| In order to improve the pavement performance and prolong the service life of asphalt pavement,it is necessary to modify asphalt binder and study the performance of modified asphalt.This paper puts forward the modification of asphalt by polyuretheane resin,the modified asphalt was 70 # for three different types of polyurethane resin,first by comparing the change of asphalt penetration,softening point,ductility and other conventional performance indicators,determine the best dosage of polyurethane(PU)modifier.By comparing the performance of different types of PU modified asphalt system to obtain the best type of polyurethane resin.The compatibility of modified asphalt was studied by means of segregation test and fluorescence microscopy,the optimum content of compatibilizer in modified asphalt was determined.The viscosity temperature characteristics and storage stability of modified asphalt were studied by viscosity test,obtained the relationship between the viscosity temperature index(VTS)and PU modified asphalt mixing and compaction temperature,and pointed out that when the temperature is fixed,viscosity with time is almost the same and that of polyurethane modified asphalt has good storage stability.By means of force ductility test(FDT)the mechanical properties of the modified asphalt was studied,the results showed that polyether polyurethane(JM-PU)modified asphalt admixture of 11% best mechanical properties,and polyether modified asphalt with better mechanical properties than the other two types of modified asphalt.The aging properties of asphalt,with the softening point ?T,ductility ?H and viscosity retention rate of aging index VAI of modified asphalt anti-aging properties by rolling thin film oven test,the results show that JM-PU modified asphalt content is 11%,the best anti-aging performance.Compared with the other two kinds of modified asphalt,the anti-aging performance of JM-PU modified asphalt is better than that of other modified asphalt.Dynamic shear rheology(DSR)and Simple beam bending creep(BBR)tests were carried out to study the high temperature and low temperature performance of PU modified asphalt,the complex modulus,phase angle and rutting factor obtained by DSR analysis show that JM-PU modified asphalt has good high-temperature stability when the content is 11%,and the anti-rutting performance of modified asphalt is the best.In addition,the high temperature performance of JM-PU modified asphalt is better than the other two kinds of modified ashphlt.The fatigue temperature of JM-PU modified asphalt was analyzed,it was found that when the content of PU was 11%,the fatigue temperature reached the maximum value,and with the increase of the dosage,the fatigue temperature was basically stable.BBR test indicated that JM-PU modified asphalt has good low temperature performance,and the low temperature performance is the best when the dosage is 11%.By comparing the m value and S value of three types of modified asphalt,it was found that the low temperature performance of the three kinds of modified asphalt has a certain degree of improvement than the matrix asphalt,but the best effect is the JM-PU modified asphalt.By means of Fourier transform infrared spectroscopy(FTIR),the mechanism of PU modified asphalt was analyzed from the aspects of microstructure and chemical composition,the result show that the chemical reaction of PU modified asphalt system shows that PU modified asphalt is not only physical modification.The temperature stability of PU modified asphalt was analyzed by Differential Scanning Calorimetry(DSC),the results show that the DSC curve of JM-PU modified asphalt is flat and the temperature stability is good.The microstructure of asphalt before and after aging was analyzed by Atomic Force Microscope(AFM)test,the results show that the bee like structure of asphalt has changed before and after aging,and the adition of PU modifier can improve the dispersion of asphalt after aging.Finally,through the indoor experiment,the research of performance of modified asphalt mixture shows that polyurethane modified asphalt asphalt mixture high temperature performance,low temperature performance and water stability are better than the matrix asphalt,good high temperature performance of SBS modified asphalt mixture,but the low temperature crack resistance and water stability are better than SBS modified asphalt mixture. |
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