The Study On Drying Process Of Emulsified Asphalt And Emulsified Asphalt Paste

Emulsified asphalt,as a road building material,is widely used in pavement construction,preventive maintenance and regeneration projects due to its excellent performance of environmental protection and construction safety.However,due to its slow strength formation and insufficient mechanical properties,the further development of emulsified asphalt has been restricted by the main reasons.The drying process of emulsified asphalt largely determines the strength formation and mechanical properties of emulsified asphalt and emulsified asphalt mixture in the later stage.However,due to the lack of appropriate analysis methods and evaluation indexes in the drying process of emulsified asphalt,there are few studies in relevant aspects.Starting from the drying of emulsified asphalt,this paper studies the influence mechanism of the drying film forming process of emulsified asphalt and emulsified asphalt under the action of mineral materials.The main work contents and research results of this paper are as follows:(1)Through the theoretical analysis of emulsion film formation and the study of emulsified asphalt solid content,thickness and temperature drying process,the drying process of emulsified asphalt is mainly divided into three stages,which are the filling stage of latex particles,the deformation stage of latex particles and the diffusion and fusion stage of latex particles.The evaluation index of the drying process based on the maximum bituminous particle accumulation volume ratio φm was put forward.(2)By changing the temperature,emulsifier,storage stabilizer and wetting agent of substrate asphalt during the preparation of emulsified asphalt,the drying state of emulsified asphalt under different conditions was studied.The results showed that the temperature of substrate asphalt at 120 ℃-160 ℃ had little effect on the drying process of emulsified asphalt.Relatively speaking,among the three emulsifiers,the KZW emulsifier has a short drying time and good drying film forming effect.It is found that the storage of stabilizer and wetting agent is unfavorable to the drying effect of emulsified asphalt.By means of microscopic observation,it is found that the existence of large particles will lead to the increase of pores in the film formation of emulsified asphalt,thus affecting the film formation effect.(3)The factors influencing the drying process of emulsified asphalt mortar were studied,including the ratio of filler in the mortar and the types of emulsified asphalt mortar,the drying model of emulsified asphalt mortar was established,the evaluation indexes of the drying process of emulsified asphalt mortar were put forward,and the transfer of drying parameters of emulsified asphalt mortar between emulsion and mortar was analyzed.The results showed that the drying process was slowed down and the film forming effect was worse when cement was added,but the proportion of cement had no effect on the drying process.Under emulsified asphalt with different emulsifiers,the drying difference of slurry is mainly reflected in the second stage,and the drying effect is the best with KZW emulsifier.Adding silica can promote the drying and film formation of emulsified asphalt mortar.Under the conditions of 25℃,wind speed of 0.4 m/s and thickness of 3mm,the maximum volume ratio of bulk transfer from emulsion to slurry decreased obviously.