Study On Water Stability Of Asphalt Rubber Mixture In Seasonal Frost Region

In recent years,the widespread use of rubber asphalt mixtures has not only improved the road performance of roads,but also solved the problem of recycling used tires.Rubber asphalt has obvious advantages in tests such as high temperature stability,low temperature brittle cracking performance,fatigue performance,temperature and light aging performance,water damage performance,etc.It is suitable for the low temperature environment of the cold season in the northeast of China's seasonal frost region.The use of rubber asphalt surface layer can effectively reduce the occurrence of low temperature cracks on the road surface,delay the occurrence of road damage and disease,and extend the service life.With the economic development,the demand for road traffic has also increased,and the utilization rate of the rubber asphalt mixture surface layer has gradually increased.When the rubber asphalt pavement that has accumulated water is damaged by the cyclic load of the vehicle and the freeze-thaw cycle,the pavement will have a phenomenon of dropping,loosening,and peeling.This phenomenon is called water damage of the pavement.How to make better use of rubber asphalt mixture and avoid roads being prematurely damaged by water has certain theoretical significance and practical application value.Therefore,this paper conducted an experimental analysis on how to reasonably improve the water stability of the asphalt mixture in seasonal frost region.First of all,this paper conducted a laboratory test study on the basic performance indicators such as penetration,ductility,softening point,elastic recovery and adhesion of rubber asphalt and Liaohe 90 # asphalt.The low temperature penetration,low temperature ductility and low temperature elastic recovery tests were carried out mainly according to the environmental characteristics of the northeast seasonally frost region,and it was concluded that rubber asphalt has a high and low temperature penetration and low temperature ductility compared with Liaohe 90 # Good,low temperature elastic recovery ability.Secondly,the modification mechanism of rubber asphalt was analyzed.Based on this theory,the water stability of rubber asphalt mixture was tested and analyzed.The basic road performance parameter test of raw materials was carried out: basic performance tests were conducted on raw materials such as rubber asphalt,aggregates,fillers,and admixtures,and the results met the basic requirements of the current specifications.And the AR-AC-13 and AR-SMA-13 rubber asphalt mixtures commonly used in the northern region are selected for gradation design.On this basis,this paper conducts experimental research on the main factors affecting the water stability of rubber asphalt mixtures: void ratio,rubber powder content and oil-rock ratio.In this paper,we will analyze the influence of porosity on the water stability of rubber asphalt mixtures in terms of the main factors of porosity.Indoors,the same mix ratio of AR-AC-13 and AR-SMA-13 asphalt mixtures in different voids The water stability test of the asphalt mixture was carried out under the condition of the rate.Finally,combined with the climatic characteristics of the seasonally frozen areas in the north,the two asphalt mixtures AR-AC-13 and AR-SMA-13 were subjected to freeze-thaw split test and immersion rutting test,respectively.The test results show that under the same gradation,the change of the porosity of the rubber asphalt mixture has a greater impact on its water stability.The porosity in the appropriate interval will make the rubber asphalt mixture itself have better water stability,otherwise it will The water stability is reduced,and the reasonable porosity range of the mixture is analyzed.Then,the AR-SMA-13 asphalt mixture was selected to pass the freeze-thaw splitting test.The freeze-thaw splitting strength ratio TSR was used as a parameter to analyze the influence of the rubber powder content and the bitumie-aggregate ratio on the water stability of the mixture.In the field construction,the void ratio of the rubber asphalt mixture is also a reflection of the degree of compaction.This paper can provide a reference for how to use a reasonable roller compaction to obtain a standard degree of compaction during road construction in the future.