Research On Effect Of Snow Melting Agent Erosion On Performance Of Asphalt Concrete And Methods For Its Corrosion Resistance

In winter,heavy snow falls in the northern part of China,causing icy roads,affecting normal traffic operations,and even causing serious traffic accidents.Snow melting agents are widely used in road engineering due to their convenient use,good snow and ice removal effect,and low cost.Research has shown that the erosion of snow melting agents can greatly reduce the high temperature stability,low temperature crack resistance,and water stability of asphalt concrete pavement.Nowadays,research in related fields mainly focuses on the evaluation of the erosion status of snow melting agents on asphalt pavement and the development of environmentally friendly snow melting agents.There is less research on the impact of snow melting agents on pavement erosion and the improvement of asphalt concrete’s resistance to snow melting agent erosion performance.This article studies the impact of snow melting agent erosion on the performance of asphalt and asphalt mixtures,identifies the key factors affecting the effect of snow melting agent on asphalt concrete,and proposes a super hydrophobic surface coating material for existing asphalt pavement.The mix design,anti snow melting agent erosion performance,and anti slip performance of the super hydrophobic surface coating are studied.At the same time,Analyzed the impact of three modification methods for increasing viscosity and toughness of asphalt aggregate interface on the anti snow melting agent corrosion performance of asphalt mixtures for newly constructed asphalt pavement,and evaluated the economic benefits of each asphalt concrete anti snow melting agent corrosion performance improvement technology through the efficacy coefficient method.Firstly,physical properties of asphalt eroded by three snow melting agents,sodium chloride,calcium chloride,and sodium acetate,were tested to characterize the changes in asphalt performance under snow melting agent erosion using changes in softening point,penetration,and ductility indicators;Study the effect of snow melting agent on asphalt concrete through water boiling test,rutting test,small beam bending test,and freeze-thaw splitting test.The results show that the erosion of snow melting agents can cause asphalt to harden,while chloride based snow melting agents can lead to an increase in high-temperature performance and a decrease in low-temperature performance,while acetic acid based snow melting agents can lead to a decrease in both high-temperature and low-temperature performance of asphalt;The erosion of snow melting agents will significantly reduce the adhesion between asphalt and aggregates.The impact of snow melting agents on the adhesion between asphalt and aggregates is mainly caused by invading the asphalt aggregate interface,thereby reducing the adsorption capacity of asphalt and aggregates;Under multiple freeze-thaw cycles,the high-temperature performance,low-temperature performance,and water stability of asphalt mixtures show varying degrees of decline.The decrease in water stability is one of the most important factors affecting the performance of asphalt pavement by snow melting agents.Secondly,the material selection and preparation process of the superhydrophobic coating were determined,and the optimal ratio of each component in the solution was determined through contact angle testing.The resistance to snowmelt erosion,water absorption,permeability coefficient,freeze-thaw splitting,and sliding resistance of the superhydrophobic coating were explored through tests such as resistance to snowmelt erosion,water absorption,permeability coefficient,freeze-thaw splitting,and sliding resistance.The results show that the optimal ratio of superhydrophobic coating is water-based polyurethane: anhydrous ethanol=1:0.5,hydrophobic SiO2/diluted water-based polyurethane: PCTFE/diluted water-based polyurethane=4:4,and FC-4430 accounts for 2%of the total coating mass.At this ratio,the coating has superhydrophobic performance,with a contact angle of 156.60 °;The erosion of the snowmelt solution can lead to a decrease in the contact angle of the coating,but the decrease is limited.The coating can still maintain superhydrophobic properties for a long time under the erosion of the snowmelt solution;After spraying a superhydrophobic coating on the surface,the water absorption rate of the specimen decreases,and the impermeability and water stability are improved.The superhydrophobic coating can reduce the adsorption capacity of the specimen to the solution,while preventing the intrusion of the snowmelt solution into the interior of the asphalt concrete pavement,thereby improving the resistance of the asphalt concrete pavement to the erosion of the snowmelt solution;Spraying superhydrophobic coatings may lead to a decrease in the surface structure depth and swing value of the specimen,but they all meet the requirements for standard use.Thirdly,through rutting tests,small beam bending tests,and freeze-thaw splitting tests,quantify the changes in high-temperature stability,low-temperature crack resistance,and water stability of the modified asphalt mixture under the influence of three snow melting agents: sodium chloride,calcium chloride,and sodium acetate,and analyze and evaluate the asphalt modification The influence of three methods of asphalt aggregate interface adhesion and toughening modification,namely aggregate surface modification and fiber modification,on the resistance of asphalt mixtures to snowmelt erosion.The results show that the water stability of rock asphalt modified asphalt mixture is higher than that of SBS modified asphalt mixture and matrix asphalt mixture under short-term erosion of snow melting agent;The surface modification of aggregates with different materials can enhance the water stability of asphalt mixtures under the influence of snow melting agents.The degree of improvement is as follows: calcium hydroxide>iron oxide>aluminum oxide.Under multiple freeze-thaw cycles,the asphalt mixture modified with calcium hydroxide on the surface of aggregates exhibits better high-temperature stability,low-temperature crack resistance,and water stability compared to the base asphalt mixture under the influence of snow melting agents;Under the influence of snow melting agents,the addition of fibers can improve the water stability of asphalt mixtures after salt freezing cycles,with the degree of improvement being basalt fibers>polypropylene fibers>lignin fibers.Finally,the economic benefits of superhydrophobic coating materials and modification methods for increasing adhesion and toughness at the asphalt aggregate interface were evaluated using the efficacy coefficient method.The results showed that although superhydrophobic coatings increased initial engineering costs,their long-term economic benefits were significant;The material cost of the aggregate surface modification method is relatively low,and under multiple freeze-thaw cycles,its water stability is significantly improved compared to the matrix asphalt mixture,with a higher cost-effectiveness;The economic benefits of three types of fiber asphalt mixtures: polypropylene fiber mixture>basalt fiber mixture>lignin fiber mixture.