Application of Nonlinear Differential Dynamic Model to Evaluate Long-Term Aging Behavior of SBS Modified Asphalt

In order to study the long-term aging behavior of SBS modified asphalt, a nonlinear differential dynamic model was developed and the aging tests with rolling thin film oven test (RTFOT) for SBS modified asphalt were carried out. The dynamic model was developed referring to the population developing model with two parameters, namely average aging rate and aging ratio. And the differentiation of the dynamic model was the aging rate equation with which can calculate the aging rate at any time. The aging tests with RTFOT for SBS modified asphalt at different times were carried out and the penetration, ductility at 5°C, softening point and viscosity at 135°C were measured after RTFOT. With the rest results, the two parameters of nonlinear differential dynamic model of above four indexes were determined, and further the aging rate equations were deduced. The research results show that the nonlinear differential dynamic model can exactly describe the varying behavior of penetration, ductility, softening point and viscosity of SBS modified asphalt after RTFOT aging test with different time. The aging rate reach maximum value at the beginning and becomes smaller and smaller as the time goes.