Experimental study on fatigue and self-healing performance of two kinds of asphalt mortar

In order to study on the fatigue and self-healing characteristics of asphalt mortar, the dynamic shear rheometer (DSR) was utilized to test time sweep and fatigue-healing-fatigue, and the microstructure was observed by Atomic Force Microscopy (AFM), and the fatigue performance of asphalt mortar and styrene butadiene styrene block copolymer(SBS) modified asphalt mortar under different powder binder ratios and self-healing properties of 3 different intermittent periods at normal atmospheric temperature (25℃) were analyzed and compared. It's found that SBS asphalt mortar has better fatigue and self healing properties, the fatigue life of two kinds asphalt mortar increases with powder binder ratio, and longer intermittent period is beneficial to self-healing under the same powder binder ratio. AFM observations show that matrix asphalt mortar appears "bee like structure" obviously, and asphaltene is absorbed and "bee like structure" becomes more, so the cohesion between filler and asphalt is enhanced, and fatigue properties is also improved with the increase of powder binder ratio. SBS modifier has good compatibility with asphalt, not a "bee like structure", and the addition of the modifier greatly enhances the cohesion between the molecules, also it is conducive to improve the fatigue properties, so it is recommended that modified asphalt mortar is used as pavement material.