| In recent years,road construction has developed rapidly,and new materials are constantly developing and progressing.Traditional asphalt modified materials have many problems in the preparation process,molding process,economy and environmental protection.In this paper,a new type of nano-material bentonite is used as the modifier.First of all,the nano-bentonite modified asphalt was routinely tested,and its low temperature performance was poor.Therefore,three types of styrene-butadiene rubber(SBR for short)were added to the nano-bentonite modified asphalt by wet method for compound modification.After that,different types of nano-bentonite composite modified asphalts were subjected to routine physical tests for performance testing and storage stability experiments.Two suitable SBRs were selected for research.The study of the sexual mechanism has drawn its advantages and disadvantages in various aspects of performance.Then use dry method to prepare nanometer bentonite composite modified asphalt mixture,and test its road performance,and will open up a new road for new asphalt pavement materials.The research content of this article is roughly as follows:(1)The conventional physical properties and storage stability of nano-bentonite composite modified asphalt.Nano-bentonite-modified asphalt was prepared by interpolation method,and routine tests were carried out.The results showed that nano-bentonite had a negative impact on the low-temperature performance of the asphalt.Then conduct routine tests on SBR modified asphalt and nano-bentonite / SBR composite modified asphalt,and compare the results of the conventional test and stability test of nano-bentonite composite modified asphalt prepared by three types of SBR,Two composite modified asphalts with better effects are obtained.(2)The rheological properties and anti-aging properties of nano-bentonite composite modified asphalt mixed with SBR were systematically studied.Brinell viscosity test,film oven test,accelerated aging(PAV for short)test,dynamic shear rheological test,and bending rheological test are carried out on composite asphalt.By comparing the viscosity aging index of the asphalt and the complex shear modulus index,the anti-aging properties of the nano-bentonite composite modified asphalt are judged.Use PG classification to determine the high and low temperature performance of composite asphalt,the high temperature performance of the composite asphalt is judged by the complex shear modulus and phase angle,the fatigue resistance of the composite asphalt is judged by the rutting factor,and the low temperature rheology of the composite asphalt is judged by the S and m values,and finally the optimal content of SBR is determined.(3)Microstructure and mechanism of nano-bentonite composite modified asphalt.Observe the microstructure of composite asphalt and the distribution of nano-bentonite and SBR by scanning electron microscope(SEM for short),and determine the interaction between nano-bentonite,SBR and asphalt by the absorption peak intensity of infrared spectroscopy(FTIR for short),and by X-ray diffraction,based on the data measured by X-ray diffraction test(XRD for short),the line spacing between nano-bentonite and SBR in asphalt was calculated,and the compound type of nano-bentonite composite modified asphalt was determined based on the above test.(4)Road performance and gray correlation analysis of nano-bentonite composite modified asphalt mixture.Based on the orthogonal test,the optimal parameters of asphalt mixture molding for discontinuous gradation and continuous gradation were determined,and the road performance of SBR nano-bentonite composite asphalt mixture with different contents was tested,and then passed the gray correlation The degree of influence of different blending amounts of SBR on various road performances is ranked. |
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