Influence Of Aggregate Dust On Properties Of Asphalt Mixtures And Control Technologies Of The Dust In Asphalt Mixing Station

There are two types of dust pollution in asphalt mixing station.One type is the flying dust during hot mix asphalt production,and the other one is the dust pollution caused by the huge amount of abandoned baghouse dust comes from the dust collection system.Sealing the asphalt mixing station into a plant is an effective way to reduce the dust pollution in the surrounding environment.However,this way increases the dust concentration level in the plant and the deposited dust on the surface of aggregates affects the properties of the asphalt mixture.Based on all these facts,this paper studies how both the limestone dust from hot aggregate bin and the limestone baghouse dust influence the properties of asphalt mixture;the control ratio of limestone dust in hot aggregate bin;whether the limestone baghouse dust can be reused in hot mix asphalt production and how the flying dust distributes in the asphalt mixing plant.Firstly,it analyses the particle size distribution and the plastic index of the aggregate dusts from different hot aggregate bins and varied baghouse dusts.Then,the paper studies the influence of the limestone dust from 1#hot aggregate bin and limestone baghouse dust on the high temperature performance of asphalt mortar by adding different proportion of these dusts in asphalt mortar.In the aspect of the properties of asphalt mixture,Marshall volume index,Marshall stability and flow values,residual stability and TSR are compared by adding six different ratios of limestone dust from 1#hot aggregate bin and limestone baghouse dust to the asphalt mixture.Meanwhile,the control ration of dust in hot aggregate bin and the adding proportion of baghouse dust in asphalt mixture are proposed in the study.Finally,this paper builds three-dimensional geometric model of asphalt mixing station by ICEM and uses ANSYS Fluent to simulate the distribution of dust in asphalt mixing station in different wind speed and wind direction conditions.The dust control effect of the dust cover above cold feed bins is also evaluated in the study.The paper provides pre-theoretical basis and technical assistance for the whole enclosed asphalt plant and dust control in the future.