| Based on the existing scientific and technological means and the development trend of materials,this paper attempts to introduce nanomaterials graphene oxide to blend SBS modified asphalt in order to optimize the problems such as poor compatibility and insufficient anti-aging performance of SBS modified asphalt commonly used in road construction.Furthermore,a systematic study was conducted on the graphene-SBS composite modified asphalt and mixture,with specific research as follows:Firstly,the effects of GO on the basic properties of SBS modified asphalt were analyzed through three index tests with different mixtures of composite modified asphalt as the test material.In terms of rheological properties of asphalt,temperature factor is the main entry point.Temperature scanning and multi-stress creep tests are used to study the ability of asphalt to resist deformation at high temperature and to recover elasticity.In order to evaluate the viscoelastic properties of composite modified asphalt under different load frequencies,the main modulus curve and glass transition temperature of asphalt were fitted by frequency scanning test and time-temperature equivalent principle.The stiffness modulus and creep rate were obtained through the creep test of the bending beam to analyze the rheological property of the composite modified asphalt in the aspect of cracking resistance at low temperature.The results show that GO can improve the high temperature deformation resistance of SBS modified asphalt by enhancing the high temperature delay elasticity and creep recovery properties of asphalt.Stiffness modulus and creep rate indicate that GO has little effect on low temperature performance.It is also found that the degree of influence of GO on rheological properties of asphalt is related to its dosage.After comprehensive analysis,it is suggested that GO dosage range is 0.50%-0.75%.The composite modified asphalt was studied from aging and fatigue.The effects of aging on the basic properties of asphalt samples were analyzed by comparing the asphalt test indexes under different aging degrees.The linear amplitude scanning test of asphalt was carried out on the premise of controlling different temperature and aging degree,and the fatigue life of asphalt was calculated based on the viscoelastic continuum damage model.The results show that GO can slow down the conversion of light to heavy components in asphalt,thus improving the anti-aging performance of asphalt.At the same time,the addition of modifier improves the anti-fatigue performance of SBS modified asphalt,and with the increase of temperature,the fatigue life of composite modified asphalt is extended to a certain extent,and the increase of load strain and aging effect will reduce the fatigue performance of asphalt under repeated load to a certain extent.The compatibility effect of GO on SBS modified asphalt was studied by fluorescence microscopy and segregation test,and the effect of GO on the chemical composition of asphalt was analyzed by infrared spectrum test.The results show that GO can enhance the crosslinked structure of SBS modified asphalt and reduce the softening point difference of SBS modified asphalt after segregation test,which shows that it has excellent compatibility.No new functional groups were generated during the modification of SBS modified asphalt by GO,which belongs to physical modification.The content changes of carbonyl group and sulfoxide group in the aging process of asphalt were analyzed,and it was found that GO could improve the anti-aging property of SBS modified asphalt.In the aspect of exploring the pavement performance of GO-SBS composite modified asphalt,the research results showed that GO could improve the high temperature rutting resistance and water damage resistance of SBS composite modified asphalt mixture,which had little effect on the low temperature performance,and significantly improve the anti-aging performance of the mixture. |
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