Abstract
The paper aims to simulate the micromechanical behavior of asphalt mixtures during the compaction process using the Discrete Element Method (DEM). The interactions between the components of a Porous Asphalt (PA) mixture were represented using an Elastic Viscoelastic Contact Model (EVCM), which is a user-defined model implemented in EDEM software, developed based on linear elastic and Burger’s viscoelastic constitutive equations. The macroscale parameters of asphalt mortar were characterized using the nonlinear regression analysis of master curves obtained from Dynamic Shear Rheometer (DSR) tests. The verification process of EVCM successfully indicated that the computations trends fall within the range of expected values for the typical asphalt mixture material. Further, a Superpave Gyratory Compaction (SGC) test was carried out and the obtained sample was scanned using X-ray Computed Tomography (X-ray CT) to capture the air void distributions. The DEM was utilized where digital samples were established to simulate the overall process of laboratory and field compaction. The simulation results showed that the model provided a comparable prediction of responses and demonstrated the capability of SGC to fabricate a representative sample. The influence of temperature on the asphalt compaction process was explored and the results implied that temperature decreasing adversely affects the compactability and dramatically increases the demanded compaction efforts which are consistent with the law of viscoelasticity. On the contrary, when the temperature is high, the asphalt binder becomes too fluid and roller loads will simply displace, or “shove” the mat rather than compact it. Tracking the change in the air voids proportion indicates that the motion of aggregates is rather compound. The aggregates flowed vertically downwards in line with the compacting orientation while moved horizontally outwards away from the center. All in all, the findings confirm that the concept is technically practicable, affording the model great potential to help researchers understand the microstructural phases of asphalt mixture during the compaction.
Highlights
Over the past few years, clients in the pavement sector have become more aware of the importance of the accuracy and quality of the pro duction and construction phases of projects
The paper aims to simulate the micromechanical behavior of asphalt mixtures during the compaction process using the Discrete Element Method (DEM)
The influence of temperature on the asphalt compaction process was explored and the results implied that temperature decreasing adversely affects the compactability and dramatically increases the demanded compaction efforts which are consistent with the law of viscoelasticity
Summary
Over the past few years, clients in the pavement sector have become more aware of the importance of the accuracy and quality of the pro duction and construction phases of projects. This paper proposed a technique to develop a multi-physics model using DEM to simulate the compaction of a porous asphalt mixture in which the interaction between its components, the influence of tem perature and the contact law were considered. To achieve this goal, a Construction and Building Materials 301 (2021) 124305 new bonded-contact model, hereafter referred to as an Elastic Visco elastic Contact Model (EVCM), has been developed based on Burger’s and elastic constitutive equations [20,22,23,24]. It is noteworthy that EVCM can be perceived as a straightforward tool for simulating the mechanical performance of asphalt mixtures, helping to understand their behavior and gain in-depth knowledge about their microstructure during the compaction process
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