Investigation of Toughening Mechanisms in the Fracture of Asphalt Concrete Using the Clustered Discrete Element Method

Asphalt concrete is a quasi-brittle composite material which is composed of solid inclusions and a viscous matrix. The fracture of heterogeneous solids is a difficult problem to handle numerically due to the creation and continuous motion of new surfaces. A clustered discrete element method (DEM) is employed as a means to investigate fracture mechanisms in asphalt concrete at low temperatures. A bilinear cohesive softening model is implemented into the DEM framework to enable simulation of crack initiation and propagation in asphalt concrete. The meso-scale representation of the morphology of the material is incorporated into the DEM model using high-resolution imaging and image analysis software. The bulk properties and fracture parameters of multi-phase are obtained from experiments and calibration procedure. The two-dimensional clustered DEM method is applied into mode I fracture tests, e.g. disk-shaped compact tension (DC(T)) and single-edge notched beam (SE(B)) tests, to investigate various fracture mechanisms of asphalt concrete. The simulation results are shown to compare favorably with experimental results, and moreover, the simulations provide new insight into the fracture mechanisms in asphalt concrete. The modeling technique provides a physical description of the fracture process zone in laboratory fracture tests, the influence of temperature, effects of material parameters, loading rate dependency, and specimen size effect on fracturing of asphalt concrete. The abilities to simulate mixed-mode fracture, crack competition, distribution of macro- and micro-cracks, and field fracture phenomenon are demonstrated in conjunction with SE(B) and multi-scale pavement fracture models.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Civil Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Kim, Hyunwook

Contributors dc:contributor

• Buttlar, William G.

• Engineering, Civil

Language dc:language

eng

Identifier

(MiAaPQ)AAI3290273

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83343