Abstract
The clump-based discrete element model is one of the asphalt mixture simulation methods, which has the potential to not only predict mixture performance but also simulate particle movement during compaction, transporting, and other situations. However, modelling of asphalt sand mortar in this method remains to be a problem due to computing capacity. Larger-sized balls (generally 2.0–2.36 mm) were usually used to model the smaller particles and asphalt binder, but this replacement may result in the mixture’s unrealistic volumetric features. More specifically, replacing original elements with equal volume but larger size particles will increase in buck volume and then different particle contacting states. The major objective of this research is to provide a solution to the dilemma situation through an improved equivalent model of the smaller particles and asphalt binders. The key parameter of the equivalent model is the diameter reduction factor (DRF), which was proposed in this research to minimize the effects of asphalt mortar’s particle replacement modelling. To determine DRF, the DEM-based analysis was conducted to evaluate several mixture features, including element overlap ratio, ball-wall contact number, and the average wall stress. Through this study, it was observed that when the original glued ball diameters are ranging from 2.00 mm and 2.36 mm, the diameter reduction factor changes from 0.82 to 0.86 for AC mixtures and 0.80 to 0.84 for SMA mixtures. The modelling method presented in this research is suitable not only for asphalt mixtures but also for the other particulate mix with multisize particles.
Highlights
In the past decades, the discrete element method (DEM) has been popularly used for simulating multisize particulate mixtures, such as asphalt mixtures, sands, graded stones, and chemically bounded mixtures [1]
Based on discrete element modelling, this paper generated a virtual specimen of asphalt mixture including aggregate, asphalt mortar, and air voids and deeply analysed mortar element overlap ratio and average wall stress in different diameter reduction factor (DRF)
The findings produced are as follows: After result analysis, the DRF ranges of mortar elements were recommended for different gradations
Summary
The discrete element method (DEM) has been popularly used for simulating multisize particulate mixtures, such as asphalt mixtures, sands, graded stones, and chemically bounded mixtures [1]. Fillers and asphalt are integrally simulated as asphalt sand mortar in two ways for different research goals: (1) mono-sized balls, which are the same as the cluster-based model, can be used for the purpose of mechanical behaviour prediction; (2) equivalent ball elements with same or similar diameters for the studying of particle movements during compaction or other stages. The clump-based model provides a way to study particle movements during the compaction stage, the challenging task is to find a potential solution to this dilemma situation: researchers prefer selecting larger size balls (2 mm or larger) to build the equivalent models of asphalt sand mortar for the higher computational efficiency This method is usually empirical and lacks quantitative analysis and verification, which will lead to the following problems: (1) since the ball-ball interactions in the equivalent models are different from those in the asphalt sand mortar, particle-interlocking effects may result in unrealistic mechanical responses. Suitable DRFs are recommended for different mixture gradations, and the results are verified in lab tests
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
