Preparation And Performance Study Of Thin Layer Of Low Freezing Point Anticoagulant Ice Asphalt Mixture

The phenomenon of snow and ice condensation seriously affects the driving safety,traffic capacity and operational efficiency of roads,and how to solve the problem of road ice condensation is the focus of domestic and foreign scholars.The thin layer of low freezing point anti-condensed ice asphalt uses low freezing point anti-condensation ice material to partially or completely replace fine aggregate or mineral powder filler,and effectively acts in anti-condensation ice material under the influence of driving load and capillary pressure to analyze it to the road surface,by reducing the freezing point of road snow water,prolonging the freezing time,reducing the adhesion between ice condensation and pavement paving to solve the problem of snow and ice condensation on the road.Firstly,through the compounding of calcium and magnesium acetate salt(CMA),the anticoagulation effect of calcium acetate and magnesium acetate ratio on CMA was studied by combining calcium and magnesium acetate salt,and the ratio with the lowest freezing point of CMA solution was used as the ratio of the active ingredient of anticoagulation ice material.The carrier components and hydrophobic functional components were selected,and the low freezing point anti-condensation ice material was prepared by surface adsorption method,and the optimal ratio of each component of the anti-condensation ice material was studied by taking conductivity as the index.The test results show that when the mass ratio of calcium acetate to magnesium acetate is 4:1,CMA can minimize the freezing point of water.When the salt carrying rate reaches 80%,the carrier component will completely load the active ingredient,and the combination effect of the two is the best;Modified polydimethylsiloxane hydrophobic agent and moisture-proof silicone oil hydrophobic agent can provide good hydrophobic and slow-release effect for anti-ice materials,and the optimal content of hydrophobic functional components is 25%.Secondly,the phase composition,chemical composition,micromorphology and thermal properties of modified polydimethylsiloxane anti-condensation ice materials and moisture-proof silicone oil anti-condensation ice materials were tested and evaluated by X-ray diffraction(XRD),infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),thermogravimetric analysis(TG)and differential scanning calorimetry(DSC),and a low freezing point anti-condensation ice material with good performance was selected.p H test,density index test and freezing point test of preferred anti-condensing ice materials.The results show that the surface adsorption method will not cause the chemical reaction of the components of the anti-condensation material to fail,and the phase composition of each component remains good.The modified polydimethylsiloxane anti-ice material was supported with good active ingredient state and hydrophobic modification.When the temperature reaches 170°C,the mass loss of the material is about5%,and the overall thermal performance is good;The modified polydimethylsiloxane anticoagulant material has a p H value of 7～8,which is weakly alkaline,with a density of2.02g/cm~3 and a freezing point of-5.2°C.Thirdly,the modified polydimethylsiloxane anticoagulant ice material was replaced by the equal volume replacement method and the mineral powder filler was added to the asphalt mixture,and the warm mix asphalt mastic crushed stone asphalt mixture WSMA-10 system was used to test the road performance of the low freezing point anti-coagulation ice asphalt mixture under different replacement rates with high temperature stability,low temperature crack resistance and water stability as the indicators.The effective formation of anti-condensed ice was explored to analyze the influence on the road performance of asphalt mixture,and the optimal replacement rate of anti-condensed ice material was determined.The results show that with the increase of the substitution rate of anti-condensed ice materials,the high temperature stability and low temperature crack resistance of asphalt mixture are slightly reduced,and the water stability is greatly reduced.The precipitation of active ingredients has a great influence on the water stability of asphalt mixture.The optimal replacement rate of anti-condensed ice materials is 50%,and the road performance of low freezing point anti-condensed ice asphalt mixture with a replacement rate of 50%after simulation effective analysis still meets the specification requirements.Finally,the anti-coagulation performance of anti-coagulated ice asphalt mixture under the optimal substitution rate was evaluated by freezing point test,sponge pull-out test and ball drop test,and the results showed that the anti-coagulant ice asphalt mixture produced anti-condensation effect in the range of 0°C～-7.5°C.Combined with the above three anti-condensation performance test ideas and methods,this paper also modifies and designs a test device for testing the anti-condensation effect of anti-condensation ice asphalt mixture on the basis of the structure of the automatic rutting tester,and gives the corresponding test steps,in order to provide certain ideas and methods for the evaluation of anti-condensation effect.