Study On Rheological And Anti Aging Properties Of Organic Montmorillonite/SBS Composite Modified Asphalt

Styrene-butadiene-styrene(SBS)is widely used in asphalt modification,but the properties of SBS modified asphalt after aging are greatly reduced.How to improve the road performance of SBS modified asphalt after aging has become an urgent problem to be solved.Organic montmorillonite(OMMT)has attracted the attention of researchers due to its unique layered structure and good mechanical property.In order to explore the effect of OMMT content on the rheological properties and anti-aging properties of SBS modified asphalt,the indoor simulated aging test was carried out.In the above tests,this studied the basic performance,rheological performance and anti-aging performance of OMMT/SBS composite modified asphalt before and after aging.The main research works are as follows :Firstly,three basic performance tests of softening point,penetration and ductility before and after aging were carried out.The preliminary results showed that the high temperature performance and anti-aging performance are improved after adding OMMT,and the low temperature performance was decreased.Secondly,we studied the rheological properties of OMMT / SBS composite modified asphalt under different aging degrees by dynamic shear rheometer(DSR)and bending beam rheometer(BBR).The complex modulus master curve was constructed by Sigmoidal model and WLF equation.It explored the influence of different OMMT content on the high temperature performance of asphalt in a wide frequency range.The results showed that the high temperature performance is improved significantly when the OMMT content was 3 %.Then,we discussed the influence of different OMMT content on the medium temperature fatigue performance of asphalt through the fatigue factor,stress-strain curve,VECD model parameters and fatigue life.The results show that the fatigue performance increases with the increase of OMMT content.After that,based on the BBR test,the Burgers model was used to analyze its low temperature performance from the perspective of viscoelasticity.The results showed that the OMMT content has a greater adverse effect on the low temperature performance when the OMMT content was 5 %.At the same time,it was found that the relaxation time is more suitable for evaluating the low temperature performance of OMMT /SBS composite modified asphalt.Furthermore,the anti-aging properties of OMMT / SBS composite modified asphalt were analyzed from a macro perspective by calculating the rheological aging index.Meanwhile,we analyzed the anti-aging performance of OMMT / SBS composite modified asphalt from the microscopic point by infrared spectroscopy(FTIR)technology.It demonstrated the aging index of carbonyl and sulfoxide groups of aged OMMT / SBS composite modified asphalt decrease.After adding OMMT,the aging resistance of asphalt was improved.Finally,the improvement of asphalt performance should be reflected in the road performance of the mixture.Therefore,the road performance test of OMMT / SBS composite modified asphalt mixture before and after aging was carried out.That proved that the addition of OMMT can effectively improve the high temperature stability,water stability and anti-aging performance of asphalt mixture.