| Tack coat is in the transition position of pavement interlayer,which play an interim function,as well as possess waterproofness.Researches show mostly early damage of the asphalt pavement surface has a direct relationship with the quality of tack coat.Design,construction,material factors,climate and traffic conditions will have an effect on the cohesive force of tack coat,and selection of adhesive layer asphalt material is one of the important factors influencing cohesive force of the tack coat.Especially in southern,temperature in summer is high and last long.If high temperature properties and bonding performance of tack coat asphalt material is poor,asphalt will flow easily in high temperature which led to the decrease of bonding ability.Based on a large number of relevant literature,according to rheology principle,A-50#、SK-70#basic asphalt,SBS modified asphalt,CRM modified asphalt,four kinds of tack coat asphalt materials were made high temperature dynamic shear test,temperature sweep,viscosity testing,shear fatigue performance test using dynamic shear rheometer(DSR).Research shows that,as the asphalt layer material,SBS modified asphalt and CRM modified asphalt much better than A-50#and SK-70#basic asphalt in the high temperature stability,the dynamic mechanical properties,cohesive property and shear fatigue performance,etc.When SBS modified asphalt as tack coat material,it is necessary to choose basic asphalt had better compatibility with modifier SBS matrix to get good fatigue performance.And CRM modified asphalt 135 ℃ viscosity is too large to spreading.Focused on the performance requirement for tack coat asphalt material,using SK-70#as basic asphalt and SBS、CRM、SR as modifiers,a composite modified asphalt tack coat material was preparation indoor by high-speed shear method.Based on high temperature properties and bonding performance of tack coat asphalt,indoor preparation technology of composite modified asphalt was optimized.Through conventional index test,high temperature dynamic shear test,dynamic mechanical properties and viscosity test,the best modifier dosage of compound modified asphalt tack coat material was determined.Finally,pavement performance of the prepared composite modified asphalt material was evaluated.research shows that composite modified asphalt material displays good high temperature performance,dynamic mechanical properties,the adhesive properties,and spilling temperature of composite modified asphalt could down by adding SR,which is benefits to spraying. |
