Effect Of Mixing Technology On The Uniformity Of Asphalt Mixture

With the rapid development of highway transportation in China, the quality and service life of asphalt pavement is becoming more and more demanding. Asphalt mixer is the key part of the mechanical construction equipments, its level and performance determine the quality and efficiency of the mixture directly. Currently, there are few studies on mixing technology at home and abroad. This makes the majority of users adjust the parameters of the mixing process according to the experience. There is no experimental data and theoretical basis, so it is not scientific. The quality of the asphalt mixture cannot meet the requirements, which often lead to the early damage of asphalt pavement and reduce its service life.On the basis of the purpose and mechanism of mixing, this paper analyzed the influence of the feeding position, feeding sequence, feeding duration, filling rate and mixing time on the uniformity, efficiency and energy consumption according to the special process of the asphalt mixture. Combining the theoretical analysis, the effect of different parameters on the mixing effect was simulated by using discrete element software EDEM. In order to prove the validity of the analysis, the scheme of the experiment was designed, and the site and laboratory test were carried out on the basis of this.The experimental result shows:(1)The feeding position is the most notable element which effect the uniformity. It mainly affects the initial distribution uniformity of the material, and then affects the mixing quality and efficiency. The transverse central layout is better than the other two forms.(2)The feeding duration mainly affects the rate of materials into the mixer. It is also an important technological parameter which influences the mixing quality and efficiency. With the extension of the powder feeding duration, the uniformity is improved. This is due to the slow rate of the powder feeding, it can realize the fully dispersion and reduce the probability of the asphalt bond, thus improve the mixing quality.(3)In addition to the quality and productivity, the filling rate also has a significantly influence on energy consumption. Under the same condition of mixing time, the increase of the filling rate can improve the productivity of the mixer, but the stirring power and non-uniformity also increase. When the filling rate is higher than 60%, the effect becomes more notable. At this point, the mixing time should be extended to guarantee the quality of the mixture, which actually reduces the productivity of mixer.