Micromechanical Modeling Approach to Predict Compressive Dynamic Moduli of Asphalt Mixtures Using the Distinct Element Method

Abstract

A clustered distinct element method (DEM) approach is presented as a research tool for modeling asphalt concrete microstructure. The approach involves the processing of high-resolution optical images to create a synthetic, reconstructed mechanical model that appears to capture many important features of the complex morphology of asphalt concrete. Uniaxial compression tests in the laboratory were employed to measure the dynamic modulus of sand mastic (a very fine sand–asphalt mixture) and asphalt mixtures at three temperatures and four loading frequencies. For a coarse mixture considered in this study, it was found that a two-dimensional (2-D) clustered DEM provided good estimates of mixture dynamic modulus across a range of loading temperatures and frequencies without calibration. However, for a fine-grained mixture, the uncalibrated predictions of the 2-D model were found to reside near the lower theoretical bounds and well below experimentally determined moduli, most likely because of current limitations in scanning and modeling resolution and the nature of the 2-D microstructural description. Work is under way to extend the model to three dimensions and to consider linear viscoelastic behavior in the mastic. That notwithstanding, the current modeling approach was successfully implemented in recent follow-up studies to portray bulk material behavior in conjunction with fracture models to study crack behavior in hot-mix asphalt.

Experimental Testing and Finite-Element Modeling to Evaluate the Effects of Aggregate Angularity on Bituminous Mixture Performance

“…Some studies (Masad et al 2001;Papagiannakis et al 2002;Dai and You 2008) have proposed finite-element (FE) method-based models to characterize the damage performance of asphaltic composites. The discrete-element method (DEM), an explicit numerical technique, has also been employed by several researchers (Abbas and Shenoy 2005;You and Buttlar 2006;You et al 2009). These computational approaches allow engineers to better understand the mechanical effects of small-scale design variables (such as asphalt mastic film thickness, air voids in the mixture, size/ shape/distribution of aggregates, mineral additives in the mixture, volume fraction of asphalt mastics, etc.)…”

Quantitative Analysis on Force Chain of Asphalt Mixture under Haversine Loading

“…Sun et al proposed the criteria of strong force chain and angle and analyzed 2 Advances in Materials Science and Engineering the evolution of force chain structure morphology through simulating the uniaxial compression and biaxial test using the discrete element method [15,16]. You et al reconstructed the mesoscopic model of asphalt mixture and provided the force chain distributions within aggregates, within mastic, and between aggregates and mastic [17,18]. It can be found that the researches on force chains concentrate on the granular material with regular morphology, single particle size, and smooth edges by the literature cited above.…”

Investigation on Mechanical Properties of Bituminous Materials through 2D/3D Finite Element Numerical Simulations

“…(Lytton 1990); (Buttlar and Roque 1996); (Buttlar et al 1999); (Li and al 1999); (Shashidhar and Shenoy 2002); (Huang and al 2007); (Shu and Huang 2008); (You and Buttlar 2006). The generalized self-consistent model (GSCS) (Christensen and Lo 1979); (Christensen and Lo 1986) is recognized among the high sophisticated micromechanical model.…”