Study On The Technology Of The Salt Anti-freezing Pavement

It will not only seriously affects the traffic efficiency but also the traffic safety when the asphalt pavement accumulates snow and gets frozen in winter.The salt anti-freezing asphalt pavement is a new type of pavement,which can achieve the goal of snow melting and anti-freezing effect by adding materials that can lower the freezing point.In this paper,the gradation design,pavement performance,anti-freezing evaluation indexes,resistance to freezing persistence and the mesoscopic structure of salt anti-freezing asphalt mixture are studied.In this paper,the feasibility of bitumen mix design by using the target porosity as the control index and the volume substitution method of salt compounds was established.The effects of various factors on the road performance of anti-freezing pavement were analyzed by alternating the soaking temperature,the soaking time and the salt content,and by using the proportion of salt solution and the porosity as the evaluation indexes.The freezing point of the solution was determined as the evaluation index of the anti-freezing performance of the salt anti-freezing asphalt pavement,and the relationship between the freezing point and the salt content was established.Based on the specific atmosphere and precipitation of the project location,a flooding test was designed to analyze the dissolution of the salt anti-freezing asphalt pavement,and the freezing durability was calculated quantitatively.The method of computed tomograph(CT)non-destructive testing was used to analyze the mesoscopic structure of the salt anti-freezing asphalt mixture and the improved maximum annular variance algorithm(OTSU)was used to divide the pores of the specimen.The effects of the salt content and freeze-thaw cycles on the mesoscopic structure of the salt anti-freezing asphalt mixture were compared,and the developing trend of the mesoscopic structure was analyzed.Combine the pavement of the test road,this paper summarizes the precautions of the salt anti-freezing asphalt mixture in the construction process.The study shows that the main factor causing the damage of the salt anti-freezing asphalt pavement is high temperature water environment.The anti-freezing persistence period of the anti-freezing asphalt pavement was 4.18 years in Qinhuangdao when the indexes of anti-freezing evaluation was used at-0.3 ?.The deliquescence of salt in the asphalt mixture is the direct cause of the change of micro-pore structure in the case of high temperature.The damage of the salt anti-freezing asphalt pavement will greadly accelerate the decline of road performance.The research results of this paper have important engineering value and practical significance.