Study On Preparation And Deicing Performance Of Microwave Absorbing Asphalt Mixture

Microwave heating is a new kind of snow and ice removal technology,which has the advantages of environmental protection,fast and high efficiency.The microwave absorption and heating effect of asphalt mixture is poor,which leads to the low efficiency of snow and ice removal by microwave heating.At present,most of the researches on improving the wave-absorbing and heating properties of ordinary asphalt mixture focus on replacing the aggregate in asphalt mixture with iron ore,but the research shows that the structure and properties of asphalt mixture are greatly affected.Therefore,in this paper,carbonyl iron powder,carbon black powder and nickel zinc ferrite powder with strong microwave absorption ability are selected to replace mineral powder in asphalt mixture by equal volume method,so as to improve its wave absorption and heating capacity and realize rapid deicing of road.In this thesis,the physical properties and microstructure characteristics of the absorbing material and mineral powder were analyzed by SEM,XRD,TGA and other microscopic means,and then mixed into SMA-13 asphalt mixture by equal volume method.The high temperature stability and water stability were improved after adding carbon black.After adding carbonyl iron powder,the high temperature stability increases first and then decreases,while the water stability decreases gradually.When Ni-Zn ferrite powder was added,the high temperature stability decreased first and then increased,while the water stability remained unchanged.The low temperature cracking resistance of the three materials decreased slightly.Secondly,through microwave heating test,it is found that after 120 s continuous microwave heating,the temperature of asphalt changes very little,only increased by2.6℃.The mineral powder increased 59.4℃.The three kinds of absorbing materials can reach 89.7℃(nickel zinc ferrite powder),97.9℃(carbon black)and 105.4℃(carbonyl iron powder)respectively after microwave heating at the same time.After120 s microwave heating,the average surface temperature of the fourth grade aggregate is 103.1℃,103.1℃,105.1℃,87.6℃.It can be seen that the temperature difference of the basalt of different particle sizes is small after microwave heating,which indicates that the particle size of the aggregate itself has no obvious effect on the microwave absorption.After heating the absorbing material and aggregate at the same time,it is found that the absorbing material has a significant effect on the heating effect of aggregate in microwave.Then COMSOL multi-physical field numerical simulation software was used to simulate the process of microwave deicing.It was found that the deicing efficiency of wave-absorbing asphalt mixture increased with the increase of the absorption material content.As the ambient temperature decreases,the deicing efficiency also decreases.The deicing efficiency of the same type of absorbing asphalt mixture at-5℃ is about2.6 times of that at-20℃.The increase of ice thickness has little effect on the efficiency of microwave deicing,and the heating rate of characteristic points decreases by0.002～0.004℃/s for every 1mm increase.At last,microwave deicing test was carried out for 30% absorbent asphalt mixture.The analysis results showed that the rule was consistent with the simulation results,but there were some differences in deicing time.