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Advanced Pavement Mechanics and Materials

Research Group Profile
Michigan Technological University
Advanced Pavement Mechanics and Materials
Core Competencies
  • Modeling pavement-wheel interactions
  • Aggregate-aggregate interactions
  • Modeling of cohesive and adhesive strength in asphalt mixes
  • Modeling & measurement of asphalt concrete in various loading conditions
  • Application of models in pavement scales and other materials such as warm mix asphalt, low emission asphalt, and recycled materials

 

rgp_YOU_feb2014
Example of DE models of a compacted asphalt concrete sample with various “element” sizes

Current Research Team Members:

  • Zhanping You (PI)
  • Xu Yang (Ph.D. candidate)
  • Mohd Rosli Mohd Hasan (Ph.D. Candidate)
  • Hui Yao (Ph.D. student)
  • David Porter (Ph.D. student) 
      

Recent PhD Graduates:

  • Baron Colbert (Ph.D. 2013), now Blue Harbor Energy
  • Shu Wei Goh (Ph.D. 2011), now Co-Founder and Chief Executive Officer of Universal Pave in Malaysia
  • Julian Mills-Beale (Ph.D. 2011), now Assistant Professor, California Baptist University
  • Yu Liu (Ph.D. 2010), now Associate Professor, Chang’an University, China
  • Sanjeev Adhkari (Ph.D. 2008), now Assistant Professor, Morehead State University

 

Problem
Asphalt mixture is a composite material of graded aggregates combined with asphalt binder and a certain amount of air voids. This multiphase material can be modeled with three phases: sand mastic, coarse aggregate, and air void phases. The mastic phase (sand mastic) includes fine aggregate, sand, and fines which are embedded in a matrix of asphalt binder. In the past decades, researchers have used various methods such as finite element models and discrete element models to study the complex behavior of asphalt mixtures. One example is the study of the modulus prediction of asphalt concrete with different sizes and shapes of aggregates bonded with time and temperature-dependent asphalt.
    
However, recent studies have shown that the 2D models do not adequately describe the complex microstructure of asphalt mixtures. These models predict over or under the modulus of asphalt mixtures due to the inability to incorporate the aggregate interlock’s contribution to the overall response of the mixture. The 3D models are expected to have a better capability to predict the mixture’s aggregate interlock and improve the predictions. Therefore, 3D microstructure based modeling techniques for asphalt mixture materials are needed to improve the understanding of the fundamental properties of asphalt mixtures and pavements.

Approach
The 3D models of the materials microstructure shall be developed to study the various viscoelastic or viscoplastic properties. In the developed models, the aggregate interlock, aggregate-aggregate interlock, adhesion and cohesion in the asphalt mixture shall be modeled. The fracture, large deformation, cracking due to load and low temperature events shall also be modeled for various purposes.  In addition, the models shall be validated with comprehensive experimental work.
Recent Findings
It was found that the 3D discrete element (DE) models were able to predict the mixture moduli across a range of temperatures and loading frequencies. The 3D model prediction was found to be better than that of the 2D model. The simulation speed of using discrete element models can be improved significantly by using some technologies such as a special designed frequency-temperature superposition algorithm in the models. The 3D DE model can also simulate the fracture behavior of asphalt mixture.
Impact
Microstructure-based modeling techniques are recognized as important research areas in engineering and materials science. We believe as the advances of computing technology and improvement computer power, the research work will significantly advance the understanding of asphalt materials, resulting in safer, more secure, and more durable asphalt pavement structures.
Selected Publications
Fundamental Study on Pavement-Wheel Interaction Forces through Discrete Element Simulation, by Y. Liu, Z. You, International Journal of Pavement Research & Technology 6 (6), 2013

Three-dimensional discrete element modeling of asphalt concrete: Size effects of elements, by Y. Liu, Z. You, Y. Zhao, Construction and Building Materials 37, 775-782, 2012

Accelerated discrete-element modeling of asphalt-based materials with the frequency-temperature superposition principle, by Y. Liu, Z. You, Journal of Engineering Mechanics 137 (5), 355-365, 2010

Three-dimensional microstructural-based discrete element viscoelastic modeling of creep compliance tests for asphalt mixtures, by Z. You, Y. Liu, Q. Dai, Journal of Materials in Civil Engineering 23 (1), 79-87, 2010

Three-dimensional discrete element simulation of asphalt concrete subjected to haversine loading: An application of the frequency-temperature superposition technique, by Z. You, Y. Liu, Road Materials and Pavement Design 11 (2), 273-290, 2009

Viscoelastic model for discrete element simulation of asphalt mixtures, by Y. Liu, Q. Dai, Z. You, Journal of engineering mechanics 135 (4), 324-333, 2009

Three-dimensional discrete element models for asphalt mixtures, by Z. You, S. Adhikari, Q. Dai, Journal of engineering mechanics 134 (12), 1053-1063, 2008

More can be found: You - Publications.