Research On Road Performance And Microscopic Action Mechanism Of Kaolin Tailing Asphalt Mortar

Kaolin tailing are the solid waste remaining after kaolin mines are processed,which seriously affects the ecological environment.At present,there are few applications of kaolin tailing.In order to widen the application range of kaolin tailing,the kaolin tailing are ground into fine powder and used as fillers in asphalt mixtures.The properties,road performance and microscopic action mechanism of kaolin tailing asphalt mortar and road performance of kaolin tailing asphalt mixture were studied.Scanning electron microscope,laser particle size analyzer test,nitrogen adsorption test,and X-ray diffraction test were performed on kaolin tailing and limestone powder to explore the physical and chemical properties.The results show that the average particle size of kaolin tailing is smaller than that of limestone ore powder,and the specific surface area ofkaolin tailing is larger than that of limestone ore powder.It binds better to asphalt than powder.Asphalt cement was prepared with a powder-to-binder ratio of 0.4,0.6,0.8,1.0,1.2,and 1.4,with kaolin tailing and silane coupling with different dosages(0%,25%,50%,75%,100%).Agent-modified kaolin tailing were used to replace limestone ore powder to make 9 types of asphalt mortars.The prepared asphalt mortars were tested for penetration,softening point,ductility,Brookfield viscosity,BBR,DSR and aggregate adhesion.sex test.The results show that the high temperature performance of kaolin tailing asphalt mortar is slightly worse than that of limestone ore powder asphalt mortar.With the increase of kaolin tailing asphalt mortar content,the low temperature performance first increases and then decreases,and the adhesion performance does not change significantly.Compared with kaolin tailing asphalt mortar,the road performance of silane coupling agent modified kaolin tailing asphalt mortar is improved.Infrared spectroscopy tests were carried out on base asphalt and 1.0 powder-to-binder ratio silane coupling agent-modified kaolin tailing asphalt mortar,100%kaolin tailing asphalt mortar and limestone mineral powder asphalt mortar.The results showed that limestone mineral powder,kaolin tailing The kaolin tailing modified by ore and silane coupling agent have no chemical reaction with bitumen,and their adsorption with bitumen is mainly physical adsorption and selective adsorption.The silane coupling agent chemically reacts with SiO2 in the kaolin tailing,forming a Si-O-Si bond between the kaolin tailing and the asphalt,which improves the adhesion between the kaolin tailing and the asphalt.Different dosages of kaolin tailing asphalt mixture and silane coupling agent modified kaolin asphalt mixture were prepared and the road performance was studied.The results show that the addition of kaolin tailing can reduce the asphalt content of the asphalt mixture.When the content of kaolin tailing is 50%,the comprehensive performance of the asphalt mixture is improved the best.The low temperature performance and water stability performance are significantly improved,and the high temperature Performance is slightly reduced.The road performance of kaolin tailing is improved after being modified by silane coupling agent.Studies have shown that silane coupling agent modified kaolin tailing can be used as fillers in asphalt pavement.