Study On The Durability Of Asphalt Concrete Road Under The Snow Melting Agent

It is cold in northern regions,therefore snow can cover lots of roads easily.Sprinkling snow-melting agent is one of the most common methods to ensure the safety of driving vehicles in snowy weather.But after snow melts,surface of asphalt concrete road often covers with a layer of black "Snow water" and it will also bring a certain degree of uneven and tiny cracks.In order to find out whether the snow-melting agent can affect the durability of asphalt concrete on road,this paper puts forward some reliable references for this kind of engineering problems and gives some optimization solutions through theoretical analysis and experimental verification.From the three aspects of matrix asphalt,asphalt mixture and asphalt concrete pavement,the research on durability of asphalt concrete under snow-melting agent is carried out.Firstly,the experiment prepared some thin asphalt specimens and took cycling experiment which is similar to the condition of the project.The indexes of softening point,ductility,needle penetration and adhesion are used to estimate the macro indicators such as high temperature stability,low temperature resistance to deformation,crack resistance and adhesion grade.Then I analyzed the micro mechanism by infrared spectroscopy.Secondly,by doing simulation test of three couples through a snowmelt agent-roller fatigue-freezing and thawing cycle,I combined with image J software to quantitative analysis the surface damage meso index such as surface void ratio,aggregate change and asphalt binder content of asphalt mixture.Then the macro damage amount was analyzed,such as the size of the surface pit,the loss rate of the mass.The overall performance was evaluated with Marshall Stability,and I discussed the failure mechanism with the correlation test of bitumen binder under the snow-melting agent.Finally,the durability of asphalt mixture is estimated by the theory of cumulative fatigue damage,and the life of asphalt concrete pavement under snow-melting agent is calculated and evaluated by the ideal comparison and hypothesis.The test results show that under snow-melting agent the high temperature stability of asphalt binder is improved,and the resistance to deformation and crack resistance at low temperature decreased and the adhesion grade decreased.Snow-melting agent and asphalt binder reacted chemically.The soft components of saturated hydrocarbons and aromatic hydrocarbons are converted into hard component and asphaltene.In a word,the asphalt binder is "hardened" after the soaking of the snow-melting agent.The test results show that because of the corrosive effect of snow-melting agent and the cycle of freeze-thaw,the asphalt adhesion properties was reduced.The wheel rolling causes excessive pore water,pavement local weakness and damage pressure lead to structural integrity reduced.Meanwhile the impact load is increased.In short,the durability of asphalt concrete road will be greatly reduced after spraying snow-melting agent.In this paper,a more comprehensive study is carried out through theoretical analysis and experimental demonstration,and a reliable reference for such engineering problems is put forward and the relevant optimization solutions are put forward in order to protect the road infrastructure and reduce the cost of the project.