Granular dry modifier for asphalt and preparation method thereof

Abstract

The invention discloses a granular instant dry SBS modifier for an asphalt pavement and a preparation method and application thereof, belonging to the field of road engineering materials. The main component of the granular instant dry SBS modifier is powdery SBS, and a separant, hydrotropic oil, a main cross-linking agent and an auxiliary cross-linking agent can be selectively added. The preparation method comprises the following steps: crushing SBS particles; then adding the separant, the hydrotropic oil, the main cross-linking agent and the auxiliary cross-linking agent into the obtained SBSpowder; and then carrying out cold granulation at a temperature of not higher than 80 DEG C in a flat die or circular die extruder with a cutting length of 10-30 mm so as to obtain the granular dry modifier. The granular dry modifier for asphalt prepared in the invention inherits the advantages of a dry-method process and a wet-method process, and can effectively improve the construction qualityof a pavement while enhance construction flexibility; and in addition, the problems of floating and dust flammability caused by only using micron-sized SBS powder are solved by adopting a prepared cold granulation mode.

Description

technical field [0001] The invention belongs to the technical field of highway engineering materials, and in particular relates to a cold granulation asphalt dry method modifier and a preparation method thereof. Background technique [0002] With the improvement of people's requirements for road construction quality, SBS modified asphalt has become one of the necessary building materials for high-grade road construction because of its excellent high and low temperature performance. According to different methods of use, the use of SBS modified asphalt can be divided into wet process and dry process. The former needs to be prepared in the modified asphalt factory with base asphalt and SBS modifier as raw materials through grinding to obtain finished SBS modified. The asphalt is then transported to the mixing station for mixing with stone materials; the latter directly mixes the dry-process SBS modifier, stone materials, and base asphalt at the mixing station, omitting the pro...

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Problems solved by technology

Although this method can prepare a dry method modifier with a large amount of SBS modifier, there is a serious defect: only the SBS modifier that exists in the state of extremely small particles (particle diameter tens of microns) can affect the performance of asphalt. Modification, even after mixing and granulation in Method 1, the SBS particles with large particle size cannot be crushed into small particles in the short mixing process, and the SBS with large particle size is difficult to exert its effect on the base asphalt added to the mixing plant. With modification effect, compared with the conventional wet method, the road performance is at a lower level

Compared with method 1, method 2 can pre-shear larger SBS particles into small particles, which is helpful to improve the performance of matrix asphalt, but there are still shortcomings: first, due to high-speed shearing, it must be in a liquid state However, SBS exists in a solid state at the processing temperature. In order to facilitate the shearing process, a large proportion of liquid additives such as oleic acid must be added, resulting in a maximum effective SBS ratio of 20% in the dry modifier. Excessively high additives The ratio of the agent not only affects the efficiency, but also has a negative impact on the road performance of the mixture; secondly, with the addition of the stabilizer at high temperature, the SBS crosslinking reaction has already occurred during the preparation of the modifier. At the same time, the three-dimensional network structure formed by cross-linking will be destroyed under the embedding pressure of stone materials, which will not be conducive to the improvement of the performance of matrix asphalt

[0007] It can be seen that there are serious technical defects in the existing two dry method modifier preparation methods. Compared with the wet method, although the construction flexibility is improved, it is difficult to achieve similar road performance, which limits the dry method. Application of law modification technology

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