The Research On The Asphalt Mixture That Utilizing The Combination Physical And Chemical Interactions To Melt Ice And Deice

When winter comes the roads are covered with snow and ice,and it causes the reduction of pavement anti-skidding and serious traffic accident,so it has become a big problem of affecting traffic negatively and threating the driving safety.Therefore,nations' traffic department and scholars in road field have paid their close attention to find scientific and effective methods to remove snow and ice on the pavement surfaces.This paper researched one kind of physical&chemical snow-melting and de-icing Asphalt Mixture which was shortly called PCAM and rubber particles and anti-freezing material were added into this pavement structure at the same time.And PCAM combined the respective advantages of asphalt pavement with snow-melt salt and elastic deicing pavement so as to enhance the deicing and snow-melting efficiency of mixture,meanwhile,to save snowmelt agent and consume the black trash waste tires.It is one scientific and environmental friendly pavement deicing technology with social value.The paper firstly designed the mixture ratio of PCAM,then evaluated its basic road usage performance and finally estimated its performance of melting snow and deicing.In order to guarantee the structural stability of PCAM as well as the deicing function,the skeletal compacting mixture structure was chosen and volume design procedure based on multilevel dense build-in gradation was used to design the mineral aggregate gradation.Then rubber particles partly replaced the corresponding graded aggregate with equal volume,at the same time the partial mineral powder was replaced by anti-freezing agent IceBane with equal volume.The final formed grading was named PCAM-13.Then the optimum asphalt-aggregate ratio was determined as 6.2%.The paper also explored hot-mix process of PCAM and used second molding to improve the difficulty of compaction caused by rebound.After mix proportion design,the basic road performance of PCAM should be evaluated.And we came to the conclusion that the high-temperature stability,lowtemperature crack resistance and moisture stability of PCAM all could satisfy the requirement of specification when rubber particle content was no more than 4% and no less than 2% and freeze inhibitor dosage was between 4% and 6%.But the three kindsof performance were increased with the increase of freezing inhibitor content and with the increase of rubber particle content the moisture stability of PCAM dropped,the high-temperature stability and low-temperature crack resistance improved at first and then decreased.As for the evaluation of PCAM's performance of snow melting and deicing,firstly a simple freeze inhibition experiment was carried out and then we could observed the anti-freezing effect was obvious,and measured the temperature range with good anti-freezing effect was-12? to 0?.The compressive resilience modulus at low temperature was used to represent the elastic deicing capability of PCAM in cold environment.The smaller the resilient modulus of elasticity was the better the elasticity of mixture would be.The results showed that the incorporation of rubber particles could effectively improve the elasticity of asphalt mixture,and the improving effect was more pronounced at low temperatures than at room temperature.The evaluation of PCAM's chemical melting ice performance was carried out by immersion rutting test and short-term melting ice experiment.Immersion rutting test is an experiment that used the rutting tester to roll PCAM specimen which was soaked in twenty-five degrees Celsius water,and rubber particles content of PCAM was 3% and antifreeze agent content of PCAM varied.Next measured the resistivity of the water in which the test pieces soaked to characterize the variation of the salt dissolve out from the specimen.The results of the experiment proved that when the antifreeze agent content increased the effective melting-snow salt dissolve more out from the specimen at same rolling time.Moreover,placed ice block of different thickness on the PCAM Marshell specimen surface,observed the short-term(2 hours)melting-ice effect when the specimens were placed in different temperature.The results showed that the ice melted more slowly at lower temperatures,the melting-ice rate of PCAM in different temperature could be calculated according to ice quality-time curve.Finally the paper evaluated the physical and chemical comprehensive deicing performance of the PCAM by rutting tester rolling specimen to deice.Study how the temperature and ice thickness influenced the deicing effect of PCAM specimens and came to the conclusion that the physical and chemical comprehensive deicing effect of PCAM became very weak when temperature was below-15? and ice thickness was more than 10 mm.It was due to elasticity of PCAM decreasing because of lower temperature and strength of ice enhancing with larger forming thickness.Generally speaking,the physical and chemical comprehensive deicing function of PCAM wouldbe impacted by environment temperature,snowfall(ice layer thickness),load strength and other factors.Eventually used vehicle to roll the PCAM specimens with ice layer outdoor and then observed its deicing effect.We obtained the outcome that the ice layer on PCAM specimen surface broke into pieces and had removed from the specimen but the ice layer on SMA specimen surface did not have any changes.The results proved that PCAM had very prominent advantages of removing snow and ice from pavement than ordinary asphalt mixture.