| Asphalt pavement,which is a major pavement form of high-grade and urban road,has many advantages of comfortable driving,convenient to rehabilitate and opening to traffic as quickly as possible.Some harmful situation will gradually emerge such as aging,decaying of performance,cracks in surface and water damage in Asphalt pavement,which leading to shorten its service life when subjected to the influence of light,oxygen and heat under natural environment.This passage mainly studies the estimating method and decaying law of aging performance of four common use of asphalt pavement,which offers significant theories in order to better prevent asphalt pavement from cracking caused by aging.Testing three major indicators,viscosity,DSR,IR,HNMR and microstructure of AFM of each testing samples choosing from 50#,70# and 90# Matrix asphalt and one SBS70# modified asphalt which have got 4 different kinds of aging degrees by using RTFOT respectively.Fitting and analyzing the conventional technical performance index and the DSR aging law depending on aging time,which is based on the aging experience index formula and aging dynamics equation and studying the aging law based on atoms and molecule in asphalt.Finally discussed the correlations of evaluating index of aging performance based on grey relational decision theory.The main research contents as follows:(1)With the increase of RTFOT aging time,the softening point and viscosity of matrix asphalt increased exponentially,and the penetration and ductility decreased exponentially.But the softening point of SBS70# modified asphalt changed according to the concave parabola,and the viscosity increased exponentially,the penetration and ductility decreased exponentially(2)The dynamic shear modulus G* and anti-rutting factor G*/sin(?)of each asphalt decrease with the increase of scanning temperature and tend to be gentle;at the same temperature,the anti-rutting factor G*/sin(?)of each asphalt increases exponentially with the increment of aging time;the critical temperature value of each asphalt increases linearly as the aging time increasing.(3)When the pavement asphalt ages,chemical reactions such as molecular isomerization,cracking and dehydrogenation occur,and oxygen-containing functional groups such as carbonyl and sulfoxide groups are formed,and the carbonyl content increases with the aging time.In addition,the SBS70# modified asphalt contains butadiene functional groups and unsaturated hydrocarbon protons;the surface roughness value of the asphalt is related to the size and quantity of the "bee structure",and the surface roughness value of the SBS70# modified asphalt is larger than the matrix asphalt.(4)With the increase of aging time,the aging rate of each asphalt is different according to the same performance index;and the aging rate sorting of each asphalt is different according to different performance indexes;Different technical indicators were used to evaluate the anti-aging properties of the same asphalt,and the results were inconsistent..(5)Based on the grey relational decision theory,the anti-aging performance of four kinds of asphalt was analyzed,and the size was ranked as SBS70#>50#>70#>90#,which indicated that the anti-aging ability of the three kinds of matrix asphalt was related to its label,the higher the label,the Lower the anti-aging ability,and SBS70# modified asphalt has better anti-aging ability than 3 kinds of matrix asphalt. |
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