Study On The Effect Of Water On Permanent Deformation Of Asphalt Mixture

Rutting which has the greatest probability of occurrence is one of the many diseases in our country's high-grade highway,it is very obvious in high temperature and rainy areas.While reducing the quality of asphalt pavement,rutting much directly affects other functions of the pavement.The emergence of rutting is closely related to the factors such as the driving load,loading time,the environment temperature,the geographical condition and so on.At present,there are few researches on the permanent deformation of asphalt mixture under the influence of water.By this problem,considered about the existing experimental conditions,this paper analyzes whether the high temperature stability of asphalt mixture that under the condition of water is changed,which is based on the permanent deformation tests of repeated loading.In this paper,the mechanism of the permanent deformation of asphalt mixture that under the influence of water is analyzed from two aspects which are asphalt stripping and water movement path.This paper analyzes the factors influencing the permanent deformation of asphalt mixture,and puts forward some measures to improve the high temperature stability of asphalt mixture.Repeated loading permanent deformation tests have been done respectively on the specimens in different water-holding conditions(non-water,saturated water immersion and freeze-thaw cycle)which are made by AC-20 and AC-25 asphalt mixture.By changing the test temperature and loading stress,we acquire the curves of permanent deformation in different water-holding conditions of asphalt mixture.Through analyzing the permanent deformation curves of different load pressure,different temperature and different water-holding conditions,it is suggested that the permanent deformation increases with the increasing of the load pressure and the temperature,and the existence of water decreases the high temperature stability of the asphalt mixture.However,the effect of different water-holdings on the permanent deformation performance is different,the effect of freezing and thawing cycle appears to be the greatest,followed by saturated water immersion.CoMPared with the permanent deformation curves of AC-20 asphalt mixture,AC-25 as the coarse gradation asphalt mixture is resistant to permanent deformation well.Viscoelastic model of permanent deformation in different water-holding conditions is deduced based on the modified Burgers constitutive model.Carrying out quantitative analysis and evaluation on the results of permanent deformation test of asphalt mixture in different water-holding conditions by using the MATLAB programming,the results show that the correlation coefficient of test data in any water-holding condition is above 0.99,and the existing permanent deformation viscoelasticity model can well describe the permanent deformation law under different water-holding conditions,Based on the interpolation of the existing data,we obtain the 3D model of permanent deformation under different water-holding conditions at last.Through the mechanism analysis of permanent deformation and the different effect on permanent deformation of mixture under different water-holding conditions,to establish a prediction model of permanent deformation of asphalt mixture under the condition of water,and provide the basis for the life prediction of asphalt pavement in high temperature and rainy areas,and it also has important reference value for preventing and controlling the disease of asphalt pavement and improving the maintenance of asphalt pavement.