Untersuchung des meso-mechanischen Verhaltens von Asphaltbefestigungen basierend auf meso-strukturierten numerischen Simulationen
Investigation on the mesomechanical performance of asphalt pavements based on mesostructured numerical simulations
Asphaltbeläge zeigen komplexe lineare und nichtlineare mechanische Reaktionen bei Verkehrsbelastungen. Im Vergleich zu konventionellen Experimenten, können mesostrukturierte numerische Simulationen einen tieferen Einblick in die internen Mechanismen des linearen und nichtlinearen Verhaltens von Asphaltmischungen geben. Basierend auf der zweidimensionalen (2D) Multiskalensimulationen wurde die lineare Viskoelastizität von Asphaltbelägen mithilfe der Finite-Elemente-Methode effektiv vorhergesagt. Darüber hinaus wurden das thermodynamische Schädigungsverhalten von Asphaltbelägen, die Rissentstehung und -ausbreitung durch Anwendung des Kohäsionszonenmodells (CZM) dargestellt. Die durch die heterogenen Mesostrukturen verursachten Rechenzeit- und Konvergenzprobleme sind jedoch nicht zu vernachlässigen. Um die Effizienz der Simulationen zu steigern, wurde ein neuartiges mesostrukturiertes Modell mit der Bezeichnung "Lokal Homogenes Modell" entwickelt und erfolgreich in zwei- (2D) und dreidimensionalen (3D) Simulationen angewendet. Es wurde ein neuartiges lokal homogenes Modell zusammen mit lokalen Homogenisierungsansätzen erarbeitet, um das lineare und nichtlineare Verhalten von Asphaltbelägen mit unterschiedlichen Gesteinskörnungen zu simulieren. Anhand mehrerer Fallstudien werden die Validität der vorgeschlagenen Modelle und Ansätze belegt. Zukünftig gilt es, die Wirksamkeit der lokal homogenen Modelle in Asphaltbelag-Simulationen mithilfe von Feld- oder In-situ-Tests zu erforschen. (A) ABSTRACT IN ENGLISH: Asphalt pavements perform complex linear and nonlinear mechanical responses with respect to traffic loadings. Compared with traditional experimental approaches, the mesostructured numerical simulations can afford a deep insight into the internal mechanism of linear and nonlinear behavior of asphalt mixtures. Based on the two-dimensional (2-D) multiscale simulations, the linear viscoelasticity of asphalt pavements was effectively predicted using the finite element method. Furthermore, the thermodynamic-damage behaviors of asphalt pavements, crack initiations, and propagations were demonstrated by incorporating the cohesive zone model (CZM). However, the computational time and convergence problems caused by the heterogeneous mesostructures cannot be neglected. To improve the efficiency of the simulations, a novel mesostructured model named the “locally homogeneous model” was proposed and successfully applied in two-dimensional (2-D) and three-dimensional (3-D) simulations. The models were divided into several local cells according to the location and size of the aggregates. In each local cell the aggregate and surrounding asphalt matrix were homogenized based on the Mori-Tanaka (MT) method. In terms of the random generation algorithm, the developed locally homogenous model can account for various asphalt mixtures with different aggregate gradations, e.g., dense-graded mixture (AC) and gap-graded mixture (SMA). In the abovementioned model developments, the linear viscoelasticity and elasticity were respectively specified for asphalt mortar and aggregate, and the nonlinear behavior was represented by inserting numerous CZMs. Therefore, the CZMs induced discontinuous crack initiations and propagations, and further caused a large amount of computations efforts and convergence problems. To address this issue, this research proposed a homogenization approach for the nonlinear viscoplastic and damage properties based on the MT method. This approach regards composite materials as homogeneous structures, and represented their nonlinear behaviors by employing the internal state variables. A laboratory creep-recovery test was conducted to determine the linear viscoelasticity and nonlinear viscoplasticity of asphalt mortar. Combined with the locally homogenous model, the nonlinear behavior of asphalt mixtures consisting of different aggregate gradations (AC and SMA) were effectively demonstrated.In summary, comprehensive mesostructured simulations were conducted towards the performance of asphalt pavements at mesoscales. A novel “locally homogenous” model together with the local homogenization approaches were proposed to simulate the linear and nonlinear behavior of asphalt pavements with different aggregate gradations. Several case studies have been presented to prove the capabilities of the proposed models and approaches. In future research, field or in-situ tests should be employed to exhibit the effectiveness of the locally homogenous models in pavement simulations.
- Record URL:
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Supplemental Notes:
- Dissertation
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Corporate Authors:
RWTH Aachen University, Institut für Straßenwesen
Mies-van-der-Rohe-Straße 1
Aachen, Germany 50274 -
Authors:
- Du, C
- Publication Date: 2022
Language
- German
- English
Media Info
- Media Type: Digital/other
- Features: Appendices; Figures; References; Tables;
- Pagination: XIV+196p
Subject/Index Terms
- ITRD Terms: 2944: Asphaltstraße (Oberbau); 5567: Belastung; 4967: Bituminöses Mischgut; 5455: Mechanik; 6205: Modell; 9103: Simulation; 9001: Verhalten; 4577: Zuschlagstoff
- Subject Areas: I22: ENTWURF VON VERKEHRSINFRASTRUKTUR;
Filing Info
- Accession Number: 01905487
- Record Type: Publication
- Source Agency: Forschungsgesellschaft für Straßen- und Verkehrswesen (FGSV)
- Files: ITRD
- Created Date: Jan 24 2024 1:55PM