roads have gradually been damaged to varying degrees. Hundreds of millions of tons of waste asphalt concrete (RAP) are produced; in addition, compared with the scale of road construction, my country's crude oil reserves only account for 1.2% of the world's total, and petroleum asphalt resources are scarce and of low quality, leading to a...

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Problems solved by technology

[0004] However, the composition of RAP particles is complex, and it is difficult to control its gradation law in the process of mix ratio design, so it cannot be directly applied to skeleton-type asphalt mixtures such as SMA

The reason why its gradation is difficult to control is that under the high-temperature mixing action, the RAP particles bonded by aged asphalt are dispersed and refined, and after rolling, they exist in the recycled asphalt concrete in the form of unknown particle composition. Among them, at present, regarding the existence state of RAP in recycled asphalt concrete, it is generally believed that the result of direct sieving of RAP particles is its existence state in recycled asphalt concrete, which can be directly treated as black aggregate, that is, "black stone theory", However, in the process of mix ratio design, it was found that the asphalt concrete prepared by the direct screening results of RAP could not stably control its mixture gradation composition. At present, the general scholars believe that RAP is partially melted asphalt and partially "black stone". The United States Imad L.AI-Qadi of the University of Illinois at Urbana-Champaign and Mostafa Elseifi of Louisiana State University confirmed that RAP is in a partially mixed state by using scanning electron microscopy and energy spectrometer. Cheng Zhiqiang and others in China also used the method of specific surface area coefficient to verify the new state of RAP. , the old asphalt partial mixing hypothesis is reasonable [6], but the above research lacks the quantitative regularity conclusion of the existence state of RAP particles, so that the research results cannot directly guide the application of waste asphalt concrete in skeleton asphalt mixture

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