Investigation on internal mechanical response of asphalt mixture during creep test utilizing the Smart Aggregate

Abstract

• Internal mechanical response of asphalt mixture to the creep behavior was investigated using Smart Aggregate. • Effects of particle location, stress level and temperature on the internal mechanical response were analyzed. • Relationship between internal mechanical response and creep behavior was discussed for asphalt mixture. The micro-mechanical behaviors of asphalt pavement play the essential role in its macro-mechanical properties and damage evolution. However, the efforts to research the micro-mechanical mechanism of asphalt mixture are still not enough, especially from a particle level in the laboratory. This study aims to investigate the internal mechanical response of asphalt mixture to the creep behavior with the assistance of built-in Smart Aggregate. After calibrating the force measurement for the Smart Aggregate, it was embedded in the asphalt mixture to monitor the inter-particle forces during the uniaxial static creep tests. Meanwhile, various test conditions, including particle location, stress level and temperature, were concerned to analysis their influences on the mechanical response of the Smart Aggregate. In addition, the relationships between internal mechanical responses and creep behavior were discussed. Results indicate that the applied force has a nonlinear relation to measured voltage of the Smart Aggregate, and can be obtained according to the regression model after calibration. During creep test, the Smart Aggregate performs well in acquiring the internal mechanical response of asphalt mixture. The inter-particle forces show uneven along the direction of loading stress during the creep test in asphalt mixture. The measured force increases monotonously whilst the strain increasing during creep evolution. Regarding the same temperature, there are significantly linear relations between instantaneous elastic modulus and measured force at the beginning and between eventual stiffness modulus and measured force at the end in dual logarithmic scales. Meanwhile, the slope k f of force curve in the steady shows strongly linear relation to the slope k s in equi-velocity creep stage on the Cartesian coordinates.