Generation of 3D representative volume elements for heterogeneous materials: a review

Sustainable and resilient pavement infrastructure is critical for current economic and environmental challenges. In the past 10 years, the pavement infrastructure strongly supports the rapid development of the global social economy. New theories, new methods, new technologies and new materials related to pavement engineering are emerging. Deterioration of pavement infrastructure is a typical multi-physics problem. Because of actual coupled behaviors of traffic and environmental conditions, predictions of pavement service life become more and more complicated and require a deep knowledge of pavement material analysis. In order to summarize the current and determine the future research of pavement engineering, Journal of Traffic and Transportation Engineering (English Edition) has launched a review paper on the topic of “New innovations in pavement materials and engineering: A review on pavement engineering research 2021”. Based on the joint-effort of 43 scholars from 24 well-known universities in highway engineering, this review paper systematically analyzes the research status and future development direction of 5 major fields of pavement engineering in the world. The content includes asphalt binder performance and modeling, mixture performance and modeling of pavement materials, multi-scale mechanics, green and sustainable pavement, and intelligent pavement. Overall, this review paper is able to provide references and insights for researchers and engineers in the field of pavement engineering.

New innovations in pavement materials and engineering: A review on pavement engineering research 2021

Intermediate-depth brecciation along the subduction plate interface (Monviso eclogite, W. Alps)

Computational homogenisation from a 3D finite element model of asphalt concrete-linear elastic computations

To make the road infrastructure more competitive and sustainable, a long-term transition to cold asphalt technologies, especially those which involve bitumen emulsions is necessary. However, to minimise the compromise on mechanical performance compared to the conventional technologies, the objective of this research was to propose a comprehensive method for evaluating the contribution of the bitumen emulsion to the asphalt mixture properties. The variable influence of the aggregate was eliminated by standardising the aggregate composition of bitumen emulsion mortar (BEM), and the BEM mixtures were tested with various emulsion-related parameters. The change in physical and indirect tensile test-based mechanical properties was measured over time on statically-compacted cylindrical specimens in pre-defined curing conditions. Almost the entire change in physical and volumetric properties occurred in the first 28 days of curing. As a rule, the mixtures with higher emulsion content were more sensitive to the bitumen viscosity, and the harder bitumens resulted in higher indirect tensile strengths. The measured change in the bulk densities and the voids over time was compared with calculated theoretical values to which the lowest emulsion contents had the fastest convergence. Furthermore, coefficients for estimating the mechanical parameters based on the 28 day-reference values were determined, and the standard BEM mixture composition was adopted. Finally, this evaluation approach showed a good potential of becoming a standard method for testing and improving the bitumen emulsion properties.

Characterising the influence of bitumen emulsion on asphalt mixture performance

Nonlinear modeling and computational homogenization of asphalt concrete on the basis of XRCT scans

The present contribution is concerned with the requirements of an efficient multi-scale modelling approach for elastic/viscoelastic compounds such as bituminous asphalt concrete. Typically, this heterogeneous composite material consist of a mineral filler (e.g. crushed rock), a bituminous binding agent, pores and further additives. The contrast in stiffness between the different is extremely high and accounts for several orders of magnitude. Prediction of effective mechanical properties of such complex materials on the macroscopic level requires a detailed knowledge of the micro-scale behaviour of the particular constituents. In this study, we will focus on modelling aspects due to upscaling routines based on volume averaging. Particularly, we will show that the choice of micro-level boundary conditions not only influences the effective stiffness of the viscoelastic substitute material (upper/lower limit), but also the viscous contribution to the macro-model (shift of maximal attenuation in frequency space). In order to study these fundamental homogenization properties, we introduce a simplified compound consisting of homogeneous viscoelastic binder phase and spherical filler particles with a volume fraction low compared to realistic asphalt concrete. Depending on the chosen boundary condition, stress-relaxation and creep tests are considered. After transformation of the effective stress-strain-relations from time- to frequency space, the viscoelastic properties of the compound will be discussed in frequency domain.

Multi-scale modelling of elastic/viscoelastic compounds

https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.201710212

Computational generation of statistical volume elements of biphasic asphalt concrete and its material behavior

This paper will give a short overview about a multi-scale modelling approach for bituminous asphalt concrete. The goal is to describe the micro-heterogeneous medium by a homogeneous surrogate medium, which has similar effective mechanical properties. Starting from the varying constitutive behaviour on the micro-scale, our up-scaling procedure is realised via volume averaging techniques. By use of a Finite-Element model, the results for different types of boundary conditions (BCs) and their influence on the properties of the compund are investigated on the effective scale. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.201210155

Thorsten Schüler

Papers

Nonlinear modeling and computational homogenization of asphalt concrete on the basis of XRCT scans

Multi-scale modelling of elastic/viscoelastic compounds

Computational generation of statistical volume elements of biphasic asphalt concrete and its material behavior

Bituminous asphalt concrete: Aspects on scale‐bridging