The application of new high-speed shearing machines and high-performance mills in the complete set of equipment for modified asphalt

The basic ideas for process and equipment improvement

Both the traditional domestic processes for modified asphalt and emulsified asphalt rely on mills. They first swell and then are processed and produced through repeated multi-sided grinding and long-term incubation. This process has the following drawbacks:

1) Due to the unreasonable process route, the wear of the mill is large and the quality of the modified asphalt product is unstable. Because the SBS after swelling and stirring often forms certain lumps or larger particles, when entering the grinding chamber, due to the limited space and extremely short grinding time, a large internal pressure is generated in the mill, the instantaneous friction force increases, and a huge frictional heat is produced. The temperature of the mixture rises, which is prone to cause some asphalt to age. A small portion has not undergone sufficient grinding and is directly thrown out of the grinding tank, which has a direct impact on the fineness, quality and flow rate of the modified asphalt, and greatly shortens the service life of the mill.

2) Due to the failure to properly handle the SBS blocky issue before grinding, insufficient pre-treatment and the unreasonable structure of the grinding mill, the grinding process always fails to reach a certain fineness, resulting in low production efficiency and unstable product quality of modified asphalt products. The problem needs to be solved by repeated and multiple cycles of grinding and long-term cultivation. This not only significantly increases energy consumption and raises costs, but also leads to unstable product quality and affects the construction speed of highway projects.

2 Solutions

In order to overcome the common problems in the processing of modified asphalt bonding materials, our company has optimized the production process of modified asphalt and made structural improvements to the homogenizer and mill. Through experiments and a period of production, it has been proved that the above problems can be completely solved.

The superiority of new processes and new equipment

The improvement of the process method has greatly enhanced the production efficiency of modified asphalt

We will first make improvements from the process aspect, adopting a method of crushing first and then grinding. The aim is to pre-treat the asphalt and SBS that are initially stirred in the swelling tank before entering the grinding chamber of the mill, thereby reducing the energy consumption of the mill and enhancing its working efficiency.

The reasonable positioning and addition of high-speed shear homogenizers provide a guarantee for improving the quality of modified asphalt products and production efficiency

We independently developed a high-speed shearing homogenizer. Its working process consists of the following steps: First, carry out high-speed and intense stirring to achieve a certain particle size and uniformity; Second, high-speed shearing is carried out. After over a hundred thousand high-speed shears, a certain fineness is achieved. Third, carry out high-speed dispersion to achieve a certain degree of uniformity. After undergoing three processes of high-speed shearing homogenization, asphalt and SBS are in a certain state of fine particle size and uniform dispersion.

3.3 Make significant improvements to the design structure of the dynamic and static grinding discs of the mill

The movement mode of the modified asphalt mixture in the grinding chambers of the dynamic and static grinding discs has been changed from linear movement to curvilinear movement, ensuring the grinding fineness of SBS and improving the quality of the modified asphalt products.

SBS is a highly resilient thermoplastic elastomer. Before entering the grinding chamber of the mill, it must be ground for a sufficient number of times to ensure fineness and quality. For this reason, we have carried out a brand-new design for the dynamic and static grinding discs. When the SBS modifier enters the grinding chamber of the mill, it will jump up and down at high speed under the action of the high-speed rotating centrifugal force, constantly colliding with the dynamic and static grinding discs, generating various complex curved movements. In this way, within the limited space and time of the grinding machine, the probability of grinding is greatly increased, the dispersion and homogenization effect is improved, and thus the fineness, uniformity and stability of grinding are ensured. To ensure fineness and quality with 100% certainty, the grinding is carried out in series through a second mill in the same way. This enhances the grinding efficiency of the mill and the reliability of its quality.

The economic and social benefits of the process and equipment

After the improvement of the process and equipment, the fineness, uniformity and comprehensive indicators of the modified asphalt have been significantly enhanced. This has greatly shortened the swelling and inoculation time and largely reduced the consumption of electricity and heat energy, achieving a certain effect in energy conservation. The usage of modifiers has been reduced, production efficiency has been improved, and to achieve the localization of raw materials, the speed of road construction and maintenance has been accelerated, significantly lowering the cost of road laying.