Parameter optimisation of a 2D finite element model to investigate the microstructural fracture behaviour of asphalt mixtures. (October 2019)

• Record Type: Journal Article
• Authors: Kollmann, Jonas; Lu, Guoyang; Liu, Pengfei; Xing, Qinyan; Wang, Dawei; Oeser, Markus; Leischner, Sabine
• Is Part Of: Theoretical and applied fracture mechanics. Volume 103(2019)
• Publication Date: 2019-10
• Subjects: Asphalt mixture -- Fracture behaviour -- Microstructure -- Finite element modelling -- Cohesive zone model; Fracture mechanics -- Periodicals; 620.1126
• DOI: 10.1016/j.tafmec.2019.102319
• Languages: English
• ISSNs: 0167-8442

Abstract

Highlights: FE models are constructed by digital image processing of X-ray CT scans. Visco-elasticity is considered for asphalt mortar in the micro-structural FE model. Cohesive elements are inserted in the FE models to facilitate multiple crack paths. The parameters governing the numerical solutions are optimised. Abstract: To mitigate the risk of asphalt degradation of pavement surfaces and to increase the durability, there is a need to investigate the fracture behaviour of asphalt mixtures at low and intermediate temperatures. The indirect tensile test (IDT) is widely used to characterise the fracture resistance in terms of tensile strengths of the asphalt mixtures. This paper presents an optimised method for two-dimensional (2D) finite element (FE) modelling of the IDT to simulate crack initiation and propagation within the asphalt mixtures on the microscale. X-ray computed tomography (X-ray CT) scanning and digital image processing (DIP) techniques were applied to detect and reconstruct the microstructure of asphalt specimens. Cohesive zone modeling (CZM) techniques were applied in the FE simulations to represent the fracture behaviour. The procedure of the FE modelling and parameter optimisation are described comprehensively. Four important parameters governing the numerical solutions during the simulation process were optimised based on counts of accuracy as well as computational efficiency. The optimised models were also validated based on experimental results. As a case study, the influence of the loading orientation on the fracture behaviour of asphalt mixtures was investigated. The validation and case study prove the reliability and applicability of the proposed FE modelling algorithm; further improvements will be carried out to facilitate the development of the pavement design process.