Effect Of Snow Melting Agent On Performance Of Asphalt And Its Mixture

Snowfall in winter has caused a lot of snow and ice disasters,which not only hindered travel,but also caused many traffic accidents.Then,the snow melting agent is widely used to melt snow and reduce freezing point,and improve the safety performance of roads in winter.However,studies have shown that the snow melting agent has a negative impact on the performance of asphalt pavement.Therefore,this article mainly studies the effect of snow melting agent on the road performance of asphalt and asphalt mixture and the micro-mechanism of snow melting agent on asphalt damage.In this paper,three commonly used snow melting agents,sodium chloride（NaCl）,calcium chloride（CaCl₂）,and potassium acetate（CH₃COOK）,were added directly into70#Ssangyong matrix at four levels of 1%,2%,3%,and 4%respectively.Asphalt and 4%SBS（Styrene-butadiene-styrene）modified asphalt are used for experimental research.When studying asphalt mixtures,snow melting agents are used instead of 50%by volume of ore powder to form mixture test samples.First,the softening point,penetration（25℃）,ductility（5℃）,Brinell viscosity of 135℃,dynamic shear rheology,atomic force microscopy,and Fourier infrared spectroscopy were performed on matrix asphalt and SBS modified asphalt.Then,the base asphalt and the SBS modified asphalt mixed with the snow melting agent were aged in a rotary film oven for 85 min,and then the aged asphalt was subjected to dynamic shear rheology,atomic force microscopy,and Fourier infrared spectroscopy.In addition,the water stability,high temperature rut test and low temperature trabecular bending test were performed on the asphalt mixture to study the effect of the snow melting agent on the performance of the modified asphalt mixture.The results show:（1）Three types of snow melting agents reduce the ductility and penetration of matrix asphalt,increase the softening point and viscosity.The snow melting agent reduces the softening point,ductility,and viscosity of SBS modified asphalt,increases the penetration.The effect is most obvious when the amount of snow melting agent is 4%.（2）The phase angle of matrix asphalt is reduced by the snow melting agent,and the complex shear modulus and rut resistance factor are increased,while the SBS modified asphalt is the opposite.The effect is greatest when the amount of snow melting agent is 2%-3%.（3）There is no chemical change in the snow melting agent in the matrix asphalt and SBS modified asphalt,and as the amount of the snow melting agent increases,the carbonyl index decreases and the sulfoxide index increases.（4）NaCl increases the roughness,adhesion,and DMT modulus of matrix asphalt and SBS modified asphalt,and the increase is more obvious after aging.In addition,the change is most obvious when the dosage is 2%.At the same time,it also increases the bee-like structure area of matrix asphalt and SBS modified asphalt.（5）Snow melting agent reduces the water stability,high temperature rut resistance and low temperature crack resistance of AC-13 asphalt mixture,but still meet the requirements of the specification.（6）CH₃COOK has the least impact on asphalt and mixtures,but CH₃COOK snow melting agents are too expensive to use in large quantities,so CaCl₂ is recommended as a snow melting agent,which has less impact on asphalt and asphalt mixture with high cost performance.