Research On The Performances Of Crumb Rubber Composite Modified Asphalt Based On Rheological Properties

Crumb rubber asphalt technology promotes the green development,recycling development,and low-carbon development of transportation,which meets the construction requirements of resource-saving and environment-friendly transportation system.Using crumb rubber to modify asphalt has significant environmental and economic benefits.However,problems such as high construction temperature and poor storage stability of crumb rubber asphalt processed by traditional technology have restricted the popularization and application of crumb rubber asphalt.In order to solve the problem of uneven performance improvement of single crumb rubber asphalt and achieve a more ideal comprehensive performance,the crumb rubber asphalt was compounded through activation pretreatment of crumb rubber and addition of composite modifier to prepare different types of crumb rubber composite modified asphalt.Firstly,this paper studies the conventional properties and storage stability of crumb rubber composite modified asphalt.It is found that Sasobit played a role in reducing viscosity and drag,effectively improving the workability of crumb rubber asphalt.Two methods,which are Alkali treatment and addition of Bio-based Reinforcing Filler,have significantly reduced the difference of softening point and storage stability index SI of crumb rubber asphalt,which can be used as an effective way to improve the storage stability of crumb rubber asphalt.Secondly,using Dynamic Mechanical Analysis,this paper carried out the rheological performance analysis of crumb rubber composite modified asphalt at high,medium and low temperature;At the same time applying the time–temperature superposition principle,the wide frequency range rheological master curve based on CA model and improved CAM model was constructed to overcome the limitations of conditional evaluation and master the dynamic viscoelasticity of crumb rubber composite modified asphalt more comprehensively.The results show that the rheological master curve based on CA model and improved CAM model has a wide range of frequency and high fitting degree,which provides a way to accurately describe the dynamic mechanical response of crumb rubber composite modified asphalt;Crumb rubber composite modified asphalt generally has excellent high-temperature rutting resistance and fatigue cracking resistance,while its low-temperature performance is worse than that of virgin asphalt binder.Finally,the temperature sensitivity of crumb rubber composite modified asphalt was characterized by both empirical index and mechanical performance index of asphalt.The results show that the temperature sensitivity of the three types of crumb rubber composite modified asphalt is lower than that of virgin asphalt binder,and the crumb rubber can promote the improvement of the asphalt's temperature sensitivity.