Method for designing old material graded recycled asphalt mixture

Abstract

The invention provides a method for designing an old material graded recycled asphalt mixture, which comprises the following steps of: grading the old asphalt pavement milled and planed old materials,respectively designing the recycled asphalt mixture, adopting a suspended compact structure with the particle size of less than 4.75 mm, fully utilizing old asphalt and fine aggregate in the old materials, and calculating the new asphalt addition amount through a theory by adopting an asphalt film-forming characteristic; designing 4.75-9.5 mm and more than 9.5 mm into a skeleton structure recycled asphalt mixture; adopting the idea that coarse first-grade particles are completely surrounded by fine first-grade particles to construct a coarse aggregate composition mechanism, providing a framework structure recycled asphalt mixture grading design theory, considering the framework structure interference caused by crushing and refining of the coarse aggregates and correcting a recycled asphalt mixture framework structure grading curve . The design theory of the old material graded recycled asphalt mixture is provided. The old material mixing proportion is increased to ensure that the recycled asphalt mixture has the excellent pavement performance and stability, and the method has the important significance for recycling application and popularization of the old asphalt pavement.

Description

technical field [0001] The invention relates to the technical field of road engineering, in particular to a design method for graded and recycled asphalt mixture of old materials. Background technique [0002] Asphalt pavement is the most important type of high-grade highway pavement in my country, with comfortable driving, high safety, fast open traffic and convenient maintenance. Affected by complex environments and loads, asphalt pavement will generally have various diseases and require minor repairs and maintenance in about 5 years, and major and medium repairs will be required in about 10 years. If 30% of the highway roads in the country are maintained every year, 10% The milling and resurfacing of the upper layer of the pavement produced 8.79 million tons of old materials, resulting in an economic loss of about 54 billion yuan, but the actual annual disease damage is far more than this. Pavement regeneration technology is an effective way to regenerate and utilize non...

AI Technical Summary

Problems solved by technology

[0003] The conventional design of recycled asphalt mixture is to classify the old materials according to the grading requirements of the specification, and then carry out the grading design together with the new aggregate. This design method generally uses the old materials as recycled asphalt mixture. Due to the influence of the grading of aggregates in the first grade, the utilization rate of the old materials in each grade is inconsistent, resulting in a large surplus of old materials in some grades, and insufficient old materials in some grades, which seriously affects the use of used materials efficiency

The performance of each old material and its role in the regeneration process are different. The asphalt in the old material is mainly distributed in the fine aggregate. During the regeneration process, the coarse particles play the role of aggregate, and the fine particles replace part of the fine aggregate and asphalt. When mixed, Affected by material properties, the addition of old materials is limited

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