Research On The Anti-aging Performance Of Asphalt And Its Mixture Modified By GO And LDHs

Asphalt binder will be aged by factors under the condition of high temperature production and natural environment during service process,such as heat,light and oxygen.It makes asphalt become harder,leads to early disease and reduces service life span of pavement.Therefore,it has the important significance to prolong the service life span of the asphalt pavement by improving the anti-aging performance of asphalt.Inorganic nano-materials with layer structure are excellent barriers for oxygen,which can be applied to improve the anti-aging performance of asphalt.However,the compatibility between inorganic materials and asphalt is poor,causing that inorganic materials are difficult to be well dispersed in the asphalt.Thus,this problem decreases the blocking performance and reduces the modified effect on the durability of asphalt.Graphene oxide（GO）and organic intercalated Layered double hydroxides（BI-LDHs）not only have unique layer nanostructures,but also have good compatibility with asphalt.Therefore,GO and BI-LDHs can be used to improve the anti-aging performance of asphalt.It can provide theoretical and technical support for inorganic nano-materials layer structure material to prepare asphalt pavement materials with anti-aging performance by study of the anti-aging performance and modification mechanism of the GO and BI-LDHs on the structure,road performance and anti-aging performance of asphalt and mixture.In this paper,used the modern test methods,such as the GC-MS,the ranman spectroscopy,the TLC-FID and so on,to analyze the material properties of the GO and BI-LDHs aging resistant modifiers,and studied the structural features in the asphalt and the influence of the modifiers on asphalt chemical composition structure.Studied the change of asphalt colloid structure,physical properties and rheological properties before and after the thermo-oxidative aging test（TFOT,PAV）or the UV aging test,comparative studied the GO and BI-LDHs aging resistant modifier effect on the pavement performance and anti-aging property of the asphalt.Finally,the improvement of GO and BI-LDHs anti-aging modifier on the pavement and anti-aging properties of asphalt mixture was studied.The main research conclusions can be drawn as follows:（1）Fom the research on the microstructures,we can be found that the GO and the BI-LDHs are evenly dispersed in the asphalt,which is beneficial to obstruct the permeability of light and oxygen.And,the segregation softening point difference of the GO and BI-LDHs aging resistance modifiers modified asphalt are all less than0.5°C,so these two kings of asphalts have good storage stability.（2）The effects of the GO and BI-LDHs on the contents of the asphalt four components are not significant,but the lamellar structures restrict the freedom movement of asphalt molecular,which causes the asphalt to be harder and enhances the high temperature rutting resistance performance.However,at the temperature of higher than 100°C,the GO in the asphalt will start to release the CO₂ gas,the asphalt volume will expand so that decrease the viscosity of asphalt,and decrease the mixing temperature of asphalt.The GO can also reduce the G*in the range of the low temperature and improve the low temperature resistance of asphalt.（3）The GO and the BI-LDHs can decrease the conversion ratio of the light components to heavier components and gelatinization index in the process of the thermo-oxidative aging and the UV aging,these two modifers can alleviate the hardening of asphalt during being aged.The anti-aging performance of the asphalt will be incresed with the increase the GO and the BI-LDHs contents.At the same dosage,the improvement effects of the GO on the anti-aging performance of asphalts are better than that of BI-LDHs.（4）After adding the GO and the BI-LDHs,the high temperature performance of asphalt mixture will be increase,and the anti-aging performance of asphalt mixture will be improved.At the same dosage,the improvement effects of the GO on the anti-aging performance of asphalt mixtures are better than that of the BI-LDHs.（5）GO and BI-LDHs mainly through the three ways,namely the absorption effect of light component in the asphalt,the blocking effect of the oxygen（UV light）and volatile components,and delay the ageing reaction rate of the asphalt duiring aging process,to improve the anti-aging performance of the asphalt.